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£i UNEP WCMC World Atlas of

Edmund P. Green and Frederick T. Short 3 qR^

Seagrasses a group of about sixty

of underwater marine flowering , grow in

the shallow marine and environments of all the

world's except Antarctica. The primary food

of such as manatees, , and green

, and critical habitat for thousands of other ani-

mal and species, seagrasses are also considered

one of the most important shallow-marine ecosystems

for humans, since they play an important role in fishery

production. Though they are highly valuable ecologically

and economically, many habitats around the

world have been completely destroyed or are now in

rapid decline. The World Atlas of Seagrasses is the first

authoritative and comprehensive global synthesis of the

distribution and status of this critical marine habitat.

Illustrated throughout with color maps, photographs.

tables, and more, and written by an international team

of collaborators, this unique volume covers seagrass

ecology, scientific studies to date, status.

changing distributions, threatened areas, and conserva-

tion and management efforts for twenty-four of

the world. As human populations expand and continue

to live disproportionately in coastal areas, bringing new

threats to seagrass habitat, a comprehensive overview Digitized by tine Internet Arciiive

in 2010 with funding from UNEP-WCIVIC,

http://www.arcliive.org/details/worldatlasofseag03gree

World Atlas of Seagrasses Published in association with UNEP-WCMC by the University of California Press

University of California Press Berkeley and Los Angeles, California

University of California Press. Ltd. London, England

® 2003 UNEP World Conservation Monitoring Centre UNEP-WCMC 219 Huntingdon Road Cambridge CBS DDL, UK Tel: +^^101 1223 277 3U Fax:+4Z,(0| 1223 277 136 E-mail; infoHunep-wcmc.org Website: wvtfw.unep-wcmc.org

No part of this book may be reproduced by any means or transmitted into a machine language without the written permission of the publisher

The contents of ttiis volume do not necessarily reflect tfie views or policies of UNEP-WCMC. contributory organizations, editors or publishers. The designations employed and the presentations do not imply the expression of any opinion whatsoever on the part of UNEP-WCMC or contributory organizations, editors or publishers concerning the legal status of any country, territory, city or area or its authority, or concerning the delimitation of its frontiers or boundaries or the designation of its name or allegiances.

Cloth edition ISBN 0-520-24047-2

Cataloging-in-publication data is on file with the Library of Congress

Citation Green E.P and Short F.t 120031 World Atlas of Seagrasses. Prepared by the UIMEP World Conservation

Monitoring Centre. University of California Press, Berkeley, USA. iiPiSi UNEP WCMC

World Atlas of Seagrasses

Edmund P. Green & Frederick T. Short

UNIVERSITY OF CALIFORNIA PRESS Berkeley Los Angeles London WORLD ATLAS OF SEAGRASSES

World Atlas of Seagrasses

Prepared by UNEP World Conservation Monitoring Centre 219 Huntingdon Road UNEP WCMC

Cambridge CB3 DDL, UK The UNEP World Conservation Monitoring Centre is the

Tel: +U 10) 1223 277 3U assessment and policy implementation arm Fax: +4ilOI 1223 277 136 of the United Nations Environment Programme lUNEPl, E-mail: infoOunep-wcmcorg the world's foremost intergovernmental environmental

Website: www.unep-wcmc.org organization. UNEP-WCMC alms to help decision-

makers recognize the value of biodiversity to people

Director everywhere, and to apply this knowledge to all that they

Mark Collins do. The Centre's challenge is to transform complex data

into policy-relevant information, to build tools and

systems for analysis and Integration, and to support the needs of nations and the international community as they

engage In joint programs of action.

UNEP-WCMC provides objective, scientifically rigorous products and services that include ecosystem assess- Scientific editors ments, support for Implementation of environmental Edmund P. Green agreements, regional and global biodiversity In- Frederick T. Short formation, research on threats and impacts, and

Assistant scientific editor development of future scenarios for the living world. Michelle Taylor

Cartographer Corinna Ravilious

Technical editor Catherine Short

Layout Yves Messer Illustrations in Appendix 3 and at foot of pages:

A Banson production 27 Devonshire Road Mark Fonseca: marina Cambridge CBl 2BH, UK Phillips RC, Mehez EG [1988]. Seagrasses. Smithsonian Color separations Contributions to the Marine Sciences 3^. Smithsonian Swaingrove Institution Press, Washington DC: .

Printed in China QDPI Northern Fisheries Centre, Cairns: australis. Halophila capncorni. Jackson Estuarine Laboratory contribution number

396. Ron Phillips: All remaining illustrations. Supporting institutions

Supporting institutions

The United Nations Environment Programme is the principal United Nations body in the field of the

environment. Its role is to be the leading global environmental authority that sets the global environmental agenda, promotes the coherent implementation of the environmental dimension of sustainable development within the United Nations system and serves as an authoritative advocate for the global environment, http://www.unep.org

The UK Department for Environment, Food and Rural Affairs is working for sustainable development;

a better quality of life for everyone, now and for generations to come. This includes a better environ-

ment at home and internationally, and sustainable use of natural resources; economic prosperity defra through sustainable farming, fishing, food, water and other industries that meet consumers' requirements; thriving economies and communities in rural areas and a countryside for all to enjoy.

The Department for International Development is the UK Government department working to DFID promote sustainable development and eliminate world poverty This publication is an output from a research program funded by DFID for the benefit of developing countries. The views expressed are not

necessarily those of DFID. http;//v7ww.dfid.govuk/

international and national support The David and Lucile The David and Lucile Packard Foundation, started in 1964, provides Packard Foundation to non-profit organizations in conservation, science and many other areas. The foundation currently provides funding to SeagrassNet, a global seagrass monitoring program based at the University of New Hampshire. http;//www.packard. org/, http;//www.seagrassnet.org/

The University of New Hampshire is a land-grant, sea-grant and space-grant public institution with A'UNIVtRSirr of NiW HAMPSHlRf 10 000 undergraduate and 2 000 graduate students, and a well-established marine program. The Jackson Estuarine Laboratory is the primary marine research organization at UNH and has a strong seagrass research component, http://www.unh.edu/, http://marine.unh.edu/jel/home.html

World Seagrass Association is committed to the science, protection and management of the woridMsugmss Asmi/moN The seagrass ecosystem worldwide. The members come from many countries and include leading

scientists in marine and seagrass biology The association supports training and information exchange and raises global awareness of seagrass science and environmental management issues. http://www.worldseagra5s.org/

The Convention on Wetlands, signed In Ramsar, Iran, in 1971, is an intergovernmental treaty which provides the framework for local, regional and national actions for the conservation and wise use of wetlands and their resources. There are presently 135 Contracting Parties to the Convention, with

1 230 wetland sites, totaling 105.9 million hectares, designated for inclusion in the Ramsar List of Wetlands of International Importance, http://ramsar.org/

The International Action Network is an innovative and dynamic global partnership of many

of the world's leading science and conservation organizations. Established in 1999 to halt

iCRAN partnership on its partners' and reverse the decline of the health of the world's coral reefs the draws

investments in reef monitoring and management to create strategically linked actions at local, International Coral Reef A national and global scales, http://icran.org/

.^^-^ The Scientific Committee on Oceanic Research (SCORl was the first interdisciplinary body formed by the International Council for Science. SCOR activities focus on promoting international cooperation in Scientific Committee on Oceanic Research planning and conducting oceanographic research, http://www.jhu.edu/-scor

^ The Estuarine Research Federation lERFI is a private, non-profit organization. The federation was created in 1971 to address broad estuarine and coastal issues; it holds biannual international ^ meetings and supports the scientific publication , http://www.erf.org/ WORLD ATLAS OF SEAGRASSES

Acknowledgments

The World Atla5 of Seagrasses is a product of global collaboration between many different people but a few nnerit a special mention and deserve extra thanl

Corinna Ravilious, and technical editor, Catherine Short, have been equally Invaluable In the synthesis of information from many hundreds of disparate sources and for ensuring consistency throughout every section. The editors have a particular debt of gratitude to all these people.

Ttie origins of the World Atlas of Seagrasses go back to late 1997 when the need for a global compendium of information on seagrasses was first acknowledged. Hans de Jong, Eddie Hegerl, Paul Holthus, Richard Luxmore and the participants at the third International Seagrass Biology Workshop, 19-26 April 1998, Ivlanlla and Bolinao, Philippines, were particularly helpful In pulling these ideas together Nicholas Davidson, Salif Diop, Will RogowskI, Ed Urban, Genevieve Verbrugge and Marjo Vierros provided great support during the fundraising, support which was Instrumental in making the necessary resources available. We are, of course, notably grateful to our sponsors, listed at the beginning of the World Atlas, for Investing funds in this work. Special mention Is due here to the David and Luclle Packard Foundation and University of New Hampshire for supporting Fred Short's time. A long period of data collection followed soon after work began and involved much detailed correspondence with very many people. Our thanks go out to everyone who answered our phone calls and e-mails, but even more so to those who provided us with seagrass distribution data or maps, especially William Allison, Alex Arrivlllaga, Susanne Baden, Seth Barker, David Blackburn, Simon Blyth, Christoffer Bostrbm, NIkki Bramwell, f^arnie Campbell, Jacoby Carter, Rob Coles, Helen Cottrell, Lucy Conway, Charlie Costello, Jeffrey Dahlin, Dick de Jong, Karen Eckert, Caroline Erftemeljer, Randolph Ferguson, Mark FInkbelner, Terence Fong, Mark Fonseca, Sarah Gage, Martin GuUstrom, Rob

Hughes, Herman Hummel, HitoshI llzumi, Chung II Choi, Emma Jackson, Pauline Kamermans, Hilary Kennedy, Ryo MabuchI, Ian May, Pete McLain, Thomas Meyer, Mark Monaco, KenjI Morlta, Ivan Nagelkerken, Brian Pawlak, Karin Pettersson, Ron Phillips, Martin Plus, Chris Pickerell, Jean Pascal Quod, Thorsten Reusch, Ron Rozsa, Jan Steffen, Marieke van Katwijk, Mikael von Numers, Rob Williams, Lisa Wood, Masumi Yamamuro and members of the Wider Sea Conservation Network IWIDECAST): Timothy Austin, Andy Caballero, Didiher Chacon, Juan Manuel Diaz and Alan Mills. Clearly a number of data sharing agreements were necessary as these data were Identified and we thank Mary Cordiner for sorting out these institutional complexities.

The coordinators of the Global Seagrass Workshop, Mark Spalding and Michelle Taylor, and all 23 delegates (page 2831 are gratefully acknowledged for the time and effort they made to review, amend and correct the seagrass distribution data. The workshop itself would not however have been possible without considerable logistic and organizational support from Janet Barnes, Joy Bartholomew, Jean Finlayson, Anne Giblin, Pam Price, Ed Urban and Susan White, also all the staff at the Tradewlnds Hotel, St Petersburg , Florida. Jamie Adams, Mary Edwards and Sergio Martins have provided additional geographical information systems support at various stages during the preparation of the maps for the World Atlas and Elizabeth Allen, Janet Chow, Mary Cordiner and Michael Stone have spent very many long hours formatting and organizing the reference sections for the chapters and on-line bibliography (http://wAww.unep-wcmc.org/marine/seagrassatlas/referencesl.

Readers will quickly note the wonderful photographs which have been kindly donated. Credit is given next to Individual photographs but thanks are also due here to Nancy Diersing, Florence Jean, Karlne Magalhaes, Kate Moran and John Ogden all of whom helped us track down owners of pictures which we wanted to use. Most of the drawings of seagrasses In Appendix 3 and illustrated at the foot of the pages were donated by Ron Phillips, whom we especially thank for this contribution. Rob Coles, Mark Fonseca and Mike Fortes provided additional drawings for Appendix 3 and the page corners, and we thank them as well.

When reviewing correspondence and notes spanning the last five years It is all too easy to overlook or forget someone. Sincere apologies to anyone whom we have neglected to mention here. Please be assured that this was simply an oversight brought about by the effort of completing the book and nothing else!

Ed Green and Fred Short Preface

Preface

Conservation Monitoring is with great pleasure that I introduce this new book from the UNEP World ItCentre. The World Summit on Sustainable Development adopted, in the area of biodiversity, a

commitment to reverse the trend of losses by 2010. To achieve this we need hard facts on which to base decisions. The World Atlas of Seagrasses meets that need for a vital marine ecosystem whose importance has largely been overlooked until now.

This book would not have been possible without a remarkable collaboration between the 58 authors from 25 countries. The World Atlas of Seagrasses has played a role in fostering international collaboration by gathering information from many different sources all over the world. On behalf of UNEP I would like to express my gratitude to all the authors who have contributed their knowledge.

the World Atlas of Seagrasses including the UK Department for I would also like to thank the sponsors of Environment, Food and Rural Affairs, the UK Department for International Development, the Secretariat of the Ramsar Convention on Wetlands, the David and Lucile Packard Foundation, the University of New Hampshire, the World Seagrass Association, the Scientific Committee on Oceanic Research, the Estuarine Research Federation and the International Coral Reef Action Network.

will not only UNEP but all interested parties to focus on the I am confident that this book help implementation of sustainable development in the marine environment worldwide.

Klaus Toepfer Executive Director, United Nations Environment Programme lUNEP) WORLD ATLAS OF SEAGRASSES

Foreword

describing the complex relationships that exist in the living world we all too often focus on the

Inmaestros that take center stage. It is true that rain forests, coral reefs, whales, tigers and the like

carry an important representational role as they fill our television screens and become a priority in our conservation programs. But we should not forget the many other ecological that make up nature's orchestra. The living world is an interactive and integrated continuum that we partition into ecosystems for our own scientific convenience. The less well-known ecosystems often play a distinct and very important part in the overall harmony that we need to maintain, but only poorly understand. One such ecosystem is the beds of seagrass that are found on coastlines around the world.

Seagrass beds are unusual in that they are very widespread, occurring on shallow coastlines in all but the coldest waters of the world. A small group of flowering plants, just 60 among the 270 000 species of , plants and other organisms that have colonized the sea, they owe their success to this ability to tolerate a wide range of conditions. So why have they been selected for this global report ''

First of all, seagrass beds are an important but under-rated resource for coastal people. Physically they protect coastlines from the erosive impact of waves and , chemically they play a key role in nutrient cycles for fisheries and biologically they provide habitat for fish, and priority ecotourism icons like the , manatee and green turtle. And yet, despite these important attributes, they have been overlooked by conservationists and coastal development planners throughout their range.

This World Atlas of Seagrasses is literally putting seagrass beds onto the map, for the first time. It is a groundbreaking synthesis that provides people everywhere with the first world view of where seagrasses occur and what has been happening to them. It is a worrying story. Seagrass beds have been needlessly destroyed for short-term gain without real analysis of the values that the intact ecosystems bring to coastal society. There is no proper strategy for their protection. Their significance is not well appreciated and awareness is very low. This World Atlas W\[\. go a long way towards reversing these trends.

As ever in the production of an analysis of this kind, our scientists at the UNEP World Conservation

Monitoring Centre have been able to achieve their results only by standing on the shoulders of giants. We acknowledge and applaud the dedicated band of seagrass ecologists and taxonomists who have laid the

groundwork for this World Atlas and prepared much of the text. I hope it will bring well-deserved recognition for them and for their seagrasses, and establish a baseline from which to build a more sustainable future for coastal peoples and the home of the gentle dugong.

Mark Collins Director. UNEP-WCMC Contents

Contents

Acknowledgments vi 1.3 Norwegian eelgrass coverage 31

\M Map of eelgrass area distribution in Preface vii Danish coastal waters 32

Foreword viii 1.5 Maximum colonization depth of

eelgrass patches in Danish estuaries Introduction to the World Atlas of Seagrasses 1 and along open in 1900 and Key to maps and mapping mettiods 4 1996-97 33 1.6 Secchi depths and maximum Global overview colonization depths of eelgrass patches

The distribution and status of seagrasses in Danish estuaries and open coasts in Maps 1900 and 1992 33

1 World seagrass distribution 21 1.7 Long-term changes in the distribution

2 Global seagrass biodiversity 22 of eelgrass [Zostera manna] in the Figures southeastern (Puck ,

1 Relative size-frequency distribution of ] 33

538 seagrass polygons in latitudinal swathe 20-30°5 U 2 The SEAGRASSES OF Western 38 2 Growth of marine protected areas which Maps

include seagrass ecosystems, shown both 2.1 (north! 39

as the number of sites llinel and the total 2.2 Western Europe (south) 39 area protected (shaded area) 20 Case Studies Tables 2.1 TheWaddenSea 41

1 A list of seagrass species by family 2.2 Glenan 45

2 Major taxonomic groups found in seagrass ecosystems, with brief notes 3 The SEAGRASSES OF The western Mediterranean 48 3 Threatened species regularly recorded Map from seagrass communities worldwide 12 3.1 The western Mediterranean 49 k Estimates of seagrass coverage for Case Studies

selected areas described in this 3.1 Italy 50 \NoddAiias 14 3.2 France 51 5 Functions and values of seagrass from 3.3 Spain 54 the wider ecosystem perspective 15 Tables 6 Summary of the goods and services 3.1 Examples of general features of provided by seagrass ecosystems 16 Mediterranean seagrass meadows 49 7 Summary of marine protected areas that 3.2 Distribution of seagrasses throughout

contain seagrass ecosystems, from the the western Mediterranean (Italy, France UNEP-WCMC Protected Areas Database 19 and Spam] 52

REGIONAL CHAPTERS 4 The seagrasses of The Black, Azov, Caspian

1 The seagrasses of and the Baltic and Aral 59 Sea 27 Map

Map 4 1 The Black, Azov, Caspian and Aral Seas 61

1.1 Scandinavia 29 Figures 5 The SEAGRASSES OF The eastern Mediterranean

1.1 Average (±1 SEI above-ground biomass and the 65 values for eelgrass \Zostera manna] Maps along the Baltic Sea coastline 28 5.1 The eastern Mediterranean 67 1.2 Aerial photographs of two typical exposed 5.2 The Red Sea 67 eelgrass \] sites at the Case Study Hanko , southwest Finland 30 5.1 Israeli of the of Flat 21 9

WORLD ATLAS OF SEAGRASSES

6 The SEAGRASSES OF The Arabian Gulf and Arabian 9.2 Occurrence of seagrasses in coastal lU states of 104 Map 9.3 Associated biota of seagrass beds of 6.1 The Arabian Gulf and Arabian region 75 India 105 Case Studies 6.1 The Conservancy 76 10 The SEAGRASSES OF Western 109 6.2 Rapid assessment technique 77 Map

6.3 Marine turtles and dugongs in the 10.1 111 Arabian seagrass pastures 79 Case Study Table 10.1 , Western Australia: How 6.1 Seagrass species in the Arabian region 75 seagrass shaped an ecosystem 116 Tables 7 The SEAGRASSES OF and 82 10.1 Western Australian endemic seagrass Map species 110 7.1 Kenya and Tanzania 83 10.2 Summary of major human-induced

Case Studies declines of seagrass in Western 7.1 Gazi Bay, Kenya; Links between Australia 113 seagrasses and adjacent ecosystems 84

7.2 Seagrass beach cast at Mombasa 1 The SEAGRASSES OF Eastern Australia 1 1 Marine Park, Kenya: A nuisance or a Map vital link"? 88 11.1 Eastern Australia 121 Case Studies 8 The SEAGRASSES OF and 11.1 Mapping deepwater (15-60 m)

southeastern 93 seagrasses and epibenthos in the Maps lagoon 124 8.1 Mozambique and southeastern Africa 94 FIGURE: Probability of the occurrence

8.2 The Seychelles 94 of deepwater seagrasses in the Great 8.3 Mauritius 94 Barrier Reef Lagoon Case Study FIGURE: Frequency of the probability of 8.1 and Bay area, occurrence of seagrasses within each southern Mozambique 96 depth stratum Figure 11.2 Westernport Bay 126 8.1 Digging of meadov\/s FIGURE: Distribution of estuanne

at Vila dos Pescadores, near Maputo city 99 habitats in Westernport Bay, Australia

Tables 1 1.3 Expansion of Green Island seagrass 8.1 Area cover and location for the meadows 128

seagrass Zostera capensis in South FIGURE: Seagrass distribution at Green

Africa 94 Island in 1994, 1972, 1959 and 1936

8.2 Seagrass cover and area lost in

Mozambique 99 1 The seagrasses of New Zealand 1 34 Map The SEAGRASSES OF India 101 12.1 New Zealand 135 Maps Case Study 9.1 India 103 12.1 A seagrass specialist 140 9.2 Andaman and Nicobar 103 Figure

Case Study 12.1 An example of changes in the historical

9.1 Kadmat Island 106 distribution of seagrasses in New TABLE: Characterization of a seagrass Zealand 139 meadow at Kadmat Island, Tables 12.1 Area of seagrass m New Zealand TABLE: Benthic macrofauna in the estuaries where benthic habitats have seagrass bed at Kadmat Island, been mapped 135

Lakshadweep 1 2.2 List of locations where seagrasses have

Figure been recorded in New Zealand 136 9.1 Abundance of seagrass species at various depths in the 13 The SEAGRASSES OF Thailand 144 (southeast coast] 105 Map Tables 13.1 Thailand 145 9.1 Quantitative data for major seagrass Case Study

beds in Indian waters 102 13.1 The dugong - a flagship species 147 67 1 8

Contents

Table Case Studies 13.1 Occurrence of seagrass species in 17.1 Akkeshi. eastern Hokkaido 189 Thailand U6 17.2 coast in Iwate Prefecture, northeastern Honshu 190 U The seagrasses of Malaysia 152 Tables Maps 17.1 Seagrasses recorded in Japan 186 li.1 Peninsular Malaysia 153 17.2 Traditional uses of seagrasses in Japan 188

U.2 Sabah 153 1 7.3 Estimates of total areas of algal and Case Studies seagrass beds in Japan in 1978 and li.1 The seagrass macroalgae community 1991, and the percent area lost 188 of Teluk Kemang 155

U.2 The subtidal seagrass community 1 The seagrasses of The Republic of Korea 1 93 of Tanjung Adang Laut 156 Map U.3 Coastal lagoon seagrass community at 18.1 Republic of Korea 195 Pengkalan Nangka. Kelantan 158 Case Study Table 18.1 Recent research on seagrasses 196 H.I Estimate of known seagrass areas in Tables Peninsular Malaysia 157 18.1 Physical characteristics of seagrass beds on the west, south and east coasts

1 5 The seagrasses of The western Pacific islands 1 of the Republic of Korea 194 Maps 18.2 Seagrass species distributed on the 15.1 Western Pacific islands IwestI 163 coasts of the Republic of Korea 194 15.2 Western Pacific islands least] 163 18.3 Habitat characteristics of seagrass Case Studies species in the Republic of Korea 195 15.1 Kosrae 164 18.4 Morphological characteristics of MAPS: Lelu Harbour ca 1900 and 1975 seagrasses distributed in the Republic Okat Harbour and Reef 1978 and 1988 of Korea 195 15.2 SeagrassNet - a western Pacific pilot 18.5 The estimated areas of seagrasses study distributed on the coasts of the Republic of Korea 197

1 The seagrasses of Indonesia 1 7 Map 19 The seagrasses of The Pacific coast of North 16.1 Indonesia 173 America 199 Case Studies Map 16.1 Bay, West Java 176 19.1 The Pacific coast of 201 16.2 Kuta and Gerupuk Bays, Lombok 177 Case Studies 16.3 Kotania Bay 178 19.1 The link between seagrass and TABLE: Distribution of seagrass migrating black brant along the Pacific Tables Flyway 200 16.1 Average biomass of seagrasses at 19.2 The link between the seagrass Zostera various locations throughout manna [ts'ats'ayem] and the Indonesia 172 Kwakwaka'wakw Nation, Vancouver 16.2 Average density of seagrasses at Island, Canada 202 various locations throughout the 19.3 The link between seagrasses and Indonesian Archipelago 172 humans in Picnic , Shaw Island, 16.3 Average shoot density of seagrass Washington, United States 203

species in mixed and monospecific Table

seagrass meadows in the 173 19.1 Zostera manna and 16.4 Average growth rates of seagrass basal area cover in the Northeast Pacific 204 leaves using leaf-marking techniques 174 16.5 Indonesian seagrass-associated flora 20 The seagrasses of The western North Atlantic 207 and fauna: number of species 175 Map 16.6 Present coverage of seagrasses in 20.1 The western North Atlantic 209 Indonesia 178 Case Studies 20.1 Portsmouth Harbor, New Hampshire 208 The Philippines and Viet Nam 1 83 and Maine FIGURE: Eelgrass distribution by depth Harbor, Great Bay Estuary, 1 The seagrasses of Japan 1 85 in Portsmouth Map on the border of New Hampshire and 17.1 Japan 187 Maine, United States 9

WORLD ATLAS OF SEAGRASSES

20.2 Ninigret Pond, Rhode Island 211 Case Studies FIGURE: Eelgrass distribution in Ninigret 23.1 Florida's east coast 236 Pond. Rhode Island (United States] 23.2 Parque Natural Tayrona, Bahia de plotted by depth tor 1974 and 1992 Chengue, Colombia 239 FIGURE: Change in eelgrass area in 23.3 Puerto Morelos Reef National Park 240 Ninigret Pond, Rhode Island (United States] plotted against increasing number 2i The seagrasses of : Brazil,

of houses in the watershed Argentina and Chile 243 20.3 Maquoit Bay, Maine 213 Map Table 24.1 South America 245 20.1 The area of eelgrass, Zostera manna, Case Studies in the western North Atlantic 212 24.1 Itamaraca Island, northeast Brazil 244 24.2 Abrolhos Bank, Bahia State, northeast 21 The SEAGRASSES OF The mid-Atlantic coast of Brazil 247

the United States 216 24.3 mantima in the Patos Lagoon Map system 248 21.1 The mid-Atlantic coast of the United Figure States 217 24.1 Cumulative number of companion Case Studies species to the Brazilian seagrasses 21.1 Seagrasses in Chincoteague Bay: a reported since 1960 245 delicate balance between disease, nutrient loading and fishing gear impacts 220 APPENDICES

FIGURE: Recovery and recent decline of 1 Seagrass species, by country or seagrass [Zostera marina and Ruppia territory 251 maritima] distribution in Chincoteague Bay

FIGURE: Aerial photograph taken in 1998 of 2 Marine protected areas known to a portion of Chincoteague Bay, Virginia, include seagrass beds, by country or seagrass bed showing damage to the bed territory 256 from a modified oyster dredge Figures 3 Species range maps 262 21.1 Seagrass distribution (mainly Zostera

manna and Ruppia maritima] in The Global Seagrass Workshop 287 218 21.2 Changes in seagrass [Zostera manna INDEX 288 and wnghtii] distribution in the Lookout area (southern Core Regional maps

Sound, North Carolina] between 1985 Europe Plate I, facing p 38

and 1988 218 Africa, West and South Plate III, facing p 102 Australasia Plate V, facing p 118 22 The seagrasses of The 22-1 The Pacific Plate VII, facing p 166

Map Asia Plate IX, facing p 182 22.1 TheGulf of Mexico 225 North America Plate XI, facing p 214

Case Studies The Caribbean Plate XIII, facing p 230 22.1 Tampa Bay 226 South America Plate XIV, facing p 231 22.2 Laguna Madre 228

FIGURE: Seagrass cover in the Laguna Color plates

Madre of Texas The beauty of seagrasses Plate II, facing p 39 22.3 Laguna de Terminos 231 Impacts to seagrass ecosystems Plate IV, facing p 103

Seagrass ecosystems Plate VI, facing p 1 1 23 The seagrasses of The Caribbean 234 Seagrasses and people Plate VIII, facing p 167 Map The sex life of seagrasses Plate X, facing p 183 23.1 The Caribbean 235 Diversity of seagrass habitats Plate XII, facing p 215 Introduction

Introduction to THE WORLD ATLAS OF SEAGRASSES

Seagrasses are valuable and overlooked habitats, worldwide. Both nutrient and sediment loading affect providing important ecological and economic water clarity: seagrasses' relatively high light require-

components of coastal ecosystems worldwide. ments make them vulnerable to decreases in light

Although there are extensive seagrass beds on all the penetration of coastal waters. Direct harm to seagrass world's continents except Antarctica, seagrasses have beds occurs from boating, and other declined or been totally destroyed in many locations. As construction in the coastal zone, dredge-and-fill the world's human population expands and continues activities and destructive fisheries practices. Human- to live disproportionately in coastal areas, a comp- induced global may well impact rehensive overview of coastal resources and critical seagrass distribution as sea level rises and severe habitats is more important than ever The World Atias storms occur more frequently. The World Atlas of

of Seagrasses documents the current global distri- Seagrasses makes it clear that seagrasses receive little bution and status of seagrass habitat. protection despite the myriad threats to this habitat. Seagrasses are a functional group of about Most of our understanding of seagrass ecosystems

60 species of underwater marine flowering plants. is based on site-specific studies, usually in developed

Thousands more associated marine plant and nations. Very little is known about the importance of species utilize seagrass habitat. Seagrasses range seagrasses in maintaining regional or global from the strap-like blades of eelgrass [Zostera biodiversity, productivity and resources, partly because

caulescens] in the , at more than A m long, seagrasses are under-appreciated and their distribution to the tiny, 2-3 cm, rounded leaves of sea vine (e.g. is so poorly documented. As a result, seagrasses are

Halophila decipiens] in the deep tropical waters of rarely incorporated specifically into

Brazil. Vast underwater meadows of seagrass skirt the plans and are vulnerable to degradation. Seagrass coasts of Australia, Alaska, , India, ecosystems in the Caribbean, Indian , Southeast east Africa, the islands of the Caribbean and other Asia and Pacific are especially poorly researched, yet it is

places around the globe. They provide habitat for fish in these regions that the direct economic and cultural and shellfish and nursery areas to the larger ocean, dependence of coastal communities upon marine and performing important physical functions of filtering resources, including seagrasses, tends to be highest. coastal waters, dissipating wave energy and anchoring The purpose of the World Atlas of Seagrasses is to

sediments. Seagrasses often occur in proximity to, and present a global synthesis of the distribution and status are ecologically linked with, coral reefs, , of seagrasses. Such syntheses are available for other

salt , bivalve reefs and other . coastal ecosystems and have been instrumental in Seagrasses are the primary food of manatees, dugongs creating awareness, driving clearer conservation and

and green sea turtles, all threatened and charismatic management efforts and focusing priorities at the

species of great public interest. international level. For example, over the last ten years, Seagrasses are subject to many threats, both opinion on the status of coral reefs has changed from a anthropogenic and natural. Runoff of nutrients and predominant view that the majority of coral reefs were sediments from human activities on land has major unaffected by human activities, to the present view in

impacts in the coastal regions where seagrasses thrive; which the global decline of coral reefs, and the increas- these indirect human impacts, while difficult to ing threats to them, are widely acknowledged. A similar measure, are probably the greatest threat to seagrasses understanding of seagrass ecosystems is needed in WORLD ATLAS OF SEAGRASSES

seagrass distribution, and seagrass functions and threats at a global level. Later, additional chapter

authors were asked to contribute to represent regions of the world not yet well covered; also, chapter authors

invited co-authors to join their effort. The geographical coverage of the World Atlas reflects this process. The second section of the World Atlas of Seagrasses consists of 24 regional and national chapters. In each chapter, the authors have synthesized knowledge of seagrasses, the plants' biogeography, ecology and associated species, historical perspectives and threats to the ecosystem as well as management policies pertaining to seagrasses. Wherever possible,

the authors have estimated the area of seagrass in

their region and summarized its status. Case studies throughout the chapters highlight particularly interest- A patch reef in the Philippines surrounded by a luxuriant mixed ing seagrass habitats and areas where human or

bed of hemprichii and isoetMium. natural impacts to seagrasses are of concern.

order to achieve the visibility and recognition necessary to protect this valuable global resource. Public percep-

tion translates into political interest. Perceptions of seagrass ecosystems must achieve comparable status with those of coral reef and ecosystems,

through the creation of global maps, global estimates of loss, knowledge of human impacts to the ecosystem, regular monitoring of ecosystem status and a global plan

of action to reverse seagrass ecosystem decline. It is our

hope that the World Atlas of Seagrasses will contribute to the more widespread recognition, understanding, and protection of seagrass ecosystems worldwide.

ORGANIZATION OF THIS WORLD ATLAS

The World Atlas of Seagrasses is presented in two sections. The first section comprises a Global Overview

of the state of our knowledge of seagrasses. It presents

detailed ecosystem distribution and species diversity

maps and the most accurate possible estimate of global seagrass area. Appendices supply seagrass

species lists for almost 180 countries and territories, a

list of marine protected areas known to include seagrasses and a collection of species range maps. The

Global Overview was based on a compilation of Dugong feeding on Halophila ovatis, Vanuatu, western Pacific

seagrass literature and a workshop held in Florida with islands. seagrass scientists from around the world contributing their regional knowledge and expertise. The Global Of course, any comprehensive atlas builds on Seagrass Workshop, sponsored by UNEP-WCMC, with the work of many scientists beyond the chapter considerable assistance from the World Seagrass authors. Seagrass science owes much to den Hartog's Association, was held in St Petersburg, Florida in Seagrasses of ttie World and the many subsequent November 2001 specifically to begin assembling publications and books that are referenced throughout

information on global seagrass distribution for the the World Atlas. All of the references used to compile World Atlas Isee page 2871. Twenty-three delegates the World Seagrass Distribution Map (reproduced on from 1 5 countries participated, and all are represented page 21), as well as the individual chapter references, here as chapter authors. The workshop was a forum for appear in an online bibliography at http://www. discussion on the organization of an atlas, regional unep-wcmc.org/marine/seagrassatlas/references. Introduction

Additionally, the sources of information that contribute to the World Seagrass Distribution Map may be queried online through a GIS database at httpV/www.stort. 9 unep-wcmc.org/imaps/marine/seagrass. Inevitably, in a complex collaboration of this type, some sources of data are overlooked. Indeed, we have become aware of -.__ additional sources of information on the distribution of seagrasses since our printing deadline. Readers with .^^JjK^^^B

• information on seagrass distribution that they would

like to add to the database may contact us directly.

The seagrass distributions mapped in this World Atlas were derived from scientific journals, books, other publications and reports, reliable websites and personal I.V communications. Where these sources provided maps of Si iMi^^] actual seagrass beds, that mapped extent of seagrass

(polygon! was entered directly onto the World Seagrass laT' 'l-j

Distribution Map. More frequently, publications and reduces water clarity and stimulates growth of other sources simply mention the occurrence of epiphytic , as on this Zostera marina in southern Norway.

expected to occur, based on individual species reports collected for the World Seagrass Distribution Map. Using

an overlay of all the species range maps, a global map of seagrass species diversity was created (reproduced on

page 221. Additionally, regional maps show the same information as the World Seagrass Distribution Map, but

at a finer scale and with the locations of the case studies

in the region. Finally, each of the chapters has its own map, showing seagrass distribution and important

locations discussed in the chapter.

THREATS TO SEAGRASSES The synthesis represented by the World Atlas of Seagrasses confirms that seagrasses are one of the most widespread marine ecosystems, quite possibly

the most widespread shallow marine ecosystem, in the world. They cover an area that can only be crudely

estimated at present; the area we are able to document

in the World Atlas is certainly a gross underestimate.

The threats to seagrasses worldwide are similar and widespread. Seagrasses everywhere are vulnerable to eutrophication from nutrient over-enrichment of the environment and to turbid conditions caused by upland

Women harvesting shellfish. Pinna murkata, from an intertidal clearing and , both leading to reduced light

seagrass flat at low , Matibane, Mozambique. availability. Seagrasses are also subject to total destruction through coastal construction and other

seagrass at a particular location (e.g. a bay, beach, town direct human impacts. Direct use of seagrass plants by

or known latitude/longitudel. In these cases, the humans is limited, but seagrass beds support impor-

seagrass occurrence is shown on the distribution map as tant coastal fisheries worldwide, and because they

a dot, designating the mentioned location. The World occur in easily accessible, shallow, sheltered areas Seagrass Distribution Map at the beginning of the World these are often subsistence fisheries. Seagrasses are

Atlas gives the compilation of all the available an important coastal ecosystem in need of more study, information on seagrass distribution, as both actual beds awareness and protection. and as locations indicated by dots, of all seagrass

species combined. Species range maps (in Appendix 3) Ed Green depict the area where a certain seagrass species may be Fred Short WORLD ATLAS OF SEAGRASSES

Essential information n ' ^/' CKA^ - Ce^s-e

LEGEND TO MAPS Bathymetry

0-200 m Seagrass (location only, extent unknown] 200-2000 m ^^^1 Seagrass area >2000m

Species range maps [Appendix 31

IIIIIj

Hydrocharitaceae II

Posidoniaceae

MAPPING METHODS

The seagrass features mapped throughout this World Atlas were derived and not extrapolation from rather inexact statements (e.g. the Kimberley

from very many different sources. Selection criteria were used when Coast] does create some apparent discrepancies but in all cases these

reviewing thousands of records from hundreds of sources to determine are due lo this decision. As such the collected total of seagrass features

which features would be mapped. mapped in the World Atlas should be regarded as a minimal

The approach adopted was one that minimized subjectivity For representation of actual coverage.

example a statement such as "...in Gerupul< Bay. southern Lombok. Two further rules were applied to the making of the seagrass

Ha/odu/e unmervis densities ranged from..." Ipage 1731 would result in a maps. Firstly, in some cases only crude maps were available, often

point at that location. At the scale of a global atlas a point in Gerupuk Bay covering very large areas with swathes simply indicative of the presence

is sufficiently accurate. Statements such as "extensive terracing of these of seagrass (e.g. the global National Geographic 2000 Coral World map].

expanses of the [of the Kimberley Coast. Western They were cut to match shallow bathymetry data to avoid

Australia] often results in seagrass, particularly Enhalus acoroides. high misrepresenting the depths at which seagrasses are found. Secondly,

in the intertidal just below the mangroves" (page 110] have not been when no specific location was available beyond the name of a very small

recorded on the maps because no exact locations or extent of seagrass island a point was placed in the center of that island. Yap, , is

were available. At the scale of a global atlas an assumption that seagrass one example. Seagrass is recorded as occurring all around Yap with no

occurs along large sections of the Kimberley coast would have been too more precise locators so this is recorded as a point centered on the

inaccurate without independent reference. Some islands or coastal areas island. Yap is small enough so that, at the scale at which these maps are

have comprehensive coverage on the maps. These are derived from most useful, a visible point covers the island entirely

studies where an entire area has been mapped in great detail, often using

aerial photography or satellite remote sensing. Corsica is one example'" 1 Pasqualini V. Pergent-lvlartini C. Pergent G [1999]. Environmental

and the data were available for inclusion in the World Atlas maps. The impact identification along Ihe Corsican coast (Niediterranean seal

decision to construct the maps only on referenced sources (e.g. Corsica] using image processing. Aquatic Botany bi: 311-320.

ABBREVIATIONS USED

m meter mg milligram psu practical salinity units (almost

km kilometer g gram equal to parts per thousand]

ha hectare kg kilogram UV ultraviolet

cm/s centimeters per second kcat calorie °C degrees Centigrade

Bold type is used to indicate the corresponding author and contact details at the end of each chapter. The distribution and status of seagrasses

Global overview THE DISTRIBUTION AND STATUS OF SEAGRASSES M. Spalding M. Taylor

C. Ravilious

F. Short

E. Green

Seagrasses are a mixed group of flowering plants environments. They are not true grasses. Although they wfiicfi grow submerged in shallow marine and are all , they do not have a single

estuarine environments worldwide, in many evolutionary origin, but are a polyphyletic group, places they cover extensive areas, often referred to as defined by the particular they inhabit. seagrass beds or seagrass meadows. Although there Five particular adaptations to enable survival in this are relatively few species of seagrass, the complex niche have been identified'": physical structure and high productivity of these eco- an ability to grow whilst completely submerged, systems enable them to support a considerable bio- which presents problems, notably of lowered gas mass and diversity of associated species. Seagrasses and rates of ; themselves are a critically important food source for an adaptation to sur^^ive in high, and often varying, dugong, manatee, sea turtles and waterfowl. Many salinity: other species of fish and invertebrates, including sea an anchoring system to withstand water horses, shrimps and , utilize seagrass for part movements; of their life cycles, often for breeding or as juveniles. a submarine pollination mechanism;

Seagrasses are considered to be one of the most an ability to compete with other species in the important shallow marine ecosystems to humans, marine environment. playing a significant role in fisheries production as well as binding sediments and providing some protection The adaptations have led to a number of from coastal . morphological characteristics which are widespread The overview summarizes the distribution, impor- amongst seagrasses, notably: flattened leaves (with the tance and status of seagrasses worldwide. Firstly we exception of Syringodium and some spp.l; consider the definition of seagrasses, both as species elongated or strap-like leaves (with the exception of and as habitats, and look at their geographic distribution species in the Halophila]; and an extensive patterns. Much of this work is the presentation of system of roots and '". entirely new datasets that have been developed for this Considerable arguments remain over the atlas, including a detailed distribution database and digi- nomenclature and taxonomic relations of the sea- tal maps compiled from numerous sources, often gener- grasses. and it is likely that there will be considerable ously contributed. Next we consider the importance of changes to the accepted classification in coming seagrasses to humans. Finally we look at human years'^" and hence to the number of species con- impacts on these ecosystems, including both threats and sidered to be seagrasses. In the present work we have management measures for the protection of seagrass adopted a conservative approach, and consider 59 beds. Much of this chapter has benefited from the spec- species, based on species lists used in Hemminga and ialist input of seagrass experts worldwide, and especially Duarte'^' and in Short and Coles'^', with further advice those who are also contributors to this World Atlas. from the authors of this World Atlas. These species

are listed in Table 1. It is important to bear in mind, Definitions however, that "the actual number of seagrass species Seagrasses are flowering plants which grow fully is a matter of debate, depending in part on their submerged and rooted in estuarine and marine proximity to the marine environment and on the level WORLD ATLAS OF SEAGRASSES

of discrimination in physical and and Lepilaena are occasionally important members of genetics"'*'. seagrass ecosystems, but are often regarded as

Many species of the genus Ruppia are accepted seagrass associates or facultative members of the as seagrasses, commonly occurring in the marine seagrass community. We have included Ruppia spp.

environment and often intermingled with other when they occur in marine and estuarine environ-

seagrass species'*'. Species in the genera ments, but these species are less well covered in the

Overview Table 1

A list of seagrass species by family

Genus Species Author Genus Species Author

Hydrocharitaceae Posidoniaceae

Enhalus acoroides iL.f.l Royle angustilolia Cambndge & Kuo

Halophiia australis Doty & Stone Posidonia australis Hooker f.

Halophiia baillonii Ascherson Posidonia conacea' Cambridge & Kuo

Halophiia beccani Ascherson lincluding the conspecific Posidonia robertsoniae""] \

Halophiia capncorni Larkum Posidonia denhartogif Kuo & Cambridge

Halophiia decipiens Ostenfeld Posidonia l

Halophiia engelmanni Ascherson ILI Deliie

Halophiia hawaiiana' Doty & Stone Posidonia ostenfeldif den Hartog

Halophiia johnsonit Eiseman Posidonia sinuosa Cambridge & Kuo

Halophiia minor' IZollingerl den Hartog

Halophiia ovalis IR.Brownl Hooker f Zosteraceae

Halophiia ovata' Gaudichaud Zostera asiatica Miki

Halophiia spinutosa IR. Brownl Ascherson Miki

Halophiia stipulacea IForsskall Ascherson Zostera capensis Setchell

Halophiia tncostata Greenway Zostera capncorni Ascherson

Thalassia hempnchii lEhrenbergl Ascherson lincluding the conspecific Zostera mucronata. Zostera muellen and

Thalassia testudinum Banks ex Kdnig Zostera novazelandica"""]

Zostera caulescens Miki

Cymodoceaceae Zostera japonica Aschers. & Graebner

Amphibolis antarctica ILabill.l Sonder et Ascherson Zostera manna Linnaeus

Amphibolis gnffithii IBlackl den Hartog Zostera noltii Hornemann

Cymodocea angustata Ostenfeld Zostera tasmanica IMartens ex Aschers.l den Hartog

Cymodocea nodosa lUcnal Ascherson Iformerly Heterozostera]

Cymodocea rotundata Ehrenberg & Hempnch ex Makino

Ascherson Makino

Cymodocea serrulata IR. Brownl Ascherson Phyllospadix scoulen Hooker

Halodule beaudettei* Iden HartogI den Hartog Ruprecht ex Aschers.

Halodule bermudensis' den Hartog S. Watson

Halodule emarginata' den Hartog

Halodule pinifolia* IMikil den Hartog Ruppiaceae

Halodule uninervis IForsskall Ascherson Ruppia cirrhosa IPetagnal Grande

Halodule whghtii Ascherson Iformerly spiralis]

Synngodium fililorme Kutzing Ruppia mantima Linnaeus

Synngodium isoetifolium lAschersonl Dandy Ruppia megacarpa Mason

Thalassodendron ciliatum IForsskall den Ruppia taberosa Davis & Tomlmson

Hartog

Thalassodendron pachyrhizum den Hartog Note:

* Species designations thai are i matter of debate and currently

under genetic and morphometnc investigation. |

t Species proposed as conspeci c with Halophiia ovali^"'-

\ 11 The distribution and status of seagrasses

Literature than many other species and have not been universatty accepted as seagrasses.

Typically, seagrasses grow in areas dominated by soft substrates such as or mud, but some species can be found growing on more rocky substrates (e.g.

Phyllospadix]. Seagrasses require high levels of light, more than other marine plants, because of their complex below-ground structures which include considerable amounts of non-photosynthetic tissues.

Thus, although they have been recorded to 70 m in clear waters'", they are more generally restricted to shallow waters due to the rapid attenuation of light with depth. Seagrasses can form extensive monospecific stands or areas of mixed species. Such areas are known as seagrass beds or meadows, and make up a unique marine ecosystem or biotope. Seagrasses can also grow in isolated patches, or as part of a habitat mosaic with other habitats such as , mangroves, bivalve reefs, rocky benthos or bare sediments.

Generally it is the larger seagrass beds and meadows which have been the subject of intensive study and mapping worldwide. Although typically permanent over Quadrat sampling in an intertidal Zostera wanna bed, Maine. USA periods of decades, seagrass systems can be highly dynamic, moving into new areas and disappearing from sources had been used in developing seagrass others over relatively short timeframes. distribution data Isee the online bibliography at http://www.unep-wcmc.org/marine/seagrassatlas/ DEVELOPING SEAGRASS DISTRIBUTION references]. These sources provide information on INFORMATION AND MAPS seagrasses in more than 120 countries and territories in order to develop a clearer picture of the distribution of worldwide, and the majority include information on seagrasses worldwide, a new dataset was developed at specific species. All data sources were documented UNEP-WCMC, based on literature review and outreach and can be queried online through the GIS Igo to to expert knowledge. An output from this dataset is http://stort.unep-wcmc.org/imaps/marine/seagrass]. presented here in the World Seagrass Distribution Map Despite the broad range of sources, the iMap 1. which appears on page 211. geographic information can be seen largely to fall into

Initial efforts focused on the acquisition of point- three categories, as discussed below. source information which was compiled into a spreadsheet with details on species as well as Direct habitat maps information on location in both descriptive terms and, Direct habitat maps are high-resolution maps, typically wherever possible, geographic coordinates. This work prepared from remotely sensed data but in some cases continued throughout a second data-gathering phase, mapped entirely from field observations; they during which maps on 'he distribution of seagrasses represent the polygons showing the true spatial extent were developed on a geographical information system of seagrass distribution. They provide the most

IGISI. The two datasets remained closely linked: the accurate data available for habitat distribution, but are point locations from the first phase were linked to the available for only a very limited area worldwide. In GIS, and the GIS layer also allowed for the some cases they do not provide species-specific incorporation of boundary information delimiting distribution information. Sources included some particular seagrass areas [polygons]. A third phase broader maps showing seagrasses over several involved the presentation of the initial maps prepared kilometers or tens of kilometers of coastline, but also by UNEP-WCMC to the Global Seagrass Workshop in many maps prepared and presented for individual study Florida, 2001, where they were thoroughly checked by sites in expert publications. regional and national seagrass experts. As a result, new data points were added, new datasets and Expert interpolations references were provided, and incorrectly located or In some cases, maps have been based on the spurious data points were removed. interpolation of ground-based knowledge and

At the conclusion of this effort, over 520 major observation - seagrasses may be known from a series

W! WORLD ATLAS OF SEAGRASSES

of point locations, and with an accurate benthic chart it associated with time. Seagrass systems are highly is possible to interpolate between these points to variable through time, with some showing seasonal generate an outline of assumed seagrass area. Clearly variations and others showing dramatic interannual the accuracy of such maps is highly variable, but can be variation. Finally, it is important on a composite map, relatively reliable with sufficient background infor- such as that presented here, to be aware that gaps mation and cautious interpretation. These maps were where there are no data cannot be distinguished from utilized with caution and included in the GIS only if gaps where seagrasses do not occur better data were unavailable and the source was The results of this data gathering have been used considered to be reliable. to show the distribution of individual species, and to

show the overall distribution of seagrass habitat. The

Point-based samples World Seagrass Distribution Map includes all the For wide areas of the globe, maps of any sort were species-specific information as well as additional unavailable; however, it was possible to gather accurate points and areas where species were not specified. point locations of seagrass beds from a large number of Interpolation of the species distributions was site-based seagrass publications, herbarium records used to generate species range maps Isee Appendix 31. and national species inventories. Clearly, as points, The known occurrences of each species were used to these give no indication of actual seagrass area, but they set the limits to a generalized outline of the range of are very useful in a broader mapping context where no that species. Like the raw datasets, preliminary range further information is available. maps were reviewed at the Global Seagrass Workshop

in Florida. It should be noted that they do not indicate

Developing the distribution map definite occurrence of a seagrass species, but rather

The source maps used for producing the World show where a species might be expected to occur Seagrass Distribution Map were created using many should environmental conditions be suitable. Such mapping techniques, and with various goals. There are maps are useful in biogeographic studies and also differences in resolution, which will clearly influ- comparisons between species, and also for predicting ence the area of seagrass portrayed on a map. With possible species occurrence in areas which have not remote sensing, accuracy is limited by the resolution been previously investigated. and bandwidths utilized by the sensor, the degree of The data that constitute the World Seagrass ground-truthing and sensitivity of the interpretation, as Distribution Map were also used to make a preliminary well as by the depth of the water column, the clarity of calculation of seagrass area at global and regional the water and other attributes of the benthos. Some levels. Such work has been done in more detail for remotely sensed images will pick up only shallow other nearshore marine habitats'"*'; however the l<10 m) seagrass beds with a high shoot density, while weaknesses and gaps in the seagrass dataset mean large pixel size will fail to capture small or highly that initial area calculations, presented below, are only patchy seagrass areas. Error also plays a part, and broadly indicative. some mapping systems may incorporate non-seagrass species, notably macroalgae. Although typically more SPECIES DISTRIBUTION accurate, direct sampling can have many similar From the world seagrass distribution datasets problems, particularly associated with water depth described above, we assembled species records for and clarity. more than 120 countries and territories. The datasets Combining data from multiple sources, as include some records for countries where point undertaken here, exacerbates these problems, as locations were unavailable (i.e. only species lists were there are always differences in both quality and available], and hence these are not shown on the maps. definition between studies. Seagrass shoot density All the datasets were used to generate species lists by varies considerably and, while some studies will country, presented in Appendix 1 . The species lists show consider only seagrass ecosystems where seagrass that the countries with greatest seagrass diversity are shoots are continuous at high densities [such a countries which extend into both tropical and temperate definition may in fact be forced by the mapping climates, including Australia 129 species!, the United techniques), others may include all areas of even very States (23 species including all overseas territories! and sparse seagrass growth. Differences in scale between Japan (16 species). The greatest seagrass species studies introduce further variance: lower resolution diversity in single-climate countries occurs in the maps may tend to ignore minor breaks in seagrass tropics. Tropical countries with the highest seagrass beds, while finer resolution maps will pick up even species diversity include India and the Philippines (both small breaks which, it could be argued, are still a part with H species) and Papua New Guinea (12 species). of the seagrass habitat. Further problems may be The Philippines and Papua New Guinea, together with The distribution and status of seagrasses

Indonesia 112 species], are considered to be the center of global seagrass biodiversity. The geographic data from the same seagrass distribution datasets were used to generate the species range maps presented in Appendix 3. (Range maps were not prepared for Ruppia species as the existing data were deemed insufficient.) The species range maps update earlier work by den Hartog'" and by Phillips and Mehez'". They show areas where the species may be expected to occur, but they may leave out some areas where seagrass information is not available. By amalgamating the species range maps, a

global map of seagrass biodiversity was created (Map 2, page 221. The biodiversity map indicates the number of

seagrass species in various parts of the globe; a

previous effort is provided in Hemminga and Duarte''".

Ivlap 2 IS modeled on similar maps compiled for corals""' and for mangroves"".

Biogeograpfiic patterns Halophila capncorni female flower. Lizard Island, Queensland. Map 2 shows the three clear centers of high diversity, Australia.

all of which occur in the . The first and largest of these lies over insular . unique to the North Pacific, occurring in both the The other two centers are adjacent to this region but east and the west.

remain distinctive, being Japan/Republic of Korea 4 Northeastern Pacific (l|: A lower-diversity temp- and southwestern Australia. Other areas of erate area, dominated by Zostera and Phyllospadix

significant diversity include southern India and species. This region is closely linked to the more

eastern Africa. Looking at diversity patterns in more diverse western North Pacific but also includes

detail, and also at the individual species ranges that three endemic species, ,

underpin them, it is possible to distinguish general Phyllospadix serrulatus and Phyllospadix torreyi.

regions of seagrass occurrence, each with distinctive 5 North Atlantic (llll. A low-diversity temperate

floral characteristics"'^'. The following list of area, dominated by Zostera and Ruppia species,

seagrass regions is largely based on Short et al™. with Halodule reaching its northern limit at 35°N

1 Tropical Indo-Pacific IIX in Short ef at™]. in North Carolina, USA. Europe is distinguished by

Mirroring the biodiversity found in coral reefs and having a second species of the Zostera genera,

mangrove forests, this is a region dominated by Zostera noltii. Zostera manna is the main species tropical seagrass species, with a great focus of of the region.

diversity in insular Southeast Asia and northern 6 Wider Caribbean (IVl. A tropical area with Australia, continued high diversity across the moderate seagrass diversity, including species of and up the Red Sea, but relatively Halodule, Halophila, Syringodium and Thalassia. rapid attenuation of biodiversity across the Pacific Although the tropical communities of Brazil are islands. Key genera include Cymodocea, Enhalus. geographically isolated they are not sufficiently Halodule, Halophila, Syringodium, Thalassia and distinct to merit consideration as a separate flora Thalassodendron. (limited to species of Halodule, Halophila and

2 Southern Australia IXI. A highly diverse region, Ruppia]. dominated by temperate species. The particular 7 Mediterranean (Vl|. An area of relatively diverse

center of diversity occurs in southwestern temperate and tropical seagrass flora, which

Australia (with species in the genera of includes seagrass communities just outside the Amphibolis, Halophila, Posidonia and Zostera]. Mediterranean in northwest Africa as well as

3 Northwestern Pacific ID. The third-highest communities in the Basin and the diversity region which, although connected to Caspian and Aral Seas. Species of Cymodocea,

insular Southeast Asia, is dominated by Posidonia and Zostera are common; Ruppia also temperate species (notably species of Zostera plays an important role in the region, particularly

and Phyllospadix]. The genus Phyllospadix is in the Black, Caspian and Aral Seas.

// WORLD ATLAS OF SEAGRASSES

8 IVIIII. The region has both temperate of seagrasses. The relatively low number of seagrass and tropical species from the genera Halodule, species could lead to the inference of a recent Hatophita. Ruppia, Synngodium, Thalassodendron evolutionary history; however den Hartog'" reports and Zostera. evidence for the existence of marine angiosperms as long ago as 100 million years, and there are clear

In addition to these floristically distinct regions examples of seagrass from the .

there are three other geographically distinct seagrass Further studies have failed to produce evidence of any areas which are of biogeographic interest, but which massive diversification or of major extinction events,

are poorly known and lack a distinctive floral and so it may be that seagrasses have simply followed characteristic, being largely depauperate. a relatively conservative evolutionary pathway. More

9 Chile llil. One species, Zostera tasmanica work IS required in this field'"'"'. (formerly Heterozostera], has been found along this coast. ASSOCIATED SPECIES AND HABITATS

10 Southwest Atlantic IVl. Along the coast of Seagrasses do not grow in isolation but form an Argentina and southern Chile there are extensive integral and often defining part of highly complex communities of Ruppia. ecosystems. The seagrasses themselves are an

11 West Africa (Vll|. Only one species, Halodule important standing stock of organic matter, which is

wrightii, has been recorded; the distribution is relatively stable in the tropics and has broad intra-

poorly known. annual variation in temperate regions. The productivity

of these ecosystems is usually enhanced by other

Considerable further work is required in order to primary producers, including macroalgae and epiphytic understand fully the distribution patterns of sea- algae. The abundant plant material of seagrass beds grasses; to determine the patterns of evolution and forms an integral part of many food chains. migration of species; and to uncover the inter- Additionally, the complex three-dimensional structure

connections between these regions. Some of the of the seagrass bed is important, providing shelter and

patterns observed in the tropical floras mirror the cover, binding sediments and, at fine scales, even

patterns observed in corals and mangroves. The South- altering the patterns and strength of currents in the

east Asian center of diversity is a particular feature of water The complex, modified seagrass environment

several marine biodiversity maps produced to date, provides a great variety of niche spaces on and within including mangroves"" and several major groups of the sediments, on the plant surfaces and within the

coral reef taxa"". It is important to distinguish this water column.

Southeast Asian region from the separate centers of Thus, despite the relatively small number of

diversity seen in southwestern Australia and Japan, as seagrass species, a vast array of other species can be these two areas have larger ranges of climate from found within seagrass ecosystems. Many are obligate

temperate to tropical IMap 21. members of the seagrass ecosystem, found nowhere

Theories for the development of the Southeast else. Others may be restricted to seagrass areas for

Asian center of diversity have been advanced for a shorter periods of their life histories, using them as

number of species groups. It has been variously breeding or nursery areas, or settling there for their

suggested that this region may have been a center for adult lives. Many more are found across a broad range species accumulation linked to favorable ocean of marine habitats, but regularly inhabit seagrass

currents ("the vortex model of coral reef bio- areas. Table 2 provides a list of some of the major """!; a location where high diversity was taxonomic groups typically associated with seagrass maintained thanks to benign climatic conditions during ecosytems. recent ice ages"^'; or a center for species evolution with Seagrass ecosystems often play an important

the combination of benign conditions and changing sea role in the functioning of a wider suite of coastal and levels ("eustatic diversity pump model"""]. marine ecosystems, including coral reefs and man-

The high diversity of temperate species in Japan groves in the tropics, but also soft muddy bottoms,

and southwestern Australia is also of considerable intertidal flats, salt marshes, oyster reefs and even evolutionary interest, but its cause remains a matter of pelagic ecosystems.

speculation. There is evidence that the southwestern Levels of species diversity in seagrass eco- Australian flora may contain important relict systems can be very high indeed. Humm"" listed 113 elements"" but more recent events associated with the species of algal epiphytes from

dramatic changes during and following the last ice age beds in Florida. Using this, combined with lists from must also be considered. 26 other publications worldwide, Harlin'"' produced a

It is important to consider the evolutionary origin list of some 450 algal species that are epiphytic

\l The distribution and status of seagrasses

Overview Table 2

Major taxonomic groups found in seagrass ecosystems, with brief notes

Taxonomic group Notes

Bacteria

Fungi Including Plasmodiophora

Diatoms IBacillarlophytal

Blue-green algae ICyanophytal

Red algae IRtiodophytal Including calcareous species

Brown algae IPhyaeophytal Including Padina

Green algae (Chlorophytal Notably Ulva, Halimeda and Caulerpa

Protozoa Includes the slime molds Labyhnthula spp., and Foraminifera

Sponges Includes epiphytic and free-standing species

Cnidarians Includes epiphytic hydrozoans. sea anemones, solitary corals and Scleractmia such as Pavona,

Psammacora, Pontes, PociUopora, Siderastrea

Polychaetes Including rag-worms Inereidsl

Ribbon worms

Sipunculid worms

Flatworms

Crustaceans Includes amphipods, and many decapod including crabs, stomatopods and commercially

important shrimp and

Bivalve mollusks Some oysters and scallops, also many boring species

Gastropod mollusks A broad range including . Cypraea and commercially important species of Strombus

Cephalopod mollusks Sguid and cuttlefish often found over seagrass areas

Bryozoans Epiphytic on seagrass and rocks

Echinoderms A range of commercially important holothurian species, ophiroids are widespread, but also asteroids and

echmoids

Tunicates Ascideans

Fisti All groups, but including the commercially important Haemulidae igruntsl, Siganidae Irabbitfish],

Lethrinidae lemperorsl. Lutjanidae Isnappersl, Bothidae Heft-eye lloundersl, Syngnathidae (pipefishes and

sea horses!; many of the latter, which are used in the aquarium trade and Chinese medicine trade, are

considered threatened

Reptiles Notably the green turtle Chelonia mydas

Birds Notably brant Igeesel and other migrating waterfowl and wading birds

Mammals Notably the sirenian species dugong Dugong dugon and manatee Tnchechus manatus, Trichechus

senegaleosis

World Source: Key references for this table include various chapters in Phillips and McRoy"™, and review comments by the contributors to this

Atlas.

on seagrasses, still probably an uncierestimate. Despite this high diversity and the importance of Hutchings"" listed some 2A8 artfiropods, 197 mollusks, associated species, there is no detailed database of 171 polychaetes and 15 species from species associated with seagrass beds. Many of the in other Jervis Bay in New South Wales, Australia. In Florida, species that have been recorded are also found to restricted to Roblee et at."^' noted ICO species of fish and 30 species ecosystems, although some appear be for at least of crustaceans in seagrass beds. seagrass ecosystems or dependent on them A number of studies have compared diversity in a part of their life cycles. Such seagrass-dependent seagrass beds with that observed in adjacent eco- species range from particular epiphytic algae'™ to the systems. Seagrasses consistently have higher levels of large seagrass-grazing manatee and dugong. Most of diversity than adjacent non-vegetated surfaces; how- the comprehensive faunal assessments have been in temperate waters, or the relatively low- ever, if other vegetated surfaces, or coral reefs, are undertaken compared these often have similar to significantly diversity waters of the Caribbean, and it seems likely

in Indo-Pacific in particular will higher levels of diversity'^'. that further work the \\\\ WORLD ATLAS OF SEAGRASSES

lead to large increases in the recorded numbers of conservation actions. Using the species range maps, it seagrass associates. is possible to calculate the total area of each species

range. For such calculations it was necessary to modify

Threatened and restricted range species the broad range maps and not to include areas outside

Within the wider conservation arena, species with the in the calculations. These range- restricted distributions, together with threatened area statistics are provided next to the species range species, are often singled out for attention. Apart from maps in Appendix 3. From this work we can see that only concerns over these individual species, they are often a small number of species have truly restricted ranges, used as "flagship species" to draw attention to partic- notably: Halodule bermudensis |1 000 km'l, Halophila ular areas and issues. Amongst the seagrasses, hawaiiana 17000 km'l, Halophila johnsonii U2000 km'l, however, the problems of taxonomic uncertainty under- Posidonia ostenfeldii [66000 km'l, Posidonia kirkmanii mine the determination of both threat and restricted 166 000 km-] and Halodule beaudettei 17^000 km'l. range. However, all these six species are in the process Two species of seagrass have been listed as of taxonomic review and their individual species threatened by lUCN-The World Conservation Union'''' designations are presently in question.

(see Table 31: Halophila johnsonii and Phytlospadix Given the problems of taxonomy, and the low serrulatus. A number of countries harbor the sole threat to the existence of individual seagrass species, populations of a seagrass species (national endemics], measures of restricted range, endemism or threat of most notable of which is Australia, with 13 species extinction are probably of little value in seagrass found nowhere else in the world. Such national conservation efforts. Similar arguments are not true for endemism has no inherent ecological significance, seagrass-associated animals, although here lack of although it can be used as a basis to support knowledge hampers a true assessment of the full

Overview Table 3

Threatened species regularly recorded from seagrass communities worldwide

Species Common name Status Species Common name Status

Halophila johnsom Johnson's seagrass Vu Hippocampus kuda Spotted or horse Vu

Phyllospadix serrulatus Surf grass R Hippocampus reidi Slender sea horse Vu

Carcinoscorpius rotundicauda Horseshoe crab DD Hippocampus wtiitei V^hite's sea horse Vu

Tachypleus tndentatus Horseshoe crab DO Hippocampus zosterae Dwarf sea horse Vu

Hippocampus abdominalis Big-bellied sea horse Vu Epinephelus stnatus' Nassau grouper En

Hippocampus borboniensis Sea horse Vu Mycteroperca cidi* Venezuelan grouper Vu

Hippocampus breviceps Short-headed sea horse DD Mycteroperca microlepis' Gag grouper Vu

Hippocampus erectus Lined sea horse Vu Chelonia mydas Green turtle En

Hippocampus fuscus Sea pony Vu Dugong dugon Dugong Vu

Hippocampus histrix Spiny or thorny sea horse Vu Trichechus manatus West Indian manatee Vu

Hippocampus jayakan Sea horse Vu Trichechus senegalensis West African manatee Vu

Notes:

' Juveniles regularly observed in seagrass beds.

This list includes only species which are partially or wholly dependent on seagrasses and may be incomplete.

- DD Data Deficient: A is Data Deficient when there is inadequate information to make a direct, or indirect, assessment of its risk of

extinction based on its distribution and/or population status. A taxon in this category may be well studied, and its biology well known, but

appropriate data on abundance and/or distnbution is lacking.

R - Rare: Taxa with small world populations thai are not at present Endangered or Vulnerable but are at nsk. These taxa are usually localized

within restncted geographic areas or habitats or are thinly scattered over a more extensive range

- Vu Vulnerable: A taxon is Vulnerable when it is not Cnlically Endangered or Endangered but is facing a high nsk of extinction in the wild in the

medium-term future.

- En Endangered: A taxon is Endangered when it is not Cnlically Endangered but facing a very high nsk of extinction in the wild in the near future.

Cnlically Endangered: A taxon is Cnlically Endangered when it is facing an extremely high nsk of extinction in the wild in the immediate future.

Source: Walter and Gillett'^^'; lUCN'"', The distribution and status of seagrasses 13

threats facing many species. Table 3 provides a list of some of the known seagrass species and seagrass associates listed as threatened by lUCN'""'. The clear focus of this list towards a few groups is probably indicative of the general lack of knowledge of the status of many seagrass associates. This problem has also been more widely recognized by lUCN'"' which acknowledges that "there has been no systematic assessment" apart from some limited groups. Of the species which have been listed, most remain poorly known or are ranked at a relatively low level of threat such as "Vulnerable".

DISTRIBUTION OF SEAGRASS HABITAT The known locations of seagrass ecosystems, based on the mapping efforts described above, are presented in the World Seagrass Distribution Map IMap II and in the maps which appear in Chapters 1-24. In some parts of the world, notably the western North Atlantic, the Gulf of Mexico, Queensland lAustralial, Western Australia and some parts of the Mediterranean, the maps are based on fairly comprehensive information on seagrass distribution. Elsewhere, available A sea horse. Hippocampus kuda. among Enhalus acoroides, information is more sporadic, restricted to individual souttiern Peninsular Malaysia sites, bays or national coverages for smaller countries, though there may be some documentation of broader of South America and of much of West Africa may distribution patterns. Typically this is the case for indeed have more seagrass communities than are areas such as the western Pacific, the Indian Ocean reflected here. and the Caribbean. Over a few large stretches of the worlds coasts, there exists almost no information on CALCULATING GLOBAL SEAGRASS AREA whether or not seagrasses occur, let alone their The calculation of a global seagrass habitat area is very density, extent or species composition. This is notably important and useful for an assessment of the role of the case for West Africa, South America. Greenland, seagrasses in global processes, particularly in global northern China and the Siberian coast, and parts of carbon budgets, and also in assessing historical and Southeast Asia and the Pacific islands. future loss of seagrass and in priority setting and The World Seagrass Distribution Map shows the management of natural resources for activities such as broad distribution of seagrasses in most of the worlds fisheries and conservation. and seas, including the Black, Caspian and Aral To date the only global area estimate for Seas, and further shows the considerable latitudinal seagrasses has been one of some 600000 km"^^"' range of seagrasses. The most northerly locations for reportedly derived from Charpy-Roubaud and seagrasses are for Zostera marina which is recorded at Sournia'"'. The latter paper, however, does not provide

Veranger in Norway at 70°30'N, Cheshskaya Guba an area estimate directly, and it would appear that the in (67°30'Nl and in Alaska (at 66°33'N1. The figure of 600000 km^ is derived from a global estimate most southerly locations are for in of seagrass productivity'""' and typical seagrass New Zealand, with the southernmost record being at productivity figures taken from an unspecified source. i6°55'S on Stewart Island, and Ruppia maritima in the This estimate'"'*' seems too large, as the original source

Straits of Magellan |54°S1. of global productivity was itself based on an area

A limitation of these distribution maps is that estimate of only 350000 km^ for seagrasses, salt they provide no information on the extent of coast- marshes and mangrove communities combined. lines surveyed without finding seagrass and hence do The calculation of global and regional habitat not distinguish between "no seagrass" and "no areas tor the marine environment can be done using information". Gaps in the distribution maps may two broad approaches. The first is to estimate or model result from the lack of available data for certain parts probable habitat area utilizing known and mapped features or of the world, but in other areas they reflect knowledge parameters, such as bathymetry, coastal that no seagrass exists. Thus the western coastlines existing biogeographic knowledge. The second involves

;-/ 14 WORLD ATLAS OF SEAGRASSES

250 50 Overview Table i Average area Estimates of seagrass % coverage for selected areas ; described in this World Atlas 200 35.7 _40 4.84

Chapter Location Area Ikm 150 _30 1 Scandinavia 1850 2 Western Europe 338 1 1 100 3 Western Mediterranean 4152 353 JO i Euro-Asian Seas 2600 1 1 6 370 50 1 10 8 Mozambique 439 1 1 2 663 0.61 1 165 360 9 I I India 39 0^ 65 500 - 10 Western Australia 25000 •v. *v 11 Eastern Australia 71371 # # .^^ c^ < ^ 12 Nevif Zealand 44 ^ # •v. 13 Thailand 94 / Hectares .^ Malaysia / U Peninsular 3

15 Kosrae, Federated

States of Micronesia 4 OvervievK Figure 1

16 Indonesia 30000 Relative size-frequency distribution of 538 seagrass polygons in

16 Philippines 978 latitudinal swathe 20-30°S 16 Viet Nam m

17 Japan 495 Notes: The number of polygons is plotted on the pnmary y-axis Ibarsl

18 Korea, Republic of 70 against a logarithmic scale of area. The percentage frequency of each size

19 of Pacihc coast North America 1 000 class IS plotted on the secondary y-axis IdotsI and the mean area of all

20 Western North 374 polygons in each size category is slated at the top of the columns. In this

Atlantic coast of USA swathe there are 180 seagrass polygons of 1 -10 ha in area. In other words

21 Mid-Atlantic coast 292 33 percent of the polygons in this swathe have an average area of 4,84 ha.

of USA In the area calculation it was therefore assumed thai a third of alt points at 22 Gulf of Mexico 19349 these latitudes were each representative of a seagrass area 4.84 ha in size,

22 East coast of Florida 2 800 that 37 percent of points were representative of areas 35 7 ha in size, etc.

23 Mexico 500

23 Belize 1500 within the depth range of most seagrasses, although 23 Curacao 8 for large parts of the globe , substrate

23 2 characteristics and other factors reduce this area of 23 Tobago 1 potential seagrass. In reality, seagrasses occupy only a 23 Martinique 41 fraction of the world's nearshore waters. If the total

23 Guadeloupe 82 area of seagrasses is less than 10 percent of the 23 Grand Cayman 25 shallow water area of the worlds continental shelves, 24 Brazil 200 then the maximum area would be 500000 kml This 24 Chile 2 upper limit incorporates many assumptions and is

24 Argentina 1 likely to be an overestimate. Many of the authors of the subregional and

Note: Almost certainly an underestimate in most cases. national chapters of this World Atlas of Seagrasses have either summarized the existing seagrass maps for

their area or consulted expert opinion to produce the use of mapped data to develop a more direct estimates of seagrass coverage. Further details are

calculation. In many studies, elements of botti provided in the relevant chapters but these totals are

approaches have been combined. summarized in Table 4.

Using a simple modeling approach, the total area These chapters document some 164000 km' of of continental shelf (coastal waters to a depth of 200 m) seagrass but as these cover a limited geographic area

worldwide has been estimated at almost 25 million and a subset of known locations they cannot be used to km"'°'. Assuming a constant slope, this estimate would generate a global area. imply an area of approximately 5 million km' of benthos The World Seagrass Distribution Map, developed

Ml The distribut ion and status of seagrasses 15

on a GIS, is now the most comprehensive map of global large and important seagrass meadows and should be seagrass occurrence m existence. Using this we have factored into any calculation of area. V/e have begun to explore the direct calculation of global experimented with methods of using the polygon data seagrass area. to estimate the seagrass area of these points by The World Seagrass Distribution Map dataset calculating logarithmic size-frequency distributions of includes more than 37000 polygons and some 8800 polygon data in 10-degree latitudinal swathes.

points. A total area of 124000 km'' is clearly defined by The distribution was then applied to the points within the polygons but these provide only partial geographic the swathe, generating an estimate for total seagrass coverage from a few areas which tend to be well l^nown. area (Figure 1). Very small polygons, from data derived Point data represent seagrass areas where habitat from remote sensing (these small polygons tend to be maps are not available. Though more poorly l

Overview Table 5

Functions aniJ values of seagrass fronn the wider ecosystem perspective

Function Ecosystem values

Primary production - including Seagrasses are higfily productive, and play a critical role as food for many herbivores (manatee, dugong,

benthic and epibenthic production turtles, fish, waterfowl, etc.l This productivity lies at the base of the food chain and is also exported to

adjacent ecosytems.

Canopy structure The growing structures of seagrasses provide a complex three-dimensional environment, used as a

habitat, refuge and nursery for numerous species, including commercially important fish and shellfish.

Epiphyte and epifaunal substratum The large surface area of seagrass above-ground biomass provides additional space for epiphytes and

epifauna, supporting high secondary productivity.

Nutrient and contaminant filtration Seagrasses help to both settle and remove contaminants from the water column and sediments, improving

water quality in the immediate environment and ad|acent habitats.

Sediment filtration and trapping The canopy of seagrasses helps to encourage settlement of sediments and prevent resuspension, while

the root systems help to bind sediments over the longer term, improving water quality and in some places

helping to counter sea-level rise.

Creating below-ground structure The complex and often deep structures of the seagrass roots and rhizomes support overall productivity

and play a cntical role in binding sediments.

Oxygen production The released from photosynthesis helps improve water quality and support faunal communities in

seagrasses and adjacent habitats.

Organic production and export Ivlany seagrass ecosystems are net exporters of organic materials, supporting estuarine and offshore

productivity.

Nutrient regeneration and Seagrasses hold nutrients in a relatively stable environment, and nutrient recycling can be relatively

recycling efficient, supporting overall ecosystem productivity

Organic matter accumulation Along with sediments the organic matter of roots, rhizomes and even leaves can remain bound within the

sediment , or accumulate on adjacent coastlines or other habitats, building up the level of the

benthos and supporting other food webs.

Wave and current energy By holding and binding sediments, and by preventing the scounng action of waves directly on

dampening the benthos, seagrasses dampen the effects of wave and current energy, reduce processes of erosion,

reduce turbidity and increase sedimentation.

Seed production/vegetative Seagrasses are capable of both self-maintenance and spreading to new areas via sexual and asexual

expansion reproduction. Recovery following storms, disease or human-induced damage can be relatively rapid.

Self-suslaining ecosystem The complex community of the seagrass ecosystem supports important biodiversity and provides trophic

interactions with other important ecosystems such as coral reefs, mangroves, salt marshes and shellfish

reefs.

Carbon sequestration As perennial structures, seagrasses are one of the few manne ecosystems which store carbon for

relatively long penods. In a few places such carbon may be bound into sediments or transported into the

deeper oceans and thus play an important role in long-term carbon sequestration.

Source: Derived from Short e( a(,°" and Global Seagrass Workshop recommendations. 16 WORLD ATLAS OF SEAGRASSES

enormous areas (e.g. the global National Geographic

Overview Table i "Coral World" map], were excluded from this analysis

Summary of the goods and services provided by seagrass to avoid serious under- and overestimates respectively.

ecosystems When combined with polygon data this method

generates an estimate for the global coverage of

Commercial and artisanal fisheries"^' seagrass of 177 000 km' (using median polygon areas

Finfish (snappers, emperors, rabbitfish, surgeonfish, reduced the estimate by A percent). It is based on the tlounderl™ most comprehensive dataset on seagrass distribution

Mollusks Iconch, oysters, mussels, scallops, clamsl'™ to date. However it is necessarily and unavoidably

Crustacea (shrimp, lobster, crab]" based upon a number of crude assumptions and is

'" Mammals and reptiles (dugongs, manatee, green turtle!'" intended to be no more than indicative of the global

extent of seagrass. In any event, even the 177000 km' Nursery habitat for offsliore fisheries""' is an underestimate of the actual global seagrass area, Food since for many areas seagrasses have not been

Seeds of Zostera marina used to make flour by Sen Indians"'' documented. Until our knowledge of seagrasses in

Rhizomes of Enhalus used as food in Lamu, Kenya" large areas such as insular Southeast Asia, the east coast of South America and the west coast of Africa Fodder or bedding for animals'""' improves, it is unlikely that a better estimate can

Fiber be generated.

Used in mat weaving, Lamu, Kenya""

Basket making, thatch, stuffing mattresses, upholstery'"' THE VALUE OF SEAGRASSES

Insulation"" Seagrasses are a critical ecosystem: their role in

fisheries production, and in sediment accumulation Packing material'"' and stabilization, is well documented, but there are

Fertilizer and mulch""'"' many other important roles, both in terms of their place

in the ecosystem and their value to humanity. Table 5 Building dikes"" lists a number of the functions of seagrasses from a

Coastal protection from erosion'*"""' wider ecosystem perspective. Seagrasses have a relatively low biomass Water purification compared with terrestrial ecosystems, but have a very Reducing eutrophication and blooms'™ high biomass in relation to planktonic-based marine Removing toxic organic compounds from water column and communities. Figures for average biomass vary sediment'"^" considerably between seagrass species and between Interaction with adjacent ecosystems'"' studies; communities of Amphibolis, Phyllospadix and

Nutrient export'"' Posidonia in particular are noted for their high

Source of food or shelter, as a nursery, resting ground or biomass, the last's enhanced by extensive stem and

feeding ground"' root systems. In contrast, species of Halophila, with

Water column filtration'"' their small petiolate leaves and high turnover rates, rarely achieve high biomass. Maintenance of biodiversity and threatened species'" Duarte and Chiscano"", in a literature review, "' Dugongs, manatee, green turtle'" calculated from nearly iOO samples an average

Carbon dioxide sink'"' biomass for different seagrass species, and by averaging these values derived an average biomass for Cultural, esthetic and intrinsic values'"' seagrass of 460 g dry /m' (above- and below- Places of natural beauty ground biomass combined]. As an estimate of global Recreational value seagrass biomass, such estimates are biased towards Educational value large seagrass species. Taking these factors into

account, the median biomass statistic of 205 g dr^ Stabilizing sediments weight/m^ also from data in Duarte and Chiscano, may Binding function of roots'"' be a more accurate reflection of the typical biomass for Role of shoots in reducing surface flow and encouraging seagrass communities worldwide. settlement'"™ In terms of productivity, Duarte and Chiscano""

estimated an average net primary production of about

Source: Various sources - see references by entries 1012 g dry weight/mVyear. Even allowing for overestimation, such figures are very high for marine The distribution and status of seagrasses 17

communities, with the same source citing productivity Mitigating climate change figures for macroatgal communities of 1 g dry The role of the worlds oceans in removing carbon weight/mVday and of phytoplankton of 0.35 g dry dioxide from the atmosphere is still being investigated weight/mVday. and remains poorly understood. It appears that The high productivity and biomass of seagrasses biological processes in the surface layers of the world's are an integral part of many of their uses and values oceans are one of the few mechanisms actively from a human perspective. A broad sample of the removing carbon dioxide from the global carbon goods and sen/ices provided by seagrasses is shown in cycle'"'. Within these processes, seagrasses clearly

Table 6, while further information on a number of these have a minor role to play, although their high is given in the text, both here and in many of the productivity gives them a disproportionate influence on regional and national chapters. primary productivity in the global oceans on a unit area basis, and they typically produce considerably more Fisheries organic carbon than the seagrass ecosystem Seagrass ecosystems are highly productive and also requires'""'. Any removal of carbon either through have a relatively complex physical structure, thus binding of organic material into the sediments or providing a combination of food and shelter that enables export into the deep waters off the continental shelf a high biomass and productivity of commercially represents effective removal of carbon dioxide from the important fish species to be maintained" '". Seagrasses ocean-atmosphere system which could play some role also provide an important nursery area for many in the amelioration of climate change impacts. species utilized in offshore fisheries and in adjacent habitats such as coral reefs and mangrove forests. In Maintaining biodiversity and threatened species most cases, the association between commercially The concept of seagrasses as high-diversity marine important species and seagrasses is not obligatory; the ecosystems has often been overlooked, but this role same species are found in other shallow marine has already been briefly outlined above. Seagrasses habitats. There are, however, a number of studies which also play a role in safeguarding a number of threatened clearly show the higher biomass of such species species, including those such as sirenians, turtles and associated with seagrasses as compared with adjacent sea horses, which are widely perceived to have very unvegetated areas'^l high cultural, esthetic or intrinsic values by particular groups. The wider functions of biodiversity include the Sediment stabilization and coastal protection maintenance of genetic variability, with potential Seagrasses are the only submerged marine photo- biochemical utility, and a possible, though poorly trophs with an underground root and system. understood, role in supporting ecosystem function and

This below-ground biomass is often equal to that of the resilience. above-ground biomass, and can be considerably more e.g. Posidonia"". The role of these roots and rhizomes in Economic valuation binding sediments is highly important, as has been There have been very few studies of the direct illustrated in a number of studies that have compared economic value of seagrasses. In Monroe County, erosion on vegetated versus non-vegetated areas Florida, the value of commercial fisheries for five during storm events. The role of seagrass shoots in this species which depend on seagrasses was estimated at fisheries, process is also important, as these provide a stable US$48.7 million per year, whilst recreational surface layer above the benthos, baffling currents and as well as the diving and industry in that therefore encouraging the settlement of sediments and county, contribute large sums to the economy and are inhibiting their resuspension'"'. also indirectly dependent on seagrasses'"'. Costanza et a/."" calculated a global value of Water purification and nutrient cycling annual ecosystem services for "seagrass/algae beds" By enhancing processes of sedimentation, and through of US$19004 per hectare per yean With their estim- the relatively rapid uptake of nutrients both by ated total area for these combined ecosystems of seagrasses and their epiphytes, seagrass ecosystems 2000000 km' they calculated a global annual value of remove nutrients from the water column. Once US$3801 000000000 li.e. US$3.8 trillion], based removed these nutrients can be released only slowly almost entirely on their role in "nutrient cycling", through a process of decomposition and consumption, which is only one of many values of the ecosystem. The quite different from the rapid turnover observed in same source gives no value to seagrass/algae beds for phytoplankton-dominated systems. In this way food production. seagrasses can reduce problems of eutrophication and Further information is needed to demonstrate the

bind organic pollutants'^'. full economic value of seagrass ecosystems worldwide. 18 WORLD ATLAS OF SEAGRASSES

populations which live disproportionately along the coasts. Such conditions threaten seagrass ecosystems

and have resulted in substantial loss of many seagrass

areas in the more populated parts of the world, as well

as degradation of much wider areas over the last 100 years. A number of natural threats to seagrasses have been recorded. Geological impacts may include

coastal uplift or subsidence, raising or lowering beds

to less than ideal growing conditions. Meteorological impacts can also affect seagrasses: major storm

events in particular may remove surface blomass and even uproot and erode wide areas of shallow water Finally there are biological impacts. Typically these

are part of the ongoing processes in seagrass

ecosystems, such as grazing by fish, sea urchins, sirenians, geese or turtles; they also Include

disruption to the sediments by burrowing animals or

foraging species such as rays. It is rare that such

activities should disrupt seagrass beds over large areas. Diseases, however, represent an important biological impact which can have very widespread effects. The eelgrass wasting disease recorded from

the North Atlantic in the 1930s'"'" was caused by the slime mold Labyrinthuia zosterae"'™. This wasting disease continues to occur and remains a threat to

Damage to seagrass beds caused by yachts in Jersey, eelgrass in the North Atlantic'™'. Similarly in Florida

Islands, UK Bay, disease caused by Labyrlnthula sp. has been

implicated in an extensive seagrass die-off"".

It will be important not only to measure direct value Human threats to seagrasses are now

from activities such as fisheries but also Indirect values widespread. Many result in direct destruction of these

associated with various functions liable 51 including habitats. Dredging to develop or widen shipping lanes

maintenance of water quality and protecting coastlines. and open new ports and harbors, and certain types of

In many ways dollar values provide only a part of the fishery such as benthic trawling, have led to losses of

true picture of the value of an ecosystem, and it is wide areas of seagrass. Boating activities frequently Important to consider other possible means to quantify lead to propeller damage, groundings or anchor value, including employment, protein supply or even damage, often increasing sediment resuspenslon or

quality of life as alternative measures which address creating holes and Initiating "blow-out" areas In

value from a human perspective. It should be noted that seagrass beds. Construction activities within coastal even when dollar values are estimated they do not waters have sometimes led to losses; land reclamation

represent the entire worth of the ecosystem and in no IS a clear example, as is the construction of aquaculture

way constitute a purchase value. ponds in some areas. Even the construction of docks and piers can lead to some direct losses, and to further THREATS TO SEAGRASSES losses arising from shading or fragmentation of The global threats to seagrasses have received seagrass beds. The alteration of the hydrologicat

considerable attention from a number of authors (e.g. regime as a result of coastal development and the

Short ef a/."", Phillips and Durako"'', Short and Wyllie- building of sea defenses can also Impact seagrasses. Echeverrla"", Hemminga and Duarte"'] and their There are examples of direct and deliberate removal of

efforts are only summarized here. In many cases it seagrasses, for example to "clean" tourist or

seems likely that declines In seagrass areas have been to maintain navigation channels.

the result not of Individual threats but a combination of In addition, many seagrass beds have been

impacts. Typical combined impacts may include in- affected by the indirect impacts of human activities. creased turbidity, Increased nutrient loads and direct Land-based threats include Increases of sediment

mechanical damage. Seagrasses exist at the land-sea toads: higher turbidity reduces light levels, while very margin and are highly vulnerable to the worlds human high sedimentation smothers entire seagrass beds. The distribution and status of seagrasses 19

Similarly, while seagrasses can assimilate certain Caulerpa taxifolia, released into the Mediterranean in levels of nutrient and toxic pollutants, high levels of the 1980s, has smothered and killed wide areas of increased nutrients from sev\/age disposal, overland seagrass beds. In 1999, the same species was first runoff and enriched groundwater discharge can reduce observed off the coast of California and could have the seagrass photosynthesis by excess epiphytic over- same impact there""'. growth, planktonic blooms or competition from Climate change represents a relatively new threat, macroalgae. Toxins can poison and kill seagrasses the impacts of which on seagrasses are largely rapidly. Another indirect threat comes from the undetermined"". Potential threats from climate change introduction of alien or exotic species. The alga may come from rising sea levels, changing tidal

Overview Table 7

Summary of marine protected areas WPAsl that contain seagrass ecosystems, from the UNEP-WCMC Protected Areas Database

Country or territory Number of sites Country or territory Numbe r of sites

Anguilla Monaco 1

Antigua and Barbuda Mozambique 8

Australia 11 Antilles Bahamas Nicaragua

Bahrain Patau

Belize Panama

Brazil Papua New Guinea

British Indian Ocean Territory Philippines

Cambodia Puerto Rico

Canada Reunion

Cayman Islands Russian Federation

China Saint Lucia

Colombia Saint Vincent and the Grenad nes

Costa Rica Saudi Arabia

Croatia Seychelles

Cuba Singapore

Cyprus Slovenia

Dominica South Africa

Dominican Republic Spain

France Tanzania 10

French Thailand Germany Tonga

Guadeloupe Trinidad and Tobago Guam Tunisia

Guatemala Turks and Caicos Islands

Honduras

India

Indonesia United States 31

Israel United States minor outlying sland

Italy Venezuela

Jamaica Viet Nam

Kenya Virgin Islands (British) 5 5 Korea, Republic of Virgin Islands lUSI

Madagascar

Malaysia 13

Martinique

Mauntania Note; Few of these sites are managed directly to su pport seagrass

tt most Mauritius protection, and in many cases they do not protect e

Mexico important areas of seagrass in a region. WORLD ATLAS OF SEAGRASSES

regimes, localized decreases In salinity, damage from regional scales. Unfortunately the cost is high and rates

ultraviolet radiation, and unpredictable impacts from of Improvement are low.

ctianges In tfie distribution and intensity of extreme fulore practical protection, although only localized

events. In contrast there could be Increases In in effect. Is the establishment of marine protected productivity resulting from fiigher carbon dioxide areas (ivIPAsI, legally gazetted sites where certain (but concentrations"". by no means alll human activities are controlled or Various studies have attempted to quantify the prohibited in order to provide some protection of

decline of seagrasses, although It must be accepted marine resources or to promote sustainable fisheries. that seagrasses have been degraded or lost over vast Whether out of direct Interest or as an indirect areas without any knowledge of their existence. Short beneficiary, seagrass habitat is present in an and Wyllle-Echeverria'" "' provide an analysis of increasing number of sites in the expanding MPA seagrass losses from reports worldwide. They found network. The total number of I^PAs has Increased

that a loss of 2900 km' of seagrass was documented dramatically In recent years, from less than 500 MPAs between the mid-1980s and the mid-1990s, and they worldwide in 1960 to more than 4000 by 2001 (UNEP-

extrapolated likely seagrass losses over that time WCMC data, but note that this figure includes intertidal

period alone of up to 12000 km' worldwide. as well as subtidal sitesl. No MPAs have been designated solely for the protection of seagrasses; PROTECTING SEAGRASSES however seagrasses are often one of a list of key The dramatic and accelerating declines In seagrass habitats singled out when sites are recommended for areas worldwide are mirrored In other coastal protection (e.g. the Great Barrier Reef Marine Park in ecosystems such as mangroves and coral reefs'^"'. Australia). Many other sites Include seagrasses even Concerns about these declines have prompted some when the key natural resource behind their protection

Increase In efforts to protect these ecosystems. may be something else, such as a coral reef. In the

Perhaps the most valuable protection measure is the majority of MPAs, seagrasses are not acknowledged or

wholesale reduction of the full suite of anthropogenic directly protected. With increased awareness, MPA Impacts via legislation and enforcement at local and boundaries and protection could be expanded to Incorporate adjacent seagrass habitats (e.g. Florida Bay adjacent to the Everglades]. 250 500 UNEP-WCMC maintains a global database on MPAs on behalf of the lUCN World Commission on — Number of sites jiiiiiilll! (left-hand scalel Protected Areas. Linked to the current work, a list of ^M Tuldlditfdpiulecleil, the areas which are known to contain seagrass habitat thousand km' has been prepared and is presented In Appendix 2. A (right-hand scalel Information is provided in Table 7. 150 ^"^ summary of this II m Worldwide there are some 247 MPAs known to

include seagrasses. These are located In 72 countries 100 200 and territories. These numbers are likely to be conservative: seagrasses may well occur at a site but

not be recorded, or not be listed in literature which 50 100 f has been used to develop this database. Even so. It

seems likely that this list is far smaller than the equivalent network for coral reefs (more than 660'°'!

. ^=::::-ii 1 ^,— 1 and mangrove forests (over 800, unpublished data 1900 10 20 30 40 50 60 70 )0 90 2002 20001 and clearly does not present any form of global

Overview Figure 2 network. Added to this must be the recognition that

Grov^th of marine protected areas which include seagrass the vast majority of these sites do not provide any

ecosystems, shown both as the number of sites llinel and the total clear protection for seagrasses - their Inclusion

area protected (shaded areal within MPAs is largely fortuitous.

Figure 2 shows the increase in seagrass MPAs

Notes: The total area statistics are for the entire MPAs, there is no over the past century. It should be noted that the area

Intormation on the area of seagrass within these sites but it Is likely to be figures (shaded areal are a measure of the total area

only a small fraction of the total area. Figure 2 covers only those sites for covered by these MPAs. At the present time It Is

which a date of designation has been recorded. In addition to the 205 sites Impossible to determine the area of seagrasses within

shown here there are a further 42 with a total area of some 3 500 km' these sites, although It Is likely to be only a very small

whose year of designation Is not known. fraction of the total area. It should further be noted that The distribution and status of seagrasses

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^1 The distribution and status of seagrasses 23

designation as "protected" covers a broad range of types of protection, botfi in terms of legal status and practical application of that status. Some sites, such as the National Estuarine Research Reserves in the United States, do not provide any direct habitat protection under their supporting legislation. In many other cases, even where the legislation may provide a formal safeguard, management may be inadequate. The worlds largest MPA, Australia's Great Barrier Reef

Marine Park, has made some efforts to prevent trawling in seagrass areas, but this entire park, like most others worldwide, is still subject to influences from beyond the park boundaries.

In a recent analysis by regional experts, manage- ment effectiveness was considered for some 3'12 MPAs in Southeast Asia and was rated as "good" for only 46 sites 114 percent!"". Finally, many of the threats facing seagrasses come from remote sources, notably terres- trial runoff. Few protected areas currently manage entire watersheds and the legal framework is typically powerless to control nutrient and toxic pollution and sedimentation arising outside an MPA.

In addition to the designation of MPAs, other legal measures have proved beneficial to seagrasses in some The shallow seagrass beds of Montepuez Bay, Mozambique, at low places, although seagrasses themselves are rarely tide. singled out as the object of protection. Such legislation includes restrictions on particular activities such as development. Transplanting cannot be successful trawling, dredging or *he release of land-based sources unless the conditions for seagrass to thrive pre-exist"". of degradation such as sediments and pollutants. For Although widely undertaken In some areas, many example, in Queensland waters (Australia! all sea- transplantation efforts have had low success rates and grasses and other marine plants are specifically transplanting can be quite labor intensive and ex- protected under the Fisheries Act of 1994, for the pensive'"'. Technologies for more uniformly successful protection of commercial and recreational fishing and less expensive seagrass transplanting are evolving, activities. In seagrass is protected and include developing models for site selection'™', under the Native Vegetation Act 1992. In the United advanced methods for transplanting"*' and seeding"", States, seagrass habitats are protected under Section and scientific success criteria"". Restoration of

4041cl of the Clean Water Act from direct dredge and fill seagrasses is now at the stage where technologies are activities without a permit'"'. Although clearly available, but overcoming insufficient water quality important, such legislation is rare, and still insignificant conditions remains the greatest obstacle to seagrass at the global level. restoration worldwide.

In addition to legal protection, public education can play an important role in safeguarding seagrasses, CONCLUSIONS notably via the protection of charismatic seagrass We know a substantial amount about seagrasses in associates such as turtles and dugongs, but also In the many parts of the world, but there remain considerable directing of activities which could impact seagrasses. gaps in our knowledge. As the taxonomies of various Coles and Fortes"" provide a valuable review of species are revised, even our understanding of how methods for direct and indirect protection of many species of seagrass there are will be subject to seagrasses. debate and change.

Seagrass restoration may include both the The range of individual seagrass species is improvement of overall conditions for seagrass growth presented in a new series of maps. By combining these

In an area, such as an improvement in water clarity range maps we are also able to look at biodiversity resulting from decreased runoff or nutrient inputs, as patterns in seagrasses as a whole. The primary well as direct transplanting or seeding of seagrasses"". centers of seagrass biodiversity are identified here as

Sometimes transplanting is mandated as mitigation for insular Southeast Asia, Japan and southwest unavoidable damage to seagrasses incurred in coastal Australia, with additional areas in southern India and 24 WORLD ATLAS OF SEAGRASSES

eastern Africa. While there are some important measures, which include social welfare, health and parallels between seagrasses and the two other major well-being, are difficult to measure. tropical coastal ecosystems of coral reefs and The threats to seagrasses have been widely mangroves, there are also important divergences, considered by other authors and include natural and

notably with the seagrass centers of diversity in Japan anthropogenic causes. The latter appear to have

and in southwestern Australia but also with the increased dramatically in recent years, and include

occurrence of seagrasses in high latitudes as well as direct physical destruction and a range of indirect

the tropics. threats, the most critical being decreases in water

It is clear that, despite the relative paucity of clarity resulting from nutrient and sediment inputs but

seagrass species, as a habitat these communities are also including climate change. In many cases,

in fact highly diverse. There are many thousands of seagrass declines have been linked to multiple

species recorded living in association with seagrass stresses, acting together. In only a few places around communities, although only a small proportion of these the world are measures being taken to address these

are strictly confined to seagrass ecosystems. There is threats. In the present work we have assembled an

an urgent need to develop a more comprehensive assessment of marine protected areas with

understanding of the full range and diversity of life in seagrasses worldwide. Some lUl sites are known to

seagrasses. include seagrass ecosystems. This is a far lower figure The work presented here includes a detailed map than for other shallow marine ecosystems, while

of the known locations of seagrass habitats around the further concern must be expressed about the

world. Once again we are made aware of considerable effectiveness of these sites in protecting seagrasses,

gaps in our knowledge. There is an urgent need for both from direct impacts and from the Indirect impacts

clearer documentation of the existence and location of such as pollution and sedimentation which may be

seagrass ecosystems in western South America and in carried into the seagrass areas from beyond the West Africa, for example. Even within areas of high reserve boundaries.

seagrass biodiversity, in many cases little is known The chapters which make up the bulk of this about the actual distribution of seagrasses. tvluch of work provide a more detailed examination of seagrass

our data for the World Seagrass Distribution Map is distribution and of the various themes considered here. based on individual points of occurrence and not on They provide detailed examples of seagrass com-

area of coverage. The importance of the high levels of munities around the world, and illustrate issues

primary productivity in seagrasses is well known, and relating to distribution, status and management of

these are clearly disproportionate to the total area these beautiful and critically important ecosystems.

covered by these habitats. It would be Invaluable to

develop an accurate estimate of the total area of ACKNOWLEDGMENTS

seagrasses worldwide in order to better analyze the This chapter would not have been possible without the help and input

role that these may play in global and regional from all the participanis at the Global Seagrass Workshop which was held

fisheries, and in climatic and oceanic carbon cycles. In at the Estuarine Research Federation meeting in St Petersburg, Florida

the absence of any better data we have undertaken an in October 2001 . The chapters authors have also drawn heavily on all the

analysis of seagrass area and suggest a conservative chapters written by the regional authors Isee Table of Contents). The

estimate of 177000 km'. assistance provided by Sergio Martins and Mary Edwards is gratefully

There can be no doubt of the value of seagrasses, acknowledged. Jackson Estuarine Laboratory contnbution number 397.

although such values are often overlooked. For fish, many species are not obligatory users of seagrass AUTHORS

ecosystems, but appear to benefit from their presence. M. Spalding, UNEP World Conservation Monitoring Centre, 219

Many others use seagrass ecosystems for a short (but Huntingdon Road, Cambridge, CB3 ODL, UK. Contact address; 17 The

often critical! part of their life histories, and seagrasses Green, Ashley, Newmarket, Suffolk, CBS 9EB, UK. Tel: *« IGI1638

are rarely considered in assessing these fisheries. 730760. E-mail: mark0mdspalding.co.uk Economic evaluations are often constrained by

analytical procedures and many fail to calculate the M. Taylor, C. Ravilious, E. Green, UNEP World Conservation Monitoring

total economic value of an ecosystem. The critical role Centre, 219 Huntingdon Road, Cambridge, CB3 ODL, UK.

of seagrasses in stabilizing sediments, reducing

erosion and even cleaning coastal waters is rarely F Short, University of New Hampshire, Jackson Estuarine Laboratory, 85

accounted for in such analyses. In addition, other Adams Point Road, Durham, NH 0382i, USA.

vCI The distribution and status of seagrasses 25

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\:h Scandinavia and the Baltic Sea 27

1 The seagrasses of SCANDINAVIA AND THE BALTIC SEA

C. Bostrbm

S.P. Baden

D. Krause-Jensen

Scandinavia supports only a small fraction of tfie The Swedish west coast and global seagrass resource; however, tfie first On the Swedish west coast, as well as in Danish waters,

reports on tfie importance of seagrass meadows eelgrass is the most widely distributed seagrass, and for coastal ecosystems derive from tfils area, from dominates sandy and muddy sediments in coastal

Denmark""". Tfiis cfiapter summarizes tfie distribution areas of low to moderate wave exposure. In Denmark, and importance of eelgrass, Zostera marina, in very exposed areas facing the are devoid Scandinavian and Baltic coastal waters. Altfiougfi most of eelgrass. Along moderately exposed Danish and of tfie quantitative Information Is based on research Swedish coasts eelgrass forms extended belts

carried out in non-tidal areas of Denmark, Sweden and interrupted by sandbars, while protected eelgrass

Finland, the approach is holistic, and includes populations generally form more coherent patches. distribution maps and anecdotal information on Due to Its wide salinity tolerance (5-35 psul'", eelgrass eelgrass from Iceland, Norway and the coastal areas of grows in the Inner parts of brackish estuaries and the Baltic Sea, Including Germany, Poland, , sheltered bays and In fully marine waters. In areas of

Latvia and Estonia (see f^ap 1.11. low salinity, Ruppiaspp. and Zostera noltii can co-occur at the Inner edges (0.5-1.5 m depth) of eelgrass. DISTRIBUTION PATTERNS Eelgrass occurs from shallow [0.5-1 ml water Norway down to maximum colonization depths that often match

In the north Atlantic, eelgrass Is found around Iceland, the Secchi depth. In the inner parts of estuaries, the where about 30 sites have been identified since the maximum colonization depth is about 3 m, in outer '". rare 1950s''*'. Eelgrass forms isolated populations on parts 4 m and along open coasts about 5 m"° In shallow exposed and sheltered sandy bottoms along cases of very clear waters, eelgrass penetrates to 1 m the entire Norwegian coast'" and extends Into the White mean sea level (tidal range ±0.1 to O.A ml. Eelgrass Sea. The only Norwegian seagrass paper reports displays a bell-shaped distribution pattern along the eelgrass densities between 50 and 160 shoots/m' and depth gradient, with maximum abundance at canopy heights generally between 15 and 60 cm, intermediate depths and lower abundances in shallow '". of although in extreme cases the length of an Individual and deep water"'' The biomass Danish and plant may exceed 180 cm'". Areas of low density have Swedish eelgrass populations peaks in late summer at the highest canopies. The average biomass lApril- levels reaching above 250 g dry weight/m'. Maximum

Novemberlat the two sites studied was 20 and AO g dry shoot densities range between 1 000 and 2 500 "'""'". scour welght/m^ respectively (range: 12-60 g dry welght/m^ shoots/m^ Exposure, desiccation and Ice water, Figure 1.11 The associated fauna is rich (265 taxa, may reduce seagrass abundance in shallow including mobile macrofauna and epiphytes! and while reductions in seagrass abundance towards the ranges between 5 000 and 10 000 individuals/ml The lower depth limit correlate with light attenuation along

species assemblage Is dominated by six or the depth gradient"'''"'"'. seven families of amphipods, while the epiphytic In southernmost Sweden, eelgrass meadows at 2-4 depth, community is characterized by hydroids. bryozoans and flourish on stony and sandy bottoms m crustose and upright algae'". Consequently, these and may reach densities and standing crops shallow, vegetated sites are of great importance for corresponding to 3 600 shoots/m' and 470 g dry in 1.11''". The young year classes of fish in the Skagerrak area"". welght/m', respectively [site 11 Figure 28 WORLD ATLAS OF SEAGRASSES

Baltic 600 Western Sea and Germany The western Baltic Sea, composed of the Kiel and the

Ivlecklenburger is 500 T''^^'' Bights, a transition zone between marine (North Sea] and brackish (Baltic proper] water J 400 i and shows fluctuations in salinity (generally 10-18 psu CD but occasionally 8-28 psu'""'!. In this region eelgrass

* 300 is found both along exposed sandy and in long, -o _CTt inner bays ("Forden"! and shallow ("", S 200 "Haffs"! with reduced water exchange and muddy substrate""^". Along exposed shores, the upper limit

of distribution is set by wave-induced disturbance. Typically, continuous beds are found from 2.5 m depth ri-lllllll and deeper. Additionally, patchy beds are found Norway Sweden kjGer. Swed. Finland between the sand reefs and the at depths of 1- •$'?' <* ^

of 8 m, and there is an almost continuous belt of eelgrass all along the shoreline, although on gravel- and stone-dominated substrates plants are rare.

Extended populations are found m Orth Bay, in Kiel Figure 1.1 Fjord (Falkenstem! between Travemunde and

Average 1+1 SEl above-ground biomass values Ig dry weight/m'l Klutzhoved, in the Wismar Bay and north of

for eelgrass [Zostera marina] along the Baltic Sea coastline Peninsula"". Zostera noltii has been reported from |>1 500 km] Schleimunde, Heiligenhafen, Wismar Bay and Lagoon"". "'". Source Various sources"- In the Kiel area (Belt Sea] the eelgrass growing

period IS approximately 210 days, and growth is initiated

Oresund area between Denmark and Sweden (sites 8- in June, peaks in August-September and stops in 10 in Figure 111 also supports well-developed eelgrass March. Shoot lengths range between 20 and UOcm'™"'.

meadows at 1.5-6 m depth'''^ In September 2000, four In Kiel Fjord (Friednchsort and Moeltenort), eelgrass

eelgrass sites along this 100-km coastline showed the density is 600-1 600 shoots/m''"'". The biomass range in

following features: coverage: 20-80 percent; density: Kiel is 450-600 and 200-800 g dry weight/m' on 293-1 573 shoots/m'; above-ground biomass: 69-193 g mud and sand, respectively, and the daily production is dry weight/m': shoot length: 25-125 cm; and shoot 1.5-2.2 g carbon/m"™'. In the 1970s, the mean annual

width: 0.2-0.5 cm'"'. eelgrass standing stock for two sites in Schleswig- There are qualitative and quantitative data on the Holstem (Kiel Bight] was 42.5 metric tons/ha"".

leaf fauna Idefined as the sessile and motile fauna A typical feature of shallow (depths of 1-3 m]

living on the leaves], mobile epifauna (intermediate eelgrass beds is their co-occurrence with blue mussels

predator invertebrates and fishi and piscivore fish [MytUus eduiis], which represents a facultative (secondary predators! from the Swedish west mutualism""'. Isopods [Idotea spp.] and snails coast"'''". Data on infauna are more scarce'" '*'. Due to {Hydrobia spp., Littorina spp.! are abundant grazers, the high organic content of most western Swedish and remove eelgrass biomass and epiphytes,

seagrass beds l2-2i percent ash-free dry weight], the respectively, highlighting the importance of biological

infauna (40-130 000 individuals/m'l is dominated by interactions, which may locally override the negative

polychaetes and nematodes. The leaf fauna is symptoms of eutrophication'"^". In shallow lagoons

dominated by tube-building amphipods, mainly (e.g. Schlei Estuary!, eelgrass is also consumed by

detritivores and suspension feeders (80-250 000 birds, especially mute swans ICygnus olor]. mdividuals/m-j, whereas the abundance of herbivores IS low. Shrimps and crabs make up 90 percent of the The Swedish east coast

mobile epifauna, and fishes constitute only about 10 Eelgrass penetrates into the brackish (0-12 psu] Baltic

percent of the intermediate predator abundance (30- Sea, and is common in most coastal areas. The northern

160 individuals/m', with maximum abundances in late and eastern distribution limits of eelgrass correlate with

summer!. The piscivore fishes (eelpout, cod and the 5 psu . The usual depth of eelgrass in the

salmon] are few during daytime""'. Faunal communities Baltic Sea is 2-4 m (range 1-10 ml. Zostera noltii extends

of Danish eelgrass beds are similarly rich, but have to southern Sweden, and to Lithuania in the eastern

received little attention since the 1960s"" and 1970s'"'. Baltic'"'. At present, the northern limit of Zostera noltii in E J

Scandinavia and the Baltic Sea 29

20" '0'^ E 30- E N ;.'g: ^v A

."-'

\

'i SORTH V-. it.l II iiirt '' Sli.l

y" \. FINLAND

"" ^;. NORWAY ""/;;, ^P"'

60' ^ Archipelago Aland i^y'" ..^''-

'ji^ • SWEDEN '. ^V . V^-Jj^ 1- III la II ' ^ Hanko Pwiinviib siortIMm KlauvaJ .1 Gullmarsfjoia MtC ' _ ESTONIA

Knslansand |S> skafl6 -^ it, Y /'V r ,

Uiilfiil VaslacviK Limljwden lliau .- " i.. ,^ •Vendelsofjord _ tiolland

• Kalma-sund.f ^ DENMARK^ . j,|^„j * Landskrofia

(. in iiiiiwi » J < Fredshog },i,il * Sandhammaren LITHUANIA HV^^ T» « 'lin^iiihl •** ^T /X* y!^ Ltomholm f,i,kL.i,:ixii, , >.v/ fiit^H- V ZinjiM I'uimMib ^^^^^ i . ^- Oril, Riigen .;l „/ Heillgenhafen (^ • •. • '.•«„,* " ,L,,,„„„ 100 150 200 250 KilometefS POLAND ^^^ Mecklrnhun^er Biglil ' GERMANY ^^^

Map 1.1

Scandinavia

the Baltic Sea is unknown. Due to lack of tides, all unpublished data by S. Tobiasson. Dense shallow stands seagrass beds in the Baltic Sea are permanently have short (20 cm], narrow (2-3 mml leaves and usually submerged, and often mixed with limnic angiosperms grow in mixed stands with Potamogeton pectinatus,

le.g. Potamogeton spp. and Myriphytlum spp.l. Ruppia maritima, palustris and On the brackish 16-8 psul east coast of Sweden, the bladderwrack Fucus vesiculosus, while the deepest

most extensive eelgrass meadows are probably found in stands are sparse, monospecific and have longer (>80 the sandy Kalmarsund-Oland. Along the southeastern cm] and broader (5 mml leaves. coast of Sweden (Sandhammaren to VastervikI, eelgrass The coverage pattern is usually patchy (patch area

is common on sandy bottoms with good water exchange. 10-50 m^ with a mean coverage of 50-75 percent, range

The demographic information from this area is based on 5-100 percent). At the main distribution depth, the mean anecdotal evidence, diving observations made during shoot density is 500-600 shoots/m^ but ranges between

coastal monitoring (University of Kalmarl, and 100 and 1 0^0 shoots/m'', depending on depth. The 30 WORLD ATLAS OF SEAGRASSES

Figure 1.2 are mainly controlled by physical factors (Figure 1.21. In

Aerial photographs of two typical exposed eelgrass [Zostera tfie Arcfiipelago Sea, eelgrass beds are found towards

marina] sites at the Hanko Peninsula, southwest Finland, northern the leeside of islands, while nnore sheltered, inner bays

Baltic Sea (adjacent to site 16 in Figure l.ll on the mainland do not support eelgrass beds.

Eelgrass sites in Finland vary in terms of patch size (1- 75 m'l, shoot density (50-500 shoots/m'l, shoot length

[20-100 cml, biomass [10-32.1 g ash-free dry weight/m'"" and sediment properties (organic content 0.5-1.5 percent, 0.125-0.5 mm). The low

shoot densities result in low areal production rates [138-523 mg dry weight/ mVday""]. The associated

fauna of Finnish seagrass beds is well described"'''. A rich sedimentary fauna (25 000-50 000 individuals/m^ 50 species'""' and a distinct leaf fauna'"""')

contributes significantly to coastal biodiversity in Finland. Northern Baltic seagrass communities lack crabs and , and the nursery role for

a. Kolaviken |59°49'N, 22°59'E!: the high-energy regime at this site economically important fish species is limited, but

is reflected in a complex, patchy bed structure. seagrass beds serve as feeding grounds for fish.

HUMAN USE OF SEAGRASSES \JM^:^0^ The direct use and manufacture of eelgrass-based materials has been local and intermittent. In Denmark and other countries dried eelgrass leaves have been used as fuel, packing and upholstery material, insulation and roof material, feeding and bedding for domestic

, fertilizer and as a resource to obtain salt"""'.

In Sweden, dried eelgrass leaves have mainly been used for insulation of houses. Historically, the abundant

eelgrass resources of the sheltered lagoons in the

western Baltic Sea (Germany) have been utilized for

upholstery and insulation. The last eelgrass collector at

Maasholm, Germany, retired in the 1960s, In the

b. Ryssholm (59°60'N, 23°05"E): the continuous eelgrass bed is southeastern Baltic Sea, human communities on the

interrupted by sandbars, while circular to highly irregular, Curonian [Lithuania) used eelgrass as upholstery

elongated patches are found at the outer edge of the bed. material before the Second World War, indicating

abundant eelgrass meadows in the area before the

Notes: The areas covered by eelgrass in [al and [bl are 23 and 6 hectares, 1940s'''™. The current appreciation of seagrasses

respectively The depth range covered by eelgrass is approximately 2-6 m. primarily concerns the services that seagrasses provide

to the overall functioning of coastal ecosystems in terms

above-ground biomass may exceed 100 g dry weight/m' of enhancing biodiversity, providing nursery and foraging (site 13 in Figure 1.1). The steep, exposed coastal areas areas for commercially important species, improving of southern Sweden (Skanel and the east coast of the water quality by reducing particle loads and absorbing Oland Island lack eelgrass"". The semi-exposed sandy dissolved nutrients, stabilizing sediments and

shores of Gotland Island support extensive eelgrass influencing global carbon and nutrient cycling'^".

meadows. The northern limit of distribution is in the northern Archipelago of Stockholm'"'. Few studies of the HISTORICAL AND PRESENT DISTRIBUTION associated fauna have been carried out'^ but these Norway

meadows support more than 20 infaunal species and a Along the southeastern coast of Norway (between the rich leaf fauna with over 30 species"". Norwegian-Swedish border and Kristiansand), almost

100 sites have been monitored since the 1930s in Finland and Aland Islands connection with beach seine surveys each autumn

In Finland, eelgrass grows exclusively on exposed or [September-October) by the Institute of Marine moderately exposed bottoms with sandy sediments. Research'". The presence of vegetation has been The spatial patterns of eelgrass beds in shallow water estimated by aquascope, and seagrass cover has been Scandinavia and the Baltic Sea 31

divided into the following categories: 1 = no vegetation, 2 Figure 1.3 = few plants. 3 = some plants, 4 = many plants, 5 = Norwegian eelgrass coverage

bottom totally covered. Unfortunately, only a small fraction of ttiis dataset has been compiled and most is

unpublished. The general impression, however, is that the coverage of eelgrass increased during the 1930s, and since then it has varied irregularly IFigure 1 .3 a, bl. Some areas showed signs of reduction in the late 1960s, and apparently there was a reduction probably indirectly

related to the great bloom of Chrysochromulina in 1988. Now the coverage seems generally to be good'"'.

1933 40 50 60 70 80 90 2000 The western and eastern coasts of Sweden

During the 1980s inventories of the shallow coastal a. Long-term trends in the presence of eelgrass [Zosiera marina] areas including eelgrass were carried out along the at shallow, soft-bottom sites assessed by aquascope in

Swedish west coast as a basis for coastal zone southeastern Norway (Kristiansand to the Norwegian-Swedish management. In 2000, a revisit and inventory of 20 km' of borderl during the period 1933-2000. eelgrass meadows in five coastal regions along 200 km of the Skagerrak coast was carried out using the same 5 methods laquascope) as during the 1980s, but mapping Monotypic Zostera marina accuracy was improved by using the global positioning 4 system (GPSI. This study showed that areal cover had decreased 58 percent (with regional variations) in 10-15 2 3 "'s^Yv^^ D^V years. In the 1980s, eelgrass covered about 20 km"' of f--- Mixed Zostera marina bottom along this 200-km section of the west coast, ^ while only about 8.4 km' was present in 2000"". Since

1994, one eelgrass site in southwest Sweden near 1

Trelleborg (site 1 1 in Figure 1.11 has been included in the 1933 40 50 60 70 80 90 2000 local coastal monitoring program. Shoot density and biomass of eelgrass at this site has increased b. Coverage at sites where eelgrass occurs in single stands (green significantly since 1994 (linear regression for biomass; linel and mixed with benthic algae (black linel. p<0.001, r = 0.811, and this positive trend seems to be true for many of the eelgrass monitoring sites in the Notes: 1 = no coverage, 5 = bottom totally covered. Number of sites

Oresund region (sites 8-11 in Figure 1.1''"'l probably due sampled each year 138-134, mean 931 vary due to variation in vraler to greater exposure and/or invertebrate grazing''". No turbidity. No data obtained dunng 1940-44. estimates of the total area covered by eelgrass along the whole Swedish west coast (>400 kml exist. An estimation Source: Norwegian Institute of Manne Research"". of the total eelgrass coverage along the southeastern

Swedish coast (including the Oland Islandl yields weight'^'. In the 1930s, wasting disease led to substantial minimum and maximum numbers between 60 and 130 declines in eelgrass populations, especially in northwest km', respectively'"'. Between this region and the Denmark where salinity is highest (Figure 1.4'"'l. In 1941, northern distribution limit in the Stockholm Archipelago eelgrass covered only 7 percent of the formerly eelgrass is still common, but far less abundant due to vegetated areas, and occurred only in the southern, most lack of suitable substrate'^". brackish waters and in the low-saline inner parts of Danish estuaries (Figure 1.4'"' ^^'1. No national Dennnark monitoring took place between 1941 and 1990, but

In Denmark, records of eelgrass distribution date back to analyses of aerial photos during the period from 1945 to around 1900, and provide a unique opportunity to the 1990s show an initial lag after the wasting disease describe long-term changes. In 1900, eelgrass was followed by marked recolonization in the 1960s''''"'. widely distributed in Danish coastal waters, and covered Today eelgrass again occurs along most Danish approximately 6 726 km' or one seventh of all Danish coasts but has not reached the former areal marine waters (Figure 1.4"'^'l. The standing crop ranged extension'^'^". Based on comparisons of eelgrass area between 270 and 960 g dry weight/m', in sparse and distribution in two large regions, Oresund and dense stands, respectively, and total annual eelgrass Limfjorden, in 1900 and in the 1990s, we estimate that production was estimated at 8 million metric tons dry the present distribution area of eelgrass in Danish 32 WORLD ATLAS OF SEAGRASSES

Figure 1.4

Map of eelgrass area distribution in Danisli coastal waters in 1901, 1933, 1941 and 1994 North Sea -< 1 1901 A'or/Zi 5ea -^ '^ 1933

>, ^S Sweden Sweden 1 A^' n

—L ^^"^> ---'- X' Kattegat .^ Kattegat 1 I > Denmark Denmark ff^ ?&^ yUr^und ""rk^ V^ "^^^ * \ Baltic Sea Baltic Sea ^%t^^h K ) German^^^ /^ 1^^ Cb

A'onA Sea 1994

^| Sweden /^5^i4- t:3f% -^A ^ * \ Kattegat \ ~ Denmark \^' yT !* ^?ia M "^^>-\ S ** ^'^ 3 Baltic Sea (n •t'^ in P V^*\ Germany A

Notes: Darl( green areas indicate liealthy eelgrass while black areas (on ttie 1933 rnapl indicate where eelgrass was allected by the wasting disease but

still present in 1933. The arrow shows the location of Limfjorden.

Source: Various sources: 1901 (redrawn'"!, 1933 (redrawn'"'!. 1941 (redrawn'^^'! and 1994 (coarse map based on visua( examination of aerial photos and

data from the national Danish monitoring program, produced by Jens Sund Laursen!

coastal waters constitutes approximately 20-25 percent visited in field surveys, while maps from the 1 990s were

of that in 1900 (Figure 1.4|. The area distribution of based on image analysis of aerial photography. This

eelgrass in Limfjorden was thus estimated at 345 l

in 1900"' and at only 84 l

photography data from the Limfjord counties!. In impoverished light conditions due to eutrophication. In

Oresund, eelgrass covered about 705 l

methodology influence these comparisons since the 1.6!. In the 1990s, colonization depths were reduced by

distribution maps of eelgrass from the beginning of the about 50 percent to 2-3 m in estuaries and 4-5 m in last century were based on extrapolation between sites open waters. —

Scandinavia and the Baltic Sea 33

Colonization depth Colonization depth 12

along open coasts in estuaries • 1900 • 1992 40 "10 40 1900 10 • •, ^ 30 30 ?8

at .. 1. o llli o So llill 1 lillll 1111 • er 1^" o 1997 1997 S 40 io " 2 i Wv' 30 1 30 V9 i'

20 . 20 2 4 6 8 10 12 Secchi depth (ml '" 10 > 1

1 0. . 1 ^ Figure 1.6 2 4 6 8 10 12 2 4 6 8 10 12 Secchi depths and maximum colonization depths of eelgrass Colonization depth Iml patches in Danish estuaries and open coasts in 1900 and 1992

Figure 1.5

Maximunn colonization depth of eelgrass patches in Danish Source: Measured by Ostenfeld'" in 1900 and by the national Danish estuaries and along open coasts in 1900 and 1996-97 monitonng program in 1992.

Source; Based on data from 12 sites in estuaries and 18 sites along open 1998, filamentous green algae [Cladophora glomerata] coasts investigated by Ostenfeld'" in 1900 and by the national Danish dominated along the coast, and eelgrass was nnonitoring program in 1996-97 considered rare and endangered; no eelgrass was found during underwater surveys during 1993-97'^". Germany, Poland and Lithuania

In Germany (Kiel Bightl, eelgrass competes with increasing amounts of filamentous algae, and in some areas the depth distribution of eelgrass decreased from

6 m in the 1960s to less than 2 m at the end of the

1980s"". In the Greifswald Lagoon (island of RugenI, the distribution of eelgrass has remained fairly stable, despite the almost total disappearance of red algal belts during the period 1930 to 1988"''. Nevertheless, eelgrass is by far the most abundant macrophyte on sandy to muddy shores in this area'"'.

In Poland IGulf of Gdansk, Puck Lagoon), abundant eelgrass meadows grew down to a depth of 10 m in the

1950s, but were almost totally replaced by filamentous brown algae and Zannichellia palustris during the period

1957-87'""' (Figure 1.7). The change from dense sea- grass beds to algal-dominated assemblages has caused a shift in the commercially important fish communities. Hence, eel [Anguilla anguiUa] and pike [Esox lucius] have decreased in abundance and have been partly replaced by roach [ ruWusl""". In addition, eelgrass suffers from heavy metal contamination"".

Transplantation of eelgrass has been tested in the Puck Figure 1.7

Lagoon"". Recently natural recolonization has taken Long-term changes in the distribution of eelgrass (Zosfera marina] place in some areas of this lagoon"". in the southeastern Baltic Sea (Puck Lagoon, Poland!

Along Lithuanian coasts in the southeastern

Baltic Sea, eelgrass had virtually disappeared before Notes: Scale bar in lower right corner corresponds to approximately any scientific evaluation was made. Eelgrass most 5 km. Green areas indicate eelgrass cover likely occurred along the 90-km-long sea side of the

Curonian Spit, covering thousands of hectares'*". In Source: Modified after Kruk-DovKgiallo'"'. 3A WORLD ATLAS OF SEAGRASSES

One northern site IPalangal supported eelgrass, detritus may lead to anoxia. High water indicating that eelgrass was probably present formerly also stimulates microbial decomposition rates and along the whole Lithuanian coast'" ''^'. The seagrass thereby further increases the risk of anoxia. Oxygen

literature from and Estonia is scarce, but deficiency in the meristematic region of eelgrass is a eelgrass has been reported to occur sparsely among likely key factor explaining events of mass mortality in

algal-dominated assemblages in the Gulf of Riga'™'. eelgrass beds'" "', possibly in combination with sulfide exposure"". Shallow eelgrass populations often show Finland large and rapid fluctuations, suggesting that stochastic The only long-term analysis of an eelgrass site in interactions between water temperature, light, southwest Finland recorded no change in density and nutrients and physical disturbance like strong wave standing stock between 1968 and 1993"". In 1993, action and ice scouring play important regulating roles,

eelgrass biomass was about 85 g dry weight/m' and and that recolonization may also happen relatively fast

corresponded well with the yearly means for 1968-70 in in deeper water if conditions improve'^'"'.

terms of ash-free dry weight 120 g/m'). By contrast, the Other threats include siltation and mechanical associated eelgrass fauna showed marked signs of damage. For example, the construction in 1995-2000 of eutrophication. Total abundance of infauna had the Oresund bridge between Denmark and Sweden, increased almost fivefold, and the total animal biomass almost 8 km long and one of the most massive marine had more than doubled over 25 years. The number of constructions in Scandinavia, was likely to affect the taxa showed minor changes over time. These faunal large eelgrass populations in Oresund. However, strict changes indicate increased food availability, due to regulations on dredged quantities and spillage during eutrophication. Unfortunately, no long-term data from the construction works prevented detectable negative "'. other Finnish eelgrass sites exist to verify this result. impacts on eelgrass""™

Genetic analysis of Finnish eelgrass meadows suggests In some Danish estuaries where eelgrass and

an age of these plant ecosystems between 800 and 1 600 blue mussel occur in mixed populations, mussel years"'' "', indicating that eelgrass colonization must fishery may constitute a threat to eelgrass

have taken place at present salinities. Those eelgrass populations""'. In Sweden the increasing leisure boat

populations near their limit of distribution in terms of harbors with uncontrolled anchoring, dredging and

salinity were not affected by the wasting disease in the water currents from propellers are the main physical 1930s"" and have also persisted through severe threats to seagrass meadows.

anthropogenic stress and long-term physical stress in

terms of landlift, wind disturbance, sedimentation and The Baltic Sea

fluctuations in temperature and ice cover Based on very As in Denmark and Sweden, the drifting and sessile crude areal estimates, and extrapolations from the forms of fast-growing, filamentous algae constitute a number of known eelgrass sites verified by diving (totally serious threat to seagrasses in other areas of the "'", about 50 sitesl, our guess is that the total coverage of Baltic'" which will probably have negative effects on

eelgrass in Finland is probably less than 10 km'. the whole eelgrass community'"'. During the past ten years, increasing amounts of ephemeral, filamentous THREATS algal mats have been observed at shallow localities in Kattegat and Skagerrak the northern Baltic Sea'" "', with profound negative

Since the lower depth limit of eelgrass is determined by effects on the benthic communities"". In 1968-71

water transparency, eutrophication is a main threat to filamentous algal mats were already common at especially deep eelgrass populations. Maximum Secchi eelgrass sites, but their biomass was less than 5 g ash- depths and colonization depths approached 12 m in free dry weight/m' ""'. Today, the biomass of drifting

open Danish waters in 1900 but rarely exceeded 6 m algae in Finland commonly exceeds 1 000 g dry "' in the 1990s (Figure 1.61. The maximum colonization weight/m'"' and subsequent periodic anoxia is also

depth is also correlated to the of water common in shallow areas. It is clear that these algae are

column nitrogen, which is the main determinant of a major threat to the Baltic Sea seagrass ecosystems. In

phytoplankton biomass in Danish coastal waters'™. the heavy traffic coastal areas of the Baltic Sea, oil spill Eutrophication-gained filamentous algae (mainly accidents could be detrimental to seagrass vegetation. ephemeral) may shade seagrasses, hamper water Other threats include sand suction and construction.

exchange and cause a decline in associated faunal "''"'. communities, e.g. shrimps and crabs'"" In NATIONAL AND SCANDINAVIAN POLICY shallow stagnant waters with limited oxygen pools, as Several political initiatives affect Scandinavian seagrass

well as in deeper stratified waters, the oxygen- populations. In 1987, the Danish Government passed an consuming decomposition of ephemeral algae and Action Plan on the Aquatic Environment including Scandinavia and the Baltic Sea 35

measures on wastewater treatment, the storage of Convention on Biodiversity also place demands for animal manure and reductions of agricultural nitrogen monitoring seagrasses in Scandinavia""*. Mor'; details and phosphorus. The aim was to reduce annual total on political initiatives on nutrient reductions and nitrogen discharge by 50 percent, and that of phosphorus monitoring are summarized in Laane ef ai.'""' (Chapter by 80 percent, within five years. A second action plan 6.21. On the initiative of the Helsinki Commission, a Red containing further measures was passed in 1998 to List of marine biotopes in the Baltic Sea'^" serves as an ensure that the planned reductions of nitrogen and instrument In conservation, management and policy- phosphorus discharges will be in effect before 2003. In making. In the Red List "sublittoral sandy bottoms addition there are several directives concerning point dominated by macrophytes" and "sand banks of the sources and protection of groundwater An sublittoral photic zone with or without macrophyte announcement on mussel fishery in Denmark prohibits vegetation" are classified as "heavily endangered" and fishery at water depths shallower than 3 m in order to "endangered", respectively'^". Accordingly, during the protect eelgrass beds. A nationwide Danish monitoring Implementation of the European Union Water Frame- program was established in 1988 to demonstrate the work Directive, eelgrass should be Included as an indi- effects of the Action Plan (for latest adjustments, see cator species. In future years, the coverage, depth Environmental Protection Agency""!. Large construction range and biodiversity of eelgrass beds may potentially works typically have associated monitoring programs, as be used for ecological classification of Baltic coastal was the case for the fixed link across Oresund. waters. Guidelines for monitoring eelgrass and other

As in Denmark, a series of action plans aiming to key macrophytes are included in the HELCOfvl reduce nutrient discharge have been agreed In Sweden COfvlBINE program""'. since the late 1980s, but not fulfilled. The latest action However, classification of Baltic Sea seagrass plan against coastal nutrient pollution is part of meadows as threatened Is only a first step obligating Swedish national environmental goals (Governmental regular quantitative estimates of the distribution

Proposition 20001, and specifically says that total patterns, dynamics and diversity of seagrass meadows. nitrogen discharge with anthropogenic origin from land Consequently, these parameters should be obtained should be reduced by 30 percent from 1995 not later and evaluated within standardized, national monitoring than 2010, whereas phosphorous should decrease programs. Presently, only a fraction of the Baltic Sea continuously from 1995 to 2010 with no specific aim. seagrass resources undergo regular monitoring. In

However, not only nutrient pollution but also future, such measures are crucial In order to overfishing might be part of the decreasing extension of understand and sustain these important ecosystems. seagrass through a possible, but still unverified, top- down control mechanism"^'. In the Baltic, as well as in ACKNOWLEDGMENTS the Kattegat and Skagerrak. most fish stocks are Tlie authors would like to thank the following persons for data, comments overfished to levels below biological safe limits. This is or logistical support during the preparation of the manuscript: Penina a much-debated topic, but has so far not been the Blanket!, Hartvig Christie, Jan Ekebom, Stem Fredriksen, Jakob subject of serious action plans. GjBsaeter, Fnda Hellblom, Agnar Ingolfsson, Hans Kautsky, Jonne Kotta,

Finland Is not committed to monitor seagrass Hordur Knstinsson, Jouni Lemikki, Mikael von Numers, Sergej Olenin, meadows. However, Finland follows political agree- Panu Oulasvirta, Lars-Eric Persson, Eeva-Liisa Poutanen, Thorsten ments, which are carried out by national (e.g. Water Reusch, Aadne Sollie, Stefan Tobiasson and Jan Marcin Weslawski,

Protection Targets for 2005, Renewed Nature Susanne P Baden gained financial support from WWF (World Wildlife

Conservation Act [1996], Renewed Water Act and EIA Fund) and the County of Vastra Gbtaland, and Dorte Krause-Jensen from

[Environment Impact Assessment) procedures) and the European Union l#EVK3-CT-2001-00065 "CHARM" and EVK3-CT- International [Habitat Directive and Natura 2000) 2000-OOOW "M&MS1. environmental programs. Thus, seagrasses in Finland are only Indirectly protected through limitations on AUTHORS nutrient discharges. A new governmental program Cfiristoffer Bostrbm, Abo AkademI University, Department of Biology, initiated In June 2001 alms at reducing nutrient Environmental and , Akademigatan 1, FIN-20500 Abo, discharges to the Baltic Sea and protecting and Finland. TeL +358 10)2 21 5i052, 4631045. Fax: +358 1012 21 53428. E-mail: monitoring marine coastal biodiversity. christofferbostromOabo.fi

At the International level, seagrasses are listed In the Rio Declaration (1992/93:131 as diverse habitats in Susanne P Baden, Gbteborg University, Department of Marine Ecology, need of protection and monitoring (Chapter 17 part D Kristineberg Marine Research Station, S-45034 Fiskebackskll, Sv^eden.

17.86 d). Further, the European Water Framework

Directive, the Habitat Directive, the Helsinki Convention Dorte Krause-Jensen, National Environmental Research Institute,

(HELCOfvll, the Oslo-Paris Convention (OSPARI and the Department of Marine Ecology, Vejlsovej 25, 8600 Silkeborg, Denmark. 61 .

36 WORLD ATLAS OF SEAGRASSES

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Hemminga Mk. Duarte CM 120001. Seagrass Ecology. Cambridge in a brackish water Zostera manna community indicate effects of

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53 Tobiasson S. Personal communication. clone in the Baltic. Marine Ecology Progress Series 183: 301-304.

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XXXIX pp 1-8. [Zostera manna] along a nutrient gradient in a Danish estuary. Marine

55 Lund 5 [19411. Tangforekomsterne i de danske farvande og fto/ogy 87: 211-218.

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in Danish coastal waters, 76 Greve T, Borum J, Pedersen [in press, 20031. Meristematic oxygen

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Long-term changes in eelgrass [Zostera manna] landscapes: Influence 77 Holmer M, Bondgaard EJ [2001]. Photosynthetic and growth response of

of physical setting on spatial distribution. eelgrass to low oxygen and high sulfide concentrations during hypoxic

58 Olesen B [19931. Population Dynamics of Eelgrass. PhD thesis, events AguahcSotany 70: 29-38.

Department of Plant Ecology, University of Aarhus, 78 Danish Ministry of the Environment and Energy, Danish Ministry of

59 Kaas H, Mohlenberg F, Josefson A. Rasmussen B, Krause-Jensen D, Transport, Swedish Control and Steering Group for the Oresund Fixed

Jensen HS, Svendsen LM, Windolf J. Middelboe AL, Sand-Jensen K, Link [20011. Final Report on the Environment and the Oresund Fixed

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FR179.pdf [accessed July 20021. Nord)yllands Amt,

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62 Messner U, von Oertzen JA [19911. Long-term changes in the vertical 4mi)io 29: 338-343.

distribution of macrophytobenthic communities in the Greifswalder 84 Environmental Protection Agency [20001. NOVA-2003

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Possibilities ol Restoration. IDS, Warszawa. pp 109-122 [in Polish with nursery habitats: An experimental assessment. Limnology and

English abstractl. Oceanograp/iy 45: 1041-1057.

65 Kruk-Dowgiallo L [19961. The role of filamentous brown algae in the 86 Laane A, Pitkanen H, Arheimer B. Behrendt H, Jarosinski W, Lucane S,

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Oceanological Studies 1-2: 125-135. Evaluation of the Implementation ol the 1988 Ministerial Declaration

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the Puck Bay and biotechnical approaches to its reclamation. In: Finnish Environment Institute, Helsinki.

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Baltic Marine Biologists Symposium. Olsen & Olsen, Fredensborg. pp Animal Communities in the Baltic Sea. Annex for HELCOM COMBINE

43-46. programme. 12 pp.

67 Ciszewski P, Ciszewska L, Kruk-Dowgiallo L, Osowiecki A, Rybicka D, 88 Institute of Marine Research, Flodevigen Marine Research Station.

Wiktor J, Wolska-Pys M, Zmudzinsky L, Trokowicz. D [1 9921. Trends of Unpublished data. 38 WORLD ATLAS OF SEAGRASSES

2 The seagrasses of WESTERN EUROPE

C. Hily M.M. van Katwijk

C. den Hartog

Western Europe is considered here as the coasts weakening of the plants under continuous unfavorable of the North Sea. the Channel and as environmental conditions, resulted in the 1930s in the

well as the Atlantic coasts of the British Isles, loss of almost 90 percent of the Zostera marina France, Spam and . Two seagrass species are populations of western Europe" '''. After this period,

found in coastal and estuarine areas: Zostera marina many beds progressively recovered but the area

and Zostera noltil. A third species, Cymodocea nodosa, covered remained low in most areas compared with

occurs less abundantly in the southern part of the area previous distribution. Zostera marina lives mainly in the (Portugal). The widgeon grasses, Ruppia maritima and infralittoral lor sublittorall zone but can develop

Ruppia cirrhosa. sometinnes considered to be occasionally in the lower and middle part of the

seagrasses, occur in brackish water sites'", such as mediolittoral lor eulittoral) zone. There the species low-salinity ponds and mesohaline to polyhaline develops a morphological variety with narrow and short

coastal lagoons; occurrence under marine conditions is leaves previously considered as a separate species,

very rare in western Europe and generally ephemeral. named , and which in many areas

The seagrasses are found on soft sediments to a behaves as an annual. It is noteworthy that in the

maximum depth of about 10 m. They occupy a large United Kingdom a specific distinction between Zostera

variety of marine and estuarine habitats. They often angustifolia and Zostera marina is still made'". Zostera

grow in dense beds and extensive meadows creating a noltii lives higher on the shore and occurs in the middle productive and diverse habitat used as shelter, nursery, and upper parts of the mediolittoral belt. The species

spawning or food area by a large variety of animal can also live under permanent subtidal conditions in species. Among these, several are of commercial small brackish streams and coastal lagoons with interest or cultural value. Therefore, seagrass beds are euhalme conditions.

recognized as an important reservoir of coastal In the United Kingdom. Zostera marina is the

biodiversity; they shelter in the same habitat more common species; it is widely, but patchily.

endotaunal and epifaunal species in the sediment, and distributed around the coasts of England. Scotland and creeping and walking species on the leaves, as well as Wales; the mam concentrations occur along the west

swimming species''^'. Seagrasses are consequently of coast of Scotland including the Hebrides and in considerable economic and conservation importance. southwest England including Devon and Cornwall, as

The dense root network of the seagrasses is able to well as the Scilly Isles and Channel Islands. The

stabilize the underlying sediment and to increase the intertidal form of Zostera marina is also widely sedimentation fluxes by reducing the hydrodynamic distributed, but less abundant; sites with major

. Their essential ecological role in terms of concentrations occur in the Exe Estuary, in Hampshire,

primary production at the scale of the coastal the Thames Estuary, and the Moray and Cromarty

ecosystem is mainly recognized in the areas where in Scotland. Zostera noltii has a predominantly

hard bottom surfaces with macroalgae cover are eastern distribution in the United Kingdom, more or

scarce. The importance of the beds was higher at the less coinciding with the distribution of the intertidal beginning of the 20th century, before the "wasting Zostera marina form"".

disease" struck. The proliferation of the pathogenic In Ireland. Whelan'"' carried out an extensive sur-

slime mold [Labyrlnthuta zosterae] in the leaves of vey of Zostera spp.; Zostera marina is frequently found

Zostera marina, considered to be the consequence of along the coasts under subtidal conditions IVentry Bay, Regional map: Europe

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THE BEAUTY OF SEAGRASSES

Thalassia testudmum meadow in Florida. USA

Spotted eagle ray teeding on benthic invertebrates in a bed of Tbatassia C.ovvrifisri and anemone in Enhalus acoroides and Tbatassia

testudinum and Syringodium Miforme, Turks and Caicos Islands, Caribbean. /)empnc/i// meadow in Kavieng, Papua New Guinea. Western Europe 39

—WT5 10* W 5»W 100 200 300 KilometefS 60° N I 60 120 180 240 300 Kilomelers '

^ J TLANTIC OCEAN

./• Glenan Isles * 4 ? -• Croinarl}' hirth "" Hebrides "'/ t i^ GulfofMorbihan Moriiv Fitih Loire Esliiaiy

4» Mareiuif.s-Oli'ron Basin --.

liiiifikohiiij' h'niixl Bavn/Bisc^n ^^ ^.^, 0° NORTH

SI:. I J .ircachon Ba\iii • 1 'i^v Ba\ —^ ' *' -- \ FiriH , . , . FRANCE Wudden

-^ Ueyn Peninsula

^ NETHERLANDS *> 4 ^ Samau Tliame-s • Gravelingen Ventty Bay ^ PORTUGAL /'&e Exilian- GERMANY •' BELGIUM ,• ^ / -'' SoUiii 50° N Scilty Isles, A* ^* IsleolWighl SPAIN PIvmoiilh

ilcdcBoiz-.^ Channel Is. „ „ . ^„...^^ ,. ,. ^^---^ Cotentin Peninsula FRANCE

^ Moni Si MitliclBcn Rla Formosa .. liuyufBrcsl — \ ics Bay Brehul Aa-hipcbgo CiliJnan Isles— • = Gulfof Morbihan .->

Western Europe InorthI .- c (iibraltar • ^ \f E p 1 T E R ft ! X t A .\ SEA

Galway sites, West Cork sitesl. Wasting disease Map 2.2 symptoms were observed in this country in ttie 1930s'". Western Europe IsouthI

The sandy, surf-exposed North Sea coasts of

Denmark, Germany, the Netherlands, Betgium and In Spam and Portugal, seagrass beds are

France are devoid of seagrass. Seagrasses are localized in drowned river mouths (nasi and protected restricted to the Wadden Sea area, which is protected bays (e.g. Vigo Bayl, with a zoned occurrence of from the full hydrodynamic forces of the ocean by the the two species of Zostera. Zostera noltii occurs on Frisian Islands. Along the Danish west coast, Zostera the large muddy mediolittoral flats and Zostera marina occurs in the enclosed Ringkobing Fjord. In the marina (accompanied sometimes by Cymodocea southern part of the Netherlands some intertidal popu- nodosa (e.g. Formosall in the upper part of the lations of the two Zostera species occur in the infralittoral. Ivlany of these beds are concentrated in estuarine branches of the mouths of the rivers the numerous Galician rias in northwestern Spain"". and Meuse. Some of these branches were diked in the In Europe, Zostera marina reaches the southern limit second part of the 20th century, but still contain some of its Atlantic distribution in southern Spain near submerged beds of Zostera marina (Lake Grevelingen, Lake Veerel.

In France, the two Zostera seagrass species are BIOGEOGRAPHY widely distributed. The brackish water species Ruppia Zostera marina occurs under a large range of maritima and Ruppia cirrhosa are uncommon and environmental conditions which can be identified as the mostly encountered in brackish ponds along the following three main biotopes; Channel coast, and the Guerande north of the Loire Sheltered habitats in enclosed and semi-

Estuary; their distribution is insufficiently known, (^/lany enclosed bays, estuaries and rias. with turbid small Zostera marina beds occur along the Channel low-salinity waters and muddy sediments. coasts from the west of Normandy to the west of Eelgrass beds are limited to a narrow depth range Brittany, mainly on the sandy bottom under both (<2 ml and because of the high turbidity do not intertidal and subtidal marine conditions""'. From the extend much below mean sea level. These beds west of Brittany to the south of the , the often appear as long narrow (<30 m wide) ribbons sites are either subtidal around islands IMolene and along the small subtidal channels which groove

Glenan ! or in very sheltered bays (Bay of the muddy intertidal flats (many North Sea sites,

Brest, Gulf of Morbihan, Arcachon Basinl in which they Galicia, Arcachon Basinl. In some sites (United can occupy large areas. Kingdom, Brittanyl the intertidal Zostera marina

'<: 40 WORLD ATLAS OF SEAGRASSES

form ["Zostera angustifolia"] can extend across biofilm and epiphytes, calculated by adding the surface

targe muddy areas in the medlolittoral belt, area of all the leaves of the shoots, can reach 6 to 8 m'

mainly on poorly drained sediments witti a thin in 1 m' of sediment (leaf area index). Whelan and water layer remaining at the sediment surface Cullinane"" identified 60 algal species in Ventry Bay during the low-tide period. (Ireland) and Connan and Hily"" found 82 epiphytic o Semi-open habitats under marine conditions algal species in Brittany beds including 60 species in

(salinity of 32-36 psul. These beds occur on sandy only one bed in the Bay of Brest. Some of these species

and locally even on coarse sediments from a are found only on Zostera leaves, or have their most depth of +2 m mean sea level to -3 m. Their luxuriant development on these, such as the small spatial extension depends on the rocky platforms, Phaeophytes Ascocyclus magnusii, Myriotrictiia small islands and hard substrate structures clavaeformis, Cladosiphon zosterae and Punctaria which protect the beds from the most extreme tenuissima. and the Rhodophytes Fosllella lejoUsii, hydrodynamic forces (strong currents, and Erythrotrichia bertholdii, Eryttirotrichia boryana and

waves). This type is common along the western Rhodophysema georgii. This epiphytic community,

coasts of the Channel. described as Fosliello-Myriotricfiietum clavaeformis,

Open habitats under fully marine and subtidat occurs only along the oceanic coasts and is very conditions (-2 to -10 m mean sea level! mainly sensitive to pollution.

around islands in very clear waters. Swell is In western Europe, many commercial fish and probably the main factor limiting the extension of shellfish species use eelgrass meadows as a habitat.

these beds to the intertidal zone. Zostera marina Some fish predators occupy the beds during tidal and

can occasionally be observed in artificial lagoons, nocturnal migrations (Labridae, Morone labrax and brackish pools and abandoned salt production flatfish). Others use the beds as spawning sites and areas on the French Atlantic coast"^' with a nursery areas \Muiius surmuletus]. The juveniles of the

morphology close to its intertidal morph, crab Maia squinado. an important commercial species

in France, hibernate in the sediments of the subtidal

Zostera noltil is very often found in estuarine and beds"". The beds are actively exploited by handnet sheltered environments as described above but fishermen for the shrimp Leander serratus. Many occupies higher levels on the shore. The species mainly commercial bivalves such the clams Venerupis

occurs in muddy and sandy sediments and can form pultastra, verrucosa, razor shells, Lutraria

extensive beds on tidal flat areas (Wadden Sea, United lutraria, and pectinids, Chlamys opercularis and Kingdom, Ireland, Gulf of Morbihan and Arcachon Pecten maximus, are especially abundant in the

Basin). The species is never found below the low-tide Zostera marina beds and are heavily exploited for mark. recreational fishing. Some rare and endangered species like the sea

PRODUCTIVITY, BIOMASS AND ROLE IN NUTRIENT horse {Hippocampus sp.) still occur in Zostera marina

CYCLES beds in the area. A few invertebrates directly consume

The primary production of Zostera marina meadows is the eelgrass leaves, e.g. the Sphaerechinus

the highest of the coastal sedimentary environments of granulans and the sea rabbit Aplysia punctata. Brent the region. The associated organisms supported by geese [Branta bernicla] used to be strongly dependent eelgrass production are numerous and diverse. The on the eelgrass meadows [Zostera noltii and Zostera beds are used as refuge and nursery areas by many marina] which are generally found in their main species, including commercial fish and invertebrates. migration sites. At present they have found alternative

At this latitude, growth of the perennial morph is food sources following the loss of eelgrass. Other birds

continuous throughout the year, although limited in such as teal, widgeon, pintail, mallard, shoveler,

winter, so there is a permanent flux of seagrass tissues pochard, mute swan and coot are also consumers of

inducing a detritus-based food chain. The detritus often eelgrass. becomes accumulated by waves and tidal currents outside the beds which thus spatially extend their HISTORICAL PERSPECTIVES

functional role in the marine ecosystem"'. It has been Before the outbreak of the wasting disease in the 1930s,

calculated that 1 g (dry weight) of seagrass detritus eelgrass beds were very common along the European supports on average 9 mg of bacteria and protists'". coasts. The beds were locally harvested for different The living leaves are used as a substrate by diatoms, uses (soil improvement (Galicia, Spain), embankment or bacteria and heterotrophic protists and many macro- dikes around fields on small islands (Brittany, France), epiphytes (algae and invertebrates). sea walls (the Netherlands), filling of mattresses and The total surface area available for the superficial cushions (Normandy, France, the Netherlands),

^ Western Europe 41

packaging, roofing and insulation material); therefore disease. From the 1960s onwards the eulittoral beds of eelgrass was historically of economic importance. As an Zostera marina and Zostera no/t» declined, probably as example, about 1 50 km^ were covered by eelgrass in the a consequence of increased turbidity"". In one site the western Wadden Sea"^'. Despite this abundance, already increased turbidity was found to be more related to by the 18th century, f^^artinet"" was urging development increased sediment particles, dredging and filling of a method to multiply eelgrass. because "one cannot activities than to increased phytoplankton. have too much of it""". Though little documentation is available, it seems that Zostera marina was more AN ESTIMATE OF HISTORICAL LOSSES abundant than Zostera noltii. Most of the subtidal Without doubt, the losses of areas occupied by eelgrass

Zostera marina beds did not recover from the wasting have been very great since the beginning of the 20th

Case Study 2.1 Sea. Water clarity of the Dutch Wadden Sea has THE WADDEN SEA improved and shellfisheries have been locally

prohibited. Experiments in the field, in outdoor

The Wadden Sea is one of the world's largest mesocosms and in the laboratory, as well as international marine wetland reserves. Before the literature, long-term environmental data and global

1930s it contained large beds of subtidal and low- information system (GIS] studies, all provided intertidal Zostera marina, whereas many mid- knowledge of suitable donor populations, habitat

intertidal flats were covered with a mixed bed of requirements and potential habitats'"' ™'"'. In 2002,

Zostera marina and Zostera noltii. After the wasting transplanting began in the western Wadden Sea.

disease in the 1930s, seagrasses survived only in the Risks will be spread in space and time, the

mid-intertidal zone la narrow zone around m mean transplants will be protected in the field during the

sea level]. Here, new losses occurred from the 1970s first years Ito prevent seed-bearing shoots drifting to

onwards. Increased turbidity, increased shell- open sea] and protective mussel ridges will be fisheries, increased construction activities and in- constructed to provide refugia for the transplants. creased nutrient loads are the mam factors that have

caused the losses and lack of recovery, although the causes of the wasting disease losses during the

1930s are still open to dispute™'". Currently, Dutch seagrass beds cover 2 km^ German seagrass beds 170 km^ and Danish

seagrass beds some 30 km^ In the Netherlands, an intensive monitoring program has revealed large

fluctuations in cover of Zostera manna particularly:

for example a sixfold increase in area was observed within two years Ifollowed by some decrease], whereas at another area an 80 percent decrease was obsei^ed between two different years Ifollowed by

some increase]. The Zostera noltii bed cover fluctuates less than twofold, which may be ascribed to some habitat characteristics, including firm clay banks, and the plants' perennial reproductive

strategy. The Zostera marina beds in the Wadden

Sea are mainly Ibut not totally] annual. These

fluctuations in cover make the populations vulnerable to local and temporal disturbances,

caused by human actions or by ice scour or gales, particularly when the area becomes small, and the

habitat offers no local refugia.

Since 1987, the University of Nijmegen,

assigned by and in cooperation with the Dutch

Government, has investigated the possibilities for

restoration of Zostera marina in the western Wadden Transplanted Zostera manna in the Wadden Sea, Nettierlands. A2 WORLD ATLAS OF SEAGRASSES

century in western Europe. After the wasting disease in seagrass before this human intervention, declined to the 1930s which destroyed most of the Zostera marina almost complete disappearance; in the early 1990s a beds, the recovery was very slow and at many sites small, completely submerged stand of a few square

eelgrass did not recover at all. From the 1 50 km' in the meters was found in very shallow water The extension western Wadden Sea estimated to be covered by of the Zostera manna beds soon came to a halt. A

seagrass In 1919 by van Goor"'"', the area estimate In large-scale die-off started around 1986-87, and has so

'^'. 1971 was reduced to 5 km' only In Intertidal areas"", far not been explained in a convincing way'" and the beds were estimated to cover approximately Most of the recent observations underline,

2 km' In ]')9A™, mainly consisting of Zostera noltiF". however, the gradual regression of the eelgrass bed

Glesen'"' considered that in 1990 Zostera marina had areas under anthropogenic influence. Human impact

declined to the point of virtual disappearance in the may be exercised directly by dredging, filling and mar-

Dutch Wadden Sea; at present only two locations of this ina development, aquaculture of mollusks lOstreidae,

species are still known in the area. Mytilidae, Veneridael and fish farms, anchoring and

In a few cases, anthropogenic shoreline other boat activities, and directly and indirectly by the modifications have facilitated the growth of eelgrass effects of eutrophication, such as increasing turbidity,

beds. In the second part of the 20th century several development of invasive macroalgae and floating blankets of macroalgae which may suffocate the seagrasses, and development of high biomass of

epiphytic microalgae and macroalgae on the leaves. In

the geographic area considered, the intensity of these

perturbations varies from one region to the other Along the Channel coasts the natural harbors are used as semi-permanent anchoring sites for pleasure boats as here the optimal conditions for this activity,

including tidal level considerations, protection from swell and currents, and distance from the shore are met. Unfortunately, these are exactly the sites where

Zostera marina has its ecological optimum. This

activity IS an important cause of the erosion of eelgrass

beds and it Is increasing very rapidly everywhere. In the

same way, recreational fishing Is increasing; the

digging of mollusks during low tide at spring tides by very destructive tools induces a rapid regression of the

intertidal parts of Zostera marina beds. Numerous eelgrass sites of Zostera noltii and Zostera marina are progressively disappearing with the rapid extension of

aquaculture. In France and Spain, on intertidal sites. In Cornwall and Devon (southern England) many losses were pointed out by Glesen'^' by comparing the results

Aerial pliotograph showing the impact of sh-,.' sr^r -;. ;n an given by Covey and Hocking''", and Holme and Turk''*';

intertidal Zostera noltii bed. no explanations were found for these losses. The less- threatened beds are probably the deeper subtldal

large constructions along the coast of the Netherlands Zostera marina meadows under semi-exposed modified the sites colonized by eelgrass. The conditions particularly around small islands, but the

construction of a dam In 196^, 25 km upstream of the continuously increasing turbidity of the coastal waters

Grevellngen Estuary, isolated the ecosystem from the in western Europe, generally recognized but not really

freshwater Influence; at that period the eelgrass beds quantified, is probably a factor In the variations of the

covered about 12 km' in the Intertidal belt. Then, in lower limits observed in many beds. As an example, llrelandl 1 971 , a second dam at the mouth of the estuary Isolated the lower limit of Zostera marina in Ventry Bay the system from the sea's Influence. The Grevelingen was 13 m in 1977-78, 10 m In 1980 and continued to fall Estuary was transformed Into a stagnant salt water after 1980'". lake. The new conditions favored the extension of the The loss of eelgrass has not been quantified for Zostera marina beds, which became permanently the whole region, but probably more than 50 percent of

submerged, and occupied about 3A km^ In the period the beds are subject to one or other of the types of ^V 1971-85'"'. Zostera noltii, which was the most common perturbations mentioned, and are threatened by total

^ Western Europe 43

or partial destruction over the next ten years. A review known, but many beds are recorded from the numerous of the abundant literature concerning eelgrass in rias of the Galicia region [Zostera nolti, covers western Europe suggests that the general trend of approximately 20 km' between the French and recovery after the almost complete disappearance of Portuguese coasts""). In Portugal, the Ria Formosa is the sublittoral beds in the 1930s is largely being recorded as a site for intertidal Zostera noltii beds and reversed by the diverse, and generally adverse, local subtidal beds of Zostera marina and Cymodocea and regional anthropogenic impacts. nodosa.

It IS at present not possible to measure the

AN ESTItvlATE OF PRESENT COVERAGE potential seagrass habitat in the whole region.

In France, along the Channel and Atlantic coasts, most However, it can be estimated that it would be more than of the eelgrass sites are known. Along the western three times the actual coverage both for Zostera coast of the Cotentin Peninsula, beds of Zosters marina marina and Zostera noltii. An estimate for Brittany is occur near Granville, and the most eastern beds of planned in 2003 with a long-term survey of the coastal

Zostera noltii are in Baie des Veys near Isigny on the benthic communities (REBENT network survey) eastern side of the peninsula'"'. Eelgrass beds in including Zostera beds. In the United Kingdom the

Brittany were located and mapped in 1999 by Hily e( Habitat Action Plan for seagrass beds developed by the a/.'"", although the exact area of each bed has not been UK Biodiversity Steering Group may result in quite an determined. This study identified more than 70 sites accurate estimate of the potential habitat in this area. from the Mont St Michel Bay in the north to the Loire

Estuary in the south of Brittany. Most of them are small PRESENT THREATS beds between 1 and 5 ha. but there are at least ten Direct destruction of beds large beds covering 10 to more than 100 ha (including As a result of the rapid development of pleasure fishing the Gulf of Morbihan, Glenan Archipelago. lie de Batz, and sailing over the last 20 years, filling and dredging

Bay of Brest, Brehat Archipelago. Abers Estuaries and for extension or creation of harbors have destroyed

Etel Rial. To the south, the Marennes-Oleron Basin is a many eelgrass beds. As a consequence of economic large site of Zostera noltii. Further to the south the and environmental arguments such developments are

Arcachon Basin is the largest site of Zostera noltii (70 becoming less harmful nowadays, but the damage has km' in 19841 in Europe, and also a large site of Zostera been done. manna (4 km' in 1984]'"'. Oyster and mussel aquaculture on littoral

In the United Kingdom, most of the beds are sediments has been the cause of the destruction of mapped and consist of about 140 sites of Zostera many eelgrass beds because the optimal conditions for marina (including the intertidal sites! and about 70 the culture of these animals correspond with the sites of Zostera noltii"'. Some of them extend over a optimal conditions for the beds. This activity is still considerable area, such as the Zostera marina bed in expanding, and will probably be one of the main threats the Cromarty , Scotland, which covers 12 km"'" to the beds in the future. and is considered the largest bed in the United Anchoring and mooring outside harbors is

Kingdom. In the cross-border sites of Scotland and damaging. Anchoring causes the formation of deep

England, the Solway Firth and the northern holes which in their turn may become points of impact

Northumberland coasts have coverage respectively of for the eroding forces, while the chains dragging across 2 and 9 km""™. Along the coast of England, the the bottom destroy the surrounding biocenoses seagrass coverage of some large sites has been including the seagrass communities. documented: Essex estuaries 18.44 km'). North Thames Hand fishing for clams using rakes, forks and

Estuary (3.25 km'l, Solent and Isle of Wight (4.40 km'l, hoes to catch the endofaunal bivalves at low tide, as Plymouth Sound and estuaries (6.50 km'). Some well as within the seagrass beds, results in whole smaller beds occur in Devon and Cornwall. In Wales, plants with their rhizomes being pulled out of the the main sites are in the Lleyn Peninsula and the sediment. This causes considerable damage to the

Sarnau, while in Northern Ireland the beds in the seagrass beds, because it is generally followed by

Strangford Lough cover 6.30 km"". Zostera marina erosion. Collecting clams in this way is becoming very beds are also common on the semi-sheltered popular, so this type of perturbation is increasing in sediments of the Channel Islands. western Europe'^". The same kind of perturbation is

Along the southeastern coasts of the North Sea, caused in the eulittoral seagrass beds by digging for seagrass beds are restricted to the sheltered Wadden polychaetes such as Arenicola and Nereis to be used Sea and southwest Netherlands and cover a total of as bait. 200 km'. Professional fishermen on boats dredge on the

In Spain, the actual seagrass coverage is not limits of the beds to catch bivalves. The natural 4A WORLD ATLAS OF SEAGRASSES

acclimation of the Japanese clam Venerupis reduce light and cover the leaves of seagrass during

phiUppinarum In the south of the area (from south resedimentation. Dredging for harbor and channel

Brittany to Spain] increases the direct impact of this maintenance and releasing the dredged sediments on

activity on the seagrass beds because this species the seafloor also increases turbidity and lowered light

develops dense populations In and around the eelgrass levels.

beds of the sheltered bays and estuaries"". In the Spatial competition with invasive species may Netherlands, much damage has been done to the few also limit the extension of seagrass beds In western

still existing eelgrass beds by professional cockle Europe. The brown algae Sargassum muticum Is able fisheries with their modern, effective, but environ- to develop in the eelgrass beds where the sediment mentally unfriendly equipment. floor is coarse or includes gravel, stones and/or shells.

In these beds Sargassum gradually takes over and Indirect destruction of beds prevents the rejuvenation of eelgrass"^'.

Eutrophication is the main cause of indirect destruction Most of these threats concern the eelgrass

of seagrass beds. The increase of organic matter and Zostera marina. The intertldal species Zostera noltii nutrients from terrestrial effluents favors phyto- has been assumed to be threatened by a combination of

. causing blooms which in their turn decrease various factors including turbidity, eutrophication and

light availability. Moreover, plankton production associated epiphyte cover, the decrease of mud snail

increases not only In terms of Instantaneous blomass populations [Hydrobia ulvae] which graze on the

but the period of production also becomes longer and epiphytes, and also as a result of bloturbation by the

longer, and can be observed all year in some areas with lugworm Arenicola marina. These processes have been numerous successive small blooms'"'. As a cons- well studied in the Dutch Wadden Sea by Phillppart'™. equence of these plankton blooms, the water trans- Finally, a very important potential threat Is parency decreases, limiting the light available for the shipping. The Channel and the southern North Sea are

growth of Zostera. among the worlds busiest shipping routes and the Apart from this shading effect by plankton, a chance that accidents will occur cannot be excluded

further reduction of light is brought about by increased ladverse weather conditions; human error). Notorious

epiphyte cover on Zostera leaves In which both diatoms disasters were those with the tankers Torrey Canyon and macroalgae participate. The specific community of and Amoco Cadiz in the western Channel and recently

small epiphytes mentioned above is. however, the first Eril

element to disappear from the seagrass bed in the case the whole coastal ecosystem has been disastrous.

of eutrophication. Eutrophication also Increases the

production of green macroalgae [Enteromorpha, Ulval; POLICY RESPONSES

particularly in semi-enclosed, sheltered bays the green The European Union lEUI elaborated a Habitats algae can form thick blankets which float around and Directive for both terrestrial and marine habitats which can be deposited on the Zostera beds of the sandy and identifies the mam natural habitats and their cultural

muddy Intertldal flats during periods of very calm value for further consideration In terms of protection weather. Under such conditions the seagrass beds and conservation. In this context eelgrass beds are become smothered and suffocated, leading to complete Identified as particular ecological units of several

die-off within a very short tlme'^". When these blankets marine habitats: sandy shore, mud flats and coastal

are deposited on the bare surface of the intertldal flats, subtidal sandy sediments. These initiatives have led to the spatial competition favors the green algae which eelgrass habitats being specifically targeted for

prevent the extension of the seagrass beds, and reduce conservation and restoration'^". But although they are

the growth of shoots by shading and suffocation effects considered as biotopes of special Interest, they are not

in the areas where they border the seagrass beds. In considered as "endangered" and so not considered for these conditions the beds decrease progressively, and immediate and strong protection. In France Zostera

may completely disappear In a few years. marina Is listed In the Red Book of threatened species

The increase of turbidity is not only associated but is not In the list of protected species. Zostera noltii

with eutrophication. but can also result from an Is not considered. Additionally, very locally and in few

Increasing input of terrigenous particles by river localities, some Zostera beds are protected by

effluents as a consequence of large-scale changes in municipal authorities. In March 2002, Zostera marina agricultural practices; modern practices encourage the and Zostera noltii were both incorporated in the Dutch

leaching of soil In winter. Extraction of calcareous Red List of threatened plants.

sediments and calcareous macroalgae [Llthoptiytium In the United Kingdom, the eelgrass beds have

sp.l from sublittoral beds Induces high turbidity; the been considered for many years as targets for

high levels of sediment in suspension In the water conservation and a habitat action plan for seagrass

J Western Europe 45

Case Study 2.2 throughout the year induces fragmentation of

GLENAN ARCHIPELAGO the beds in five main sheltered subtidal sites; recreational fishing for clams induces

In the northern part of the Bay of Biscay, the Glenan fragmentation of the intertidal beds;

Isles are located 9 mites off the continental coast of extraction of calcareous sediments Imaerl south Brittany, France. The area is characterized by beds) 1.5 miles off the archipelago induces ten snnatl islands and numerous rocky heavy turbidity in the northern waters of the surrounding an enclosed, shallow l< 5m deep], archipelago which may limit the extension of sandy area well protected from the oceanic swell. the beds in depth la decrease of the deeper

Aerial photographs are available from the year 1932 limits of the laminarians close to the beds was and allowed estimates of the long-term develop- recently demonstrated""). ment of the areas covered by eetgrass""'.

This is an interesting experimental site be- This example underlines the complexity of the cause the continental influence (eutrophication and dynamics of the eelgrass beds which are under the associated consequences) Is minimized which Influence of factors working at various spatial and allows the obserA/ation of the natural dynamics of the temporal scales: here the positive climatic factors beds under climatic factors, but also because working at the global scale compensate for the human activities (anchoring, fishing] induce local negative impacts of the perturbations induced by perturbations in the eelgrass beds. So it is possible human activities at the local scale. to separate the role of each of the factors that This example also underlines the difficulties of control the dynamics. seagrass conservation: it is hard to explain to the

Based on the cover in 1932, it can be authorities and users alike that human activities considered that a surface of 10 l

Is also observed In many beds of the Brittany Impacts, would induce dramatic and rapid loss of coasts"". However this evolution Is moderated by the the beds, and consequently preventive action should negative impacts of numerous human activities'"': be planned. dredging for clams by professional fishing Fortunately, the management authorities at

boats prevents recolonizatlon in the opened this site are working with the scientific teams on a

central subtidal part of the area; sustainable development plan to preserve the Image

anchoring by numerous pleasure boats of high environmental quality in this tourist area.

Anchonng on a Zostera manna bed in Glenan Archipelago. 1

46 WORLD ATLAS OF SEAGRASSES

France they are called "sites Natura 2000". The regulations suggest that relevant authorities from the

various sites should work together within a

management group. In most countries, the presence of Zostera beds has been a criterion (but not the only one]

to retain a site as a SAC. When a bed is included in a

SAC, specific management is required for the bed. This

procedure is to be applied independently by each country, and has not yet been achieved. Some sites

derive their conservation status from a combination of

several different directives, and this can reinforce the conservation of Zostera beds. For example, some sites are also RAMSAR sites and/or sites of the EU Birds Directive, which reinforces the international recognition

of the sites importance and requires the government to

strongly protect the site. However, the sites indicated

according to these directives are far from covering all

the eelgrass beds in Europe. It therefore remains very

important to give global consideration to eelgrass

habitats on a wide scale and it remains necessary to

define specific conservation regulations at the level of the species or genus and/or the habitat.

ACKNOWLEDGMENTS

Zostera manna on a maerl bed in the Bay of Brest Dr R M Asmus kindly provided Zostera manna cover percentages for the

German Wadden Sea. Thanks to Ingrid Peuziat who provided data on the

beds was prepared by the UK Biodiversity Steering Glenan Archipelago.

Group. In a complementary way, the South West Regional Biodiversity Habitat Action Plan has also been AUTHORS

developed. These initiatives are integrated in the EU Christian Hily, Inslitut Universitaire Europeen de la Mer jUniversity of

Habitats Directive which requires the identification of viiestern Bnttanyl, Technopole Brest Iroise, 29280, Plouzane, France.

European marine sites in a network called "Natura Tel; +33 1012 98 49 86 40. Fax: +33 1012 98 49 86 45. E-mail:

2000"; sites which should be managed in order to chnstian.hilyrauniv-brest.fr maintain or restore the favorable conservation status of

their habitats and species. Each state of the EU has the Maneke M. van Kalwyk, Departnnent of Environmental Studies, University

statutory responsibility, via the conservation agencies, of Nijmegen, P.O. Box 9010, 6500GL Nijmegen, Netherlands.

for developing conservation objectives in each site,

defined as a statement of the nature conservation Cornelius den Hartog, Department of Aquatic Ecology and Environmental

aspirations for a site. In the United Kingdom these sites Biology, University of Nijmegen, PO. Box 9010, 6500GL Nijmegen,

are called SACs Ispecial areas of conservation!, in Netherlands.

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1*1 21-38. 20 Philippart CJM [1994]. Eutrophication as a Possible Cause of Enteromorpha radiata. Aquatic Botany : threat lo eelgrass Decline in the Seagrass Zoslera noltii of the Dutch Wadden Sea. 35 den Hartog C 11997]. Is Sargassum mulicuma 37-41, PhD thesis, University of Wageningen. Netherlands. 157 pp. beds' /tquaticSofany 58: Hawkswetl S. Juniper 21 Dykema KS, van Tienen G. van Beek JG 11989]. Habitats of the 36 Wynne DW, Avery M, Campbell L. Gubbay S. King M, P. Smart J, Steel C. Stones T. Taylor J. Netherlands, German and Danish Wadden Sea 1 :100,000. Research T. Newbery

Institute for Nature Ivlanagemenl, and Veth Foundation, Tydeman C, Wynde R 119951. Proposed targets for habitat

Leiden. conservation. In: Biodiversity Challenge. 2nd edn. RSPB, Sandy, 22 Nienhuis PH, de Bree BHH, Herman PMJ, AMB, Bedfordshire. 285 pp. Jong DJ. RM. de Jonge Verschuure JIvl, Wessel EGJ 11996]. Twenly-hve years of changes in 37 van Katwii|k MM, Hermuus DCR. de Asmus for restoration of the distribution and biomass of eelgrass, Zoslera manna, in VN 120001. Habitat suitability of the Wadden Sea 17-128. Grevelingen Lagoon, the Netherlands. Netherlands Journal ol Zoslera manna beds. Helgoland Manne Research 54: 1 Aquatic Ecology30:im-]]r 38 van Katwii|k MM. Schmitz GHW. Gasselmg AP, Van Avesaath PH salinity nutrient load and their interaction on 23 Herman PfvlJ, Hemminga MA, Nienhuis PH, Verschuure JM, Wessel 11999]. Effects of and Progress Series 190: 155-165. EGJ [1996]. Wax and wane of eelgrass Zoslera marina and water Zostera manna. Manne Ecology van Katwijk MM. den Hartog C 11990]. Eelgrass column silicon levels Manne Ecology Progress Series 1 44: 303-307. 39 Giesen WBJT,

in Dutch Wadden Sea. Aquatic Botany 24 Covey R, Hocking S [1987] Hellord River Survey. A report to the condition and turbidity the 37:71-85. Helford River Steering Group. 121 pp. Y, Long-term changes of 25 Holme NA. Turk SM [19361. Studies on the marine life of the 40 Glemarec M, Le Faou Cuq F [19961. Archipelago [South Brittany], Helford River: Fauna records up to 1910. Cornish Biological seagrass beds in the Glenan 20111: 217-227. Records No. 9. 26 pp. Oceano/og/ca/lc(a Castric A. Personal communication. 26 Le Gall J. Larsonneur C 119721. Sequences et environnements 41

^ 48 WORLD ATLAS OF SEAGRASSES

3 The seagrasses of THE WESTERN MEDITERRANEAN G. Procaccini M.C. Buia M.C. Gambi M. Perez

G. Pergent

C. Pergent-Martini

J. Romero

Studies on seagrasses in the communities of the Mediterranean coastal area'^'. ''' date bacl< to the beginning of the 19th century, Meadows are very dense with over 1000 shoots/m' when the most widespread and well-known although this varies from year to year'". The horizontal species, Posidonia oceanica, was described for the first and vertical growth of rhizomes, and the slow decay of time. Since then thousands of papers have detailed this material, causes Posidonia oceanica to form a different aspects of seagrass distribution, ecology, biogenic structure called "matte", that arises from the physiology, faunal and algal assemblages and, recently, bottom up to a few meters and can be thousands of years

genetics. Two international workshops in the early old'^'. Posidonia oceanica is a monoecious species, with 1980s were dedicated to the endemic Posidonia male and female flowers in the same inflorescence.

oceanica and led to joint research programs among Sexual reproduction is sporadic, especially in some

European countries to study the structure and areas. Posidonia oceanica has low genetic variability and

functioning of the Posidonia oceanica ecosystem. Less meadows represent genetically distinct populations, information exists on the other Mediterranean even at a scale of a few kilometers'". A clear genetic seagrass species, although some of them are quite distinction exists between northwestern, southwestern

common and widespread in the basin. A significant and eastern populations. Meadows are composed of a contribution to the synthesis of the work conducted on mosaic of large and ancient clones" ". Mediterranean seagrasses was offered by the Cymodocea nodosa most commonly occurs in

organization of the Fourth International Seagrass shallow water but exceptionally can reach a depth of

Biology Workshop held in Corsica in 2000'". 30-40 m. Shallow and deep stands are generally

discontinuous. Cymodocea nodosa is usually found on SPECIES DISTRIBUTION sandy substrate and sheltered sites'". In France, the

Six seagrass species are present in the Mediterranean most important beds are known in coastal lagoons.

Sea, forming an almost continuous belt all along the Shoot density reaches almost 2000 shoots/m"". It has coasts: Posidonia oceanica; Cymodocea nodosa, also classically been considered to be a in present along the North Atlantic African coasts and the succession leading to a Posidonia oceanica climax

Portugal; Zostera manna and Zostera noltii, both with system'''. However it also grows in areas previously

a wide temperate distribution; l-ialophila stipulacea. colonized by Posidonia oceanica and characterized by

probably a recent introduction from the Red Sea; and dead matte. Cymodocea nodosa is a dioecious species.

Ruppia spp., with a wide temperate distribution (Table Seeds remain for a long time in the sediment, attached

3.11. Extremely limited information is available on to the mother plant. The only existing analysis of

Ruppia in the Mediterranean and it will not be Mediterranean meadows showed high genetic diversity.

considered further In fact, plants 5 m apart within a meadow were Posidonia oceanica forms continuous meadows genetically distinct individuals""'.

from the surface to a maximum depth of some 45 m and Zostera marina is considered to be a relict

is common on different types of substrate, from rocks to species in the Mediterranean, where it forms perennial

sand, with the exception of estuaries where the input of meadows distributed from the intertidal to a few

freshwater and fine sediment is high. Posidonia oceanica meters deep. It can grow on sandy and muddy

beds have classically been considered one of the climax substrate and is also present in lagoons"", though it is E

The western Mediterranean 49

10" w eUgoon-^' '»-&•"'/ "/T-ri^K-v. .X ' Rousslllon ^ ^ Provence Alpes , 1 . CROATIA ; : A 1 V*-:- !\^-^~^ "f Marse.lle> ^ '"•Monaco Delia ^\ \ ' 1 Catrtorta • - UGVRIWSEA 7

Tuscany V. f-. -* ,' SPAIN • Numana Medes Is ^J\ *^ ''f \ .^ C'wsi forsicai / ITALY ,.^S?A 4 VaJenda AifiK-s Btn X f '-'*4^..- 1 • \/ Lailo , ^.

* Apote ADRIATIC Andakjda Ijjlcanclslands Sandinia/ r • Ischia 1 - • .^ < • * TVSRIIEMiy i.f-J*^ S £ 1 40" N M E D 1 T E R R A N E .1 .V i' E A Calabrta

• MOROCCO ^ V. • / lOfJIA ^** / -^^f ALGERIA TUNISIA XN_ ( 100 200 300 Kilometers i 0' ^S'Af 10- x; E

Map 3.1 The western Mediterranean

rare throughout the Mediterranean. Shoot density in Halophiila stipulacea was recently introduced to

Zostera marina beds is almost 1 000 shoots/m^"". the western and was reported for

Zostera marina is a monoecious plant. Studies on the the first time in 1988. In the eastern Mediterranean genetic diversity of this species have never been basin this species has been observed from the

performed in the Mediterranean. beginning of the 19th century and is believed to have

Zostera noltii grows from the intertidal to depths been transported from the Red Sea, through the Suez

of a few/ meters on sandy and muddy substrate"". It is Canal, an example of Lessepsian migration. In the

also present in enclosed and sheltered areas, where it Mediterranean it is distributed from the intertidal zone

can form mixed beds with Cymodocea nodosa, at to 25 m'"'. It can grow on sandy and muddy substrate,

densities up to almost 1 300 shoots/ml Zostera nottii is and is present in enclosed areas. Shoot density is

a monoecious species and no information is available extremely high, up to almost 19000 shoots/m' in

about the genetic variability of its populations. shallow water'". Halophiila stipulacea is a dioecious

Table 3.1

Examples of general features of Mediterranean seagrass meadows

Posidonia Posidonia Cymodocea Halopt\Ha Haloptiila Zostera Zosfera

oceanica oceanica nodosa stipulacea stipulacea noltii marina

shallow deep shallow deep

Density Ishcots/m'l 700 161 925-1 925 19728 13000 269-1 246 216-1093

Leaf area index (m^/m^l 6.16-29 1.1-2.6 0.2-3.5 5 5.9 0.2-0.4 1.7-6.7 - 13-79 45-775 Leaf biomass Ig dw/m^l 175-670 52-94 17-159 157.8 - - 31-62 21-161 Below biomass Ig dw/m'l 6 526 324 300-750 - - - - Epiphyte biomass (g dw/m^| 7-U7 3-21.3 3.4-12.5

- - - - 0.7-3.2 Animal biomass Ig dw/m^l 0.077-0.4 1.0-2.6

Number of algal species 36 50 35 30 8 25 - - - Number of animal species 38-60 22-84 83 53 - - Animal density |individuals/m^l 380-1 100 210-680 1486 2035 - - 70-949 109-2299 Leaf production Ig dw/m7yl 162-722 71.3-232 23.6-1 623

- - - Rhizome elongation Icm/yl 1.1-7.4 3.6-57.8 91-168 18-91

' - - 1-3 Leaf lifespan (months) 11 11 5 -

Source: Modified from Buia eta '". Values derived from key studies listed in Buiae(a/."'. 50 WORLD ATLAS OF SEAGRASSES

Case Study 3.1 part of the . Posidonia oceanica

ITALY covers about 17 km^ of the seafloor, and its

meadows, forming a continuous belt around the

LIGURIAN COAST island, were mapped in detail in 1779'"'. The

The Ligurian area is one of the best among the different exposure of the coasts of the island,

Italian coasts for information on the distribution coupled with different environmental conditions

and general status of seagrasses. in particular for and bottom type, give rise to meadows extremely

Posidonia oceanica. Almost 50 Posidonia oceanica diversified in terms of physiognomy (continuous main meadows have been recorded and and patchy beds], depth range (from down to

mapped™. Their extension ranges from a few to 38 m in depth), shoot density (from a mean of 700

several hundred hectares, covering in total about shoots/m' at 1 m to 80 shoots/m' at 30 m depth]

48 km'. In general all the prairies are in different and biodiversity of associated communities (more

states of degradation due to coastal modifications than 800 associated species], and with low

for harbor and town development. In addition intrinsic genetic variability, coupled with a degree

some Posidonia oceanica beds were impacted in of isolation between shallow and deep stands"".

the early 1990s by a crude oil spill following the A recent monitoring of beds around the

wrecking of the oil tanker Haven, considered to be island (in the year 2000) demonstrates a

one of the worst Mediterranean oil spills"". substantial stability of distribution and the

presence of other settlements not previously reported'"'. However, long-term studies carried

out since 1979 in beds off Lacco Ameno have

detected a reduction in shoot density, as a result of

anchoring, the impact of the local fishery and a

nearby wastewater outfall.

NORTH ADRIATIC COAST (VENICE LAGOON]

Zostera marina is present on the Italian coasts of

the north - it was first recorded here

in the Uth century. Posidonia oceanica has

experienced a strong decrease in this area, being

now limited to a few patches in the Gulf of Trieste'"'. The worst decline of Posidonia

oceanica has occurred in the Venice lagoon. In

1 990 Zostera manna covered an area of 36.5 km^ forming pure and continuous beds of 2M km^ and

beds mixed with Zostera noitii over the other 34 I^pj^2iz5,26i ^Qgfgf-g no/f/Vwas the most widespread species (42.5 km') and Cymodocea nodosa was also present (15.6 km'). Monitoring results four years later from the southern part of the lagoon'"' showed an increase of about 7.6

percent in the overall extent of seagrass beds, but with more Zostera marina (an increase of

13.5 percent], a decrease of 10.1 percent in

Cymodocea nodosa and a large decline in

Posidonia oceanica banquette on the Cava dell'lsola beach, Zostera noitii (24.7 percent). The monospecific

Ischia Island, Italy. and discontinuous beds have increased while mixed species beds have declined. A high survival TYRRHENIAN COAST (ISLAND OF ISCHIA] rate for Zostera marina. Cymodocea nodosa and

At a smaller spatial scale, the best-known Zostera noitii has been achieved in transplanting

Posidonia oceanica meadows are those experiments using sods and rhizomes at various

surrounding the Island of Ischia, in the northern sites in the lagoon'™-'". The western Mediterranean 51

species. Male flowers are frequent in the Serranus cabrilla], Labndae (e.g. Coris julis and

Mediterranean Sea but fennale flowers were only Crenilabrus maculatus] and (e.g. observed for the first tinne in 1998. in Sicily"^'. Studies scrofa and Scorpaena porous], and the sea on the genetic variability of two populations located urchin Paracentrotus lividus. Among the rare or along the Sicilian coasts showed that each shoot endangered associated species are the endemic sea represents a genetically distinct individual. Genetic star pancerii, the sea horse Hippocampus relatedness was higher among individuals collected at hippocampus and the bivalve Pinna nobilis: these the same depth"^'. species are protected, in both Italy and France, or are

included among species requiring a specific legislation ASSOCIATED SPECIES for protection"". Seagrass ecosystems of the western Mediterranean are extremely rich in a number of associated plant and EXTENT OF COVERAGE animal species. However, complete lists of associated Information on the distribution of seagrasses is species have been compiled only in a few cases, such scattered and therefore an estimate of the total area as the Posidonia oceanica and Cymodocea nodosa covered by seagrasses is difficult to mal

Campanuiana asymmetrica, Cordyiophora pusilla and occur in Liguria, Lazio, Sardinia, Veneto and Friuli

Laomedea anguiata'"'"". (Table 3.21. France has approximately 1 150 km' of Posidonia oceanica meadows are nursery Posidonia oceanica beds, but estimates for other grounds for the juveniles of many commercially species are not available. On the Mediterranean coasts important species of fishes and invertebrates, such as of Spam, some regions have mapped their seagrass several species of the family Sparidae (e.g. Diplodus meadows in great detail allowing an estimate of more sargus and Diplodus annularis]. Serranidae (e.g. than 1 000 km* to be made.

Case Study 3.2 the 1970 area. This is most likely due to the high FRANCE levels of suspended matter, ammonium and phosphate coming from the treatment plant. After MARSEILLE-CORTIOU REGION 1994, a natural recolonization of Posidonia

A long-term monitoring study of Posidonia oceanica was observed in certain areas, due to

oceanica beds in the Marseille-Cortiou region has increased water clarity recorded fluctuations over the 1883-1987 period,

and the impact of a sewage treatment plant. In the CORSICA

period 1 890 to 1 898, when a sewage outlet was first Corsican coasts experience low human impact

set up in Marseille, the seagrass bed had reached with many marine protected areas; almost

a depth of 30 m and occupied an area of about 71 percent of the Corsican coastline is still in its 6.32 km^ A number of authors noted loss of natural state. Posidonia oceanica beds occupy a Posidonia oceanica between 1900 and 1970 as the total surface area of 624 km"'" mainly along the

city of Marseille expanded™. At the end of the eastern side of the island, where the continental

1970s the bed covered a smaller area, with a loss shelf is very wide. Their distribution is limited on

of 5-6 percent per decade. the steep and indented west coast. Upper limits

When the wastewater treatment plant was are generally between 1 and 10 m depth, while

set up in 1987, the lower limit of the seagrass bed the lower limit at several sites on the east coast

was just 10 m and it included vast stretches of IS situated below 40 m. The lower limit rises to dead matte. Since then there have been further, a depth of 15-20 m near large cities such much greater, losses amounting to 40 percent of as Ajaccio. 52 WORLD ATLAS OF SEAGRASSES

The beds of Posidonia oceanica are among the PRODUCTION AND BIOMASS most important Mediterranean ecosystems, and their Both below-ground and above-ground biomass values

conservation is a high national and international of Posidonia oceanica exceed those of other seagrasses, striking priority le g. EU Habitats Directive 92/43/CEE, 21 May including the Australian Posidonia species"™. A 19921. Posidonia oceanica beds exert a multifunctional feature is the distinct partitioning of the biomass, mainly

role within coastal systems, comparable to that of other directed into the lignified rhizomes, which can account

seagrasses in temperate and tropical areas, offering for up to 90 percent of total biomass'"'*'and production substrate for settlement, food availability and shelter, where leaves account for more than 90 percent'"'. In an

as well as participating in l

Table 3.2

Distribution of seagrasses throughout the western Mediterranean (Italy, France and Spain]

Sites Po Cn Zm Zn Hs Area Comments

Ikm-'l

ITALY

Liguria* / / 48 On rocl

Tuscany* / / / - On rocky and sandy bottom, from to 40 m'" '.

Lazio / / / 200 Large extensions of dead "matte". Meadows in regression at north of the

Tevere River due to sedimentation from construction works. Illegal trawling

within the depth of 40 m'™'".

Campania' / / / / Beds with different typology, extension and morphological features, due to

the highly variable environmental conditions and sea bottom

topography'""'.

Calabna" / / / / - Beds with different typology, extension and morphological features, due to

the highly vanable environmental conditions and sea bottom topography

Apulia / / / Posidonia oceanica is frequent along the southern Adriatic and the Ionian

coasts. Meadows grow on old "matte" remains, in the Gulf of Taranto, while

they grow on sand or rocks along the Adriatic side of Apulia. Posidonia

oceanica is also present at the Tremiti Islands'""'.

- Central / Posidonia oceanica is absent from the Po to the northern Apulian

Adriatic coasts coasts. No information on other seagrasses except for Zostera manna

(Numana Harbor, south of Anconal.

Venetc and / / / / 96 Seagrasses are not abundant along the northern coasts of the Adnatic Sea,

Fnuli V.G. which is influenced by the freshwater inflow and fine sediment coming from

the Po River Posidonia oceanica is present only in a few patches in the Gulf

of Trieste and in the Venice lagoon, where Zostera manna is present in one

of the few spots of the Mediterranean Sea'"'"'*'.

Sicily* / / / / Posidonia oceanica is present all along the Sicilian coast. Dense prairies are

present along the southeast and northwest coasts of the island on

calcareous sediments. Illegal trawling within the 40-m zone has caused

significant loss of Posidonia oceanica meadows in recent years, together

with the damage caused by anchoring and recreational activities .

Sardinia / / Posidonia oceanica extends all along the Sardinian coast, from a few meters

to 30 m, and occasionally 40 m, depth. Prairies on the southern and northern

coasts of the island are more fragmented (author's unpublished data). FRANCE

Provence Alpes / / / / Posidonia oceanica is the most abundant species. Cymodocea nodosa:

Cote d'Azur dense monospecific meadow from to 15 m depth and mixed beds with

Zostera nottii and Caulerpa prolifera. Zostera manna: dense meadows

present in the Gulf of Fos, while small beds occur in the Bay of Toulon.

Zostera nottii is present in small patches in the Berre lagoon'""°". The western Mediterranean 53

this production is only minimally used for direct the removal of 1 m' of matte can cause 20 m of coastal consumption by herbivores'"'. The very high biodiversity regression"". Moreover, the of dead leaves found in Posidonia oceanica beds is mostly due to the ashore gives rise to a typical structure called primary role of this seagrass as a multidimensional "banquette" which, mixed with sand, can in some areas habitat for organisms directly participating in the develop up to 2-3 m high"". The banquette has an impor- system's trophic dynamics"". tant role in attenuation of waves and in the protection of

The Posidonia oceanica matte not only represents beaches from erosion'™. In addition, the banquette is a net sink of carbon and other elements'^"' but also, hosting a reduced, but highly specialized fauna lisopods, when growing near the surface, can attenuate the wave amphipods and interstitial ) that contribute to action. Under such conditions, it has been estimated that the decomposition of the seagrass material.

Sites Po Cn Zm Zn Hs Area Comments

Ikm-'l

Languedoc- / / / 26 Posidonia oceanica is present only in small patches between 7 and 15 m

Roussillon* depth, with dead and living beds 1 -4 km from the coast (extent not

available!. The region is charactenzed by the presence of many

coastal lagoons with monospecific Zostera manna beds leg. Salse lagoon]

or mixed beds with Zostera noltii (e.g. Thau lagoons). In open sea Zostera

no/fH occurs in small patches (e.g. Harbor of Banyulsl"^"".

Corsica / / / 624 Posidonia oceanica meadows on sandy bottom on the east coast and on

rocky bottom on the west coast. Dense Cymodocea nodosa meadows on

sand or muddy bottom in shallow bays and in lagoons. Zostera noltiiis only

present in lagoons, often in association with Cymodocea nodosa"'''".

SPAIN

Catalonia / / / / 40 h^ostly on sandy bottom, but also on rocky bottom. From near the surface

to 25 m. Conspicuous regressions have been reported, but most meadows

seem to be stabilized nowadays'"'.

Valencia / / / 270 This region has extensive meadows of Posidonia oceanica from near the

surface to 25 m, exceptionally 30 m, generally on sandy bottom. The deep

limit has suffered a signihcant regression due to illegal trawl hshing

(Sanchez-Lisaso, unpublished data).

Murcia / / / 95 The mam meadows are dominated by Posidonia oceanica, extending from

the surface to 25-30 m. Conspicuous regressions have been observed near

the deep limit due to illegal trawl fishing. Cymodocea nodosa and Zostera

no/(i/' appear in shallow waters'™'.

Andalucia / / / / Posidonia oceanica is abundant in the eastern part of the area, with

extensive meadows on sandy and rocky substrata. The western limit of

Posidonia oceanica is near Malaga; from this point westwards (to the

Gibraltar straitl, Zostera manna dominates"".

Balearic Is* / / / 750 Extensive and dense meadows occur all around these islands, reaching up

to 40 m depth, with some locally degraded sites, mainly due to

(moorings, sewage, etc.). One locality has been invaded by Caulerpa

taxilolia. In shallow bays, dense Cymodocea nodosa meadows are frequent.

Cymodocea nodosa is also found below 30 m'"'.

Notes:

Po Posidonia oceanica-, Cn Cymodocea nodosa; Zm lostera manna. Zn lostera nottii: Hs Haloptiila stipulacea.

/ species present. - insufficient data

• Interactions with Caulerpa taxilolia and Caulerpa racemosa. •'http://gis.cnuce.cnr.it/posid/html/posid.html 5A WORLD ATLAS OF SEAGRASSES

Case Study 3.3 dataset has one of the longest series for this species, SPAIN and the results show significant interannual differences. From the first observations in 1984 and CATALAN COAST 1987, density and cover decreased sharply (e.g. at

The main seagrass species on the Catalan coast is the 5 m depth station, density decreased from 628

Posidonia oceanica. In the sandy coasts of the ±19 shoots/m' in 1984 to 481 ±14 shoots/m^ in 1994,

southern part of the country this species forms a while cover decreased from 76 percent in 1984 to 48

large and continuous green belt of meadows only percent in 1994! probably due, at least in the shallow

interrupted by rivers. This seagrass belt used to station, to very high mooring activity on the seagrass extend from 10 to approximately 25 m depth, bed. However, after the establishment of the marine

although significant regressions have been detected reserve in 1990 anchoring was no longer allowed,

and in many areas the deep limit is now between 17 and a system of low-impact mooring was deployed and 20 m. Along the northern rocky coast, the between 1992 and 1993. The density and cover values

meadows occur from near the surface to 20-25 m. subsequently recovered (e.g. at the 5 m depth With the publication of an edict protecting station, density reached 708 ±24 shoots/m'' and cover

seagrasses in 1991, the autonomous government 73 percent in 2001!. Moreover, it would also seem

(Generalitat de Catalunyal has taken several actions that meteorological conditions (e.g. incoming

for a proper management of these plants and, more irradiance! in these later years have been optimal,

specifically, of the Posidonia oceanica meadows. probably contributing to the observed increase.

This includes a monitoring network, launched in 1998. This network consists of a total of 28 ALFACS BAY (EBRD DELTA)

permanently marked sites (nearly one every 15 km) Although Posidonia oceanica is the most abundant

from which basic data on the vitality of Posidonia seagrass species on the Catalan coast, in some

oceanica (e.g. shoot density, cover, etc! are collected specific habitats other marine angiosperms can

every year'^^'. is performed by dominate. This is the case in the two bays at each side

volunteers (more than 400 for the whole project!, of the Ebro Delta, the southern one of which (Alfacs

trained and supervised by expert scientists. This Bay! has been extensively studied and mapped. In this

monitoring network, after the first four years, has bay, 50 km^ in extent, dense meadows extend from

allowed a general diagnosis of both the status and very near the surface to 2-3 m and, more rarely, 4 m

the recent trends of seagrasses on the Catalan in depth. This narrow bathymetric range is due to high

coast. The results obtained so far indicate that A2 water turbidity™. Cymodocea nodosa, with the green

percent of the studied meadows are in a normal or alga Caulerpa prolifera interspersed in some places,

healthy state, while the rest show light (36 percent] dominates these meadows. Some patches of Zostera

or strong (22 percent! evidence of degradation noltii. as well as Ruppia cirrhosa. exist in shallow

During the four-year period of the survey there have areas. The presence of Zostera marina was detected

been no net changes in the Posidonia oceanica beds. in the early 1980s, but it has never been seen again. A

Only in 15 percent of the sites has a negative, detailed map was produced in 1986 revealing a total

although slight, trend been detected from a decrease surface of seagrass beds of 3.5 km^ including 1 km'

in water transparency, illegal trawl fishing and of patchy beds in the southern zone. In the last ten oversedimentation. Overall the Catalan seagrass years, the bay has undergone some remarkable beds appear to have remained remarkably stable vegetation changes'^". Cymodocea nodosa has greatly

over the period 1998-2001. expanded in the southern part of the bay, covering

now about 2.5 km' which represents, for this southern

MEDES ISLANDS area, an increase of approximately 15 percent a year The Medes Islands are a small and deserted This increase may be associated with work performed

archipelago situated 1 .6 km off Spain's main coast, in to stabilize the sandbar, since sand instability was one

the northern part of Catalonia. A large Posidonia of the main processes controlling seagrass

oceanica meadow, extending from 5 to 15-20 m abundance in this area™'. In the northern parts of

depth, and covering about 9 ha, is found in the Alfacs Bay, the most remarkable change is the

sedimentary bottom of the southwest face of the replacement of a mixed Zostera noltii and Ruppia

main islands"^'. This meadow has been extensively cirrhosa bed, described in 1982™, by Cymodocea

studied'^'' ^^' in the course of the monitoring program nodosa with abundant drifting macroalgae, such as

of the marine reserve established there in 1990. The Ulva spp. and Chaetomorpha linum, by 1997. The western Mediterranean 55

Mediterranean seagrass meadows host many commercially important fish species. As well as nurseries they provide essential feeding grounds for

cephalopods. crustaceans, shellfish and finfish'-". Although specific fisheries legislation does not allow

destructive fishing (e.g. trawling! in seagrasses, such restrictions are often violated. The only fishery allowed

in the Posidonia oceanica meadows are small fisheries based on the use of standing nets and cages.

Posidonia oceanica detritus is used as fertilizer in

agriculture in Tunisia'"' and the leaves have also been

used in small proportions in feed'"', with an in-

crease in egg production and weight. More recently,

different attempts to exploit the banquette were focused

on production of methane'^", conversion of detritus into

fungal biomass'"' and formation of dried pellet for prep- Posidonia oceanica growing on rocks and forming matte, Porto

aration of light bricl

uses of air-dried leaf detritus to protect glass objects in

transport, and to fill pillows and mattresses, have been which has become widespread in the last ten years.

reported. Posidonia oceanica detritus is used in Corsica Experimental work on the interactions between intro-

as thermal insulation material on roofs'^" and as sound- duced Caulerpa species and local seagrasses show that

proof material'"'. The ability of Posidonia oceanica leaves dense meadows of both Posidonia oceanica and

to produce active substances, which accelerate the Cymodocea nodosa are likely to be less affected by

growth of bacteria such as Staphylococcus aureus, has seaweed invasion. The competitive success of Caulerpa

been demonstrated. This seems to be related to the racemosa with Posidonia oceanica meadows is a presence of chicoric acid, one of the most abundant function of seagrass density and edge-meadow

metabolites found in this seagrass'™'. orientation. Competition between Caulerpa racemosa

and Cymodocea nodosa seems to favor the expansion of

THREATS Zostera noltil''"''''. The locations of interactions between

Beds of Posidonia oceanica have suffered a progressive seagrasses and Caulerpa spp. are listed in Table 3.2. regression throughout the Mediterranean due to Although Mediterranean seagrasses are now trawling, fisheries and sand extraction and development being increasingly well monitored, reliable estimates,

of coastal infrastructure'^""', such as harbors and made by direct observation, of the area of seagrass lost

artificial beaches, and associated enhanced turbidity or degraded by the various are not available

and sedimentation. The damming of rivers has caused for most of the western Mediterranean coastline. In fact

changes in sedimentation in the littoral zone, either only in the last few years have maps of distribution

exposing or burying seagrass habitats. One dramatic been produced. In the future the application of aerial

example occurred in Port-Man Bay (southeast Spain], cartography techniques may supply important where a was buried under a large information on seagrass status throughout the amount of highly toxic mining debris. Eutrophication, Mediterranean'"'". which decreases water transparency and promotes In general, for Posidonia oceanica. the following

epiphyte overgrowth, is a serious regional threat. statement by the European Union for Coastal

Sometimes associated with fish cages, the most com- Conservation is probably accurate: "The situation in the

mon causes are sewage and industrial waste discharge. Western Mediterranean is serious. Shoot density is

Cauterpa taxifolia is a tropical green seaweed rapidly decreasing, up to 50 percent over a few decades.

accidentally introduced in the Monaco area in 198i. After Besides, increased turbidity and pollution have resulted

its introduction, Cauleipa taxifolia spread through in a squeeze of the beds; in various places living beds

France, to Italy and Spam (the Balearic Islands! by 1992, have withdrawn between 10 and 20 m depth. Dead beds

and to Croatia in 199^"". The area colonized has now occur abundantly, even in waters which have already reached more than 60 l

coasts. Caulerpa taxifolia grows throughout the entire coast habitat loss is estimated at 10-15 percent; but

depth range of the Mediterranean seagrass species and, taking into account the decrease of shoot density the

in some places, is progressively overwhelming them. overall decline of the resource will be between 30 and

Another strong competitor with seagrass beds is the 40 percent. This is probably a good estimate for most introduced congeneric species Caulerpa racemosa, Western Mediterranean coastlines, although the 1 A

56 WORLD ATLAS OF SEAGRASSES

situation around the Islands and In the Eastern AUTHORS

Mediterranean Is better". G. Procaccini, M.C. Buia and M.C. Gambi, Stazione Zoologica "A. Dohrn",

In France a disappearance of Posidonia oceanica Laboratono di Ecologia del Benthos, 80077 Ischia INaplesI, Italy.

beds between and 20 m has been observed In the last Tel; +39 10181 5833508. Fax: +39 10181 984201 . E-mail: gproldalpha.szn.lt

30 years tor 13 percent of the seafloor In the Alpes

(Maritime departnnent, 6.6 percent in Var and 18. M, Perez and J. Romero. Deparlament d'Ecologia, Universitat de

percent In Bouches du Rhone'""". In Spain, a compari- Barcelona, Av. Diagonal 645 , Barcelona, Spam.

son of old nnarine charts with present distribution data

in Catatonia indicates that meadow area is now about G. Pergent and C. Pergent-Martini, Equipe Ecosystemes LIttoraux,

75 percent of that at the beginning of the 20th century. Faculty of Science, BP 52, 20250 Corte, France.

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4 The seagrasses of THE BLACK. AZOV, CASPIAN AND ARAL SEAS

N.A. Milchakova

The principal characteristic of the temperate Euro- water bodies, and has been especially damaging to the Asian seas is their total (Aral and Caspian) or traditional fisheries of these four seas. In the Caspian near-total lAzov and Blackl isolation from open and Azov Seas, which are of the greatest significance for ocean systems. These temperate seas have many commercial fishing in the region, the usable fish stock common environmental features especially with regard has been reduced by more than half. The largest to variable salinity and levels of pollutants. sturgeon stock in the has dramatically

Geographical proximity and isolation determine a decreased. In the last two years, the commercial stock number of special features inherent in these seas: they (approximately 250000 metric tons) of kilka, have a distinctly continental climate, no tides Ibut Clupeonella cuUriventris. has been reduced by 40 considerable long-term fluctuations of sea level, and percent. Twenty thousand Caspian seals and about 10 both coastal upvi^elling and downwelling, have million birds have died. High concentrations of heavy occurred), minimal or zero water exchange with other metals and oil products were detected in the dead seas and seawater of unusual chemical composition"^'. animals'".

All four seas contain the estuaries of major rivers and Seagrasses play a key role In the coastal eco- are consequently dependent on the influx of freshwater systems of the seas and occupy vast areas in the

In nearly every case these rivers have been severely shallow bays and gulfs of the Black, Azov, Caspian and disrupted from their natural state by the construction of Aral Seas. The diversity of algae, invertebrates and dams, and upriver pollution and water extraction, as fishes In seagrass communities is astonishing. The well as changes in rainfall across their watersheds. condition and distribution of seagrasses are strongly

Therefore long-term changes in seawater chemical influenced by freshwater influx, industrial, municipal composition and concentration have occurred near the and agricultural sewage, shipping, sea-bottom river mouths. Distinguishing hydrological charac- dredging, dumping, and oil and gas extraction on the teristics of the coastal shelves, the main potential shelf. Fluctuations in the sea level of the Caspian and habitat for seagrasses, are their shallow depth (about Aral Seas also influence the coastal ecosystems. 20 m) and large area, marked seasonal and interannual fluctuations in productivity, winter ice cover, pre- BLACK SEA dominant wind-induced seawater circulation, and fast There are four seagrasses, two seagrass associates water exchange owing to the small capacity and about 300 macroalgae In the flora of the Black

Highest productivity is found in the brackish areas Sea'". Communities of Zostera marina, Zostera noltii, of the north Caspian Sea, the northwestern Black Sea, Potamogeton pectinatus and Ruppia cirrhosa occupy and the and Kerch '^ ' ^'. This high vast areas in shallow bays and gulfs, especially in the productivity is due to massive freshwater influx from the northwestern part of the sea""". The distribution and Rivers Volga, Danube and Don, and the correspondingly ecology of Black Sea seagrass was first reported at the high nutrient input, fast turnover of these nutrients, beginning of the 20th century'" '^', with further details intense summer warming, high dissolved oxygen of seagrass biology and community structure in the content of the brackish water and the longer summer Black Sea, and environmental impacts on the '° daily growth period at higher latitudes. However, at the seagrasses, being obtained in subsequent decades'" '^ same time anthropogenic pollution substantially '". During 1934-37 communities of Zostera marina reduces the biological diversity and productivity of the were seriously damaged due to a wasting disease

im 60 WORLD ATLAS OF SEAGRASSES

Karkinitsky Gulf is 1 109 g wet weight/m' with a density of 105 shoots/m"''''. Lower biomass and higher density

occur in the Donuzlav Salt Lake 1836 g wet weight/m'' and 218 shoots/m'l'"'. Near the mouth of the Chernaya

River, where the salinity is less than in other parts of the Black Sea 111-17 psu). seagrass biomass reaches

2986 g wet weight/m" and density 1 136 shoots/m""', although the maximum biomass values recorded for the

Black Sea occur in Kamysh Burun Bay in the southern

part of the Kerch Strait (5056 g wet weight/m'l"°'. In the Kerch Strait, which links the Black and Azov Seas.

Zostera marina biomass ranges from 2008 g wet

weight/m' at Cape Fonar'"' to 3958 g wet weight/m' in Kerch Bay''", and plant density from 916 to 600 shoots/m' respectively. The longest shoots of Zostera

marina, at more than 2 m, have also been found in the

Early symptoms ot wasting disease in Zostera manna - an Kerch Strait''", though in other areas of the Black Sea

epidemic in the 1930s seriously damaged communities of this their length more typically varies between 25 and 100

seagrass in the Black Sea cm"^'". For Zostera nottii, biomass estimates vary from 0.5 to 2 kg wet weight/m'; the highest values were ""'". epidemic similar to that registered along the North registered at depths down to 1 m in summer''' Atlantic population of this species"". Fortunately, The total sea-bottom area occupied by Zostera

Zostera noltii, also widely found in the shallow bays and spp. in the bays of the northwestern Black Sea is more

'"'. , was not affected'" than 950 km", or AO percent of the total area of all the

During the 1970s and 1980s, the stock of Zostera bays""'. Zostera spp. communities cover a similar por-

spp. growing in the four largest bays of the Black Sea, tion, about 50 percent, of the sea bottom in shallow bays

the Tendrovsky, Dzhanlgatsky and Yagorlitsky Bays and of region, the Kerch Bay and Kerch Strait. the Karkinitsky Gulf, was estimated at 633 000 metric Though most investigators have acknowledged

tons"" "'. After 1982 the coasts of these bays that the recent eutrophication of coastal ecosystems of

accumulated considerable cast-off of Zostera spp., the Black Sea has led to degradation of key benthic and

estimated at 35 000 metric tons dry weight''". However, plankton communities""", the dynamics of the long-

according to previously calculated data on the annual term changes observed in Zostera spp. communities

leaf production of Zostera spp., the actual annual have revealed that there are many localities, including

estimate was about /1 000 metric tons dry weight. dumping grounds, where recovery of the seagrass beds

fvlany researchers have noted that Zostera spp. IS occurring. Estimates of Zostera marina biomass

usually grow in the coastal salt lakes and sometimes in have increased two- to threefold in Laspi. Kazachaya.

the deltas of the rivers'" "'. There is no information on Kamyshovaya. Streletskaya. Severnaya. Holland and

the distribution of Zostera spp. along the shores of Kerch Bays, and in the Kerch Strait, over a period from

Georgia and Bulgaria. Zostera noltii is found in Sinop 1981-83 to 1994-99"*"" '". The greatest increase in

Bay, on the Anatolian coast of Turkey biomass. from 1 185 to 3958 g wet weight/m'. has

Seagrasses in the Black Sea grow in single occurred in Kerch Bay. and the greatest increase in

species and mixed communities, located on and shoot density, from 252 to 936 shoots/m'. in

sandy sediments, often with a portion of shell grit. The Streletskaya Bay. This increase in the yield of Zostera

depths at which they are found range from 0.5-17 m, spp. biomass Is probably due to several factors, the

across a salinity gradient of 0.3-19.5 psu. Some 115 most significant of which Is likely to be reduced

algal species have been identified growing in Zostera industrial pollution and the natural resilience of

marina communities, and 62 in communities of Zostera Zostera marina and Zostera noltii to environmental noltif™'. The majority of the algae are epiphytes changes. According to unpublished data obtained by the encrusting the leaves and occasionally the rhizomes Southern Research Institute for Fishery and

and roots. Cladophora, Enleromorpha. Ceramium. Oceanography In Kerch, the amount of Zostera spp. in

Polysiphonia and Kylinia spp. predominate. There are meadows in the Karkinitsky Gulf has also increased,

more than 70 species of invertebrates, 3^ fishes and 19 despite extensive annual excavation of sand. fish larvae in seagrass meadows, among which My own observations indicate that self-

shrimps, scad and perch predominate'"'. restoration and enlargement of Zostera beds is

The average biomass of Zostera marina in occurring in Sevastopol. Kerch and Bays, all of The Black, Azov, Caspian and Aral Seas 61

30" E 6q"E — Minor Bavs and Sea \SyrcJa/ya UKRAINE 50" N KAZAKHSTAN SivBsh National Nature Park Obitodiny ,,. , Maloclmy / Sail Like / /Betosaraisky RUSSIAN FEDERATION - - Mangy'shliikxh' Ba\- TendrmvUy Buyi ^ \ urtm / ;rBerdyansky

V' Wi— KercliSr ^^ lull Darvbe Delta \ ^ ^ •MaMiadikala Bio^ihew Reserve- Sevaslopolt^y lruft

'i Doiiirztuv Sair itiAi' CASPIAN

S E I TURKMENISTAN JKrasnovodsky Bay SLACK si;. I

; litikiiBui

Tuiiriicn^kf Bar

TURKEY 100 200 300 400 500 Kilometefs

Map 4.1

The Black, Azov, Caspian and Aral Seas which have been subject to considerable disturbance extensive and dense compared with other seagrasses. from recreational activities. Indeed not only seagrass This species grows on silt-sandy sediments with shell but all Black Sea benthic macrophytes are stabilizing grit from 0.2 to 8 m'""' and across a salinity gradient of and recovering from recreational pressures over wide 2-26 psu. Zostera marina inhabits the same depths but areas. In contrast seagrass and algae communities are covers a considerably smaller area. Zostera spp, grow In most degraded in areas with heavy sedimentation singte-species beds and also in mixed communities with loads. This decline has occurred particularly along the other seagrasses, mostly Potamogeton pectinatus and deepest boundary of macrophyte growth. Ruppia cirrhosa. and with algae such as Ceramium, Black Sea Zostera spp. are traditionally used In Polysiphonia. Ciadoptiora and Enteromorptia spp. local agriculture as a forage additive and for winter Zostera noltii and Zostera marina are found almost

Insulation for barns for livestock'"'. It has been proved everywhere along the shoreline of the sea'"', and also in experimentally that the daily yield of milk of cows the coastal salt lakes, river mouths and floodplains. This whose fodder was mixed with Zostera marina is due to their tolerance to salinity fluctuations. Zostera Increased by 15-20 percent. Weight Increases of 20-30 noltii in the Sea of Azov has shoots 15-70 cm long, while percent In fed Zostera. and of 10-15 percent in those of Zostera marina measure 20-90 cm. pigs'"', have also been observed. Seagrass additives The vast meadows of Zostera noltii and Zostera appear to increase milk quality and fat in cows manna predominate in the northern part of the sea, and provide better quality and quantity of sheep wool. close to sandy spits, and in the coastal salt lakes. Zostera spp. are a valuable source of pectins, aquatic Communities of Zostera noltii are also widely prevalent which produce firm gels. Being rich in in the eastern Sea of Azov, while Zostera marina is hemicellulose and pectin substances, seagrasses are found here only in patches''*'^". In the western part of also used as a gluing component in mixed fodder the sea, Zostera spp. are rare, being usually found as granulation and packaging. solitary sparse seagrass beds. Along the southern

In the Black Sea, seagrasses have been placed coast Zostera spp. are dispersed. Zostera spp., washed under protection in ten nature reserves under the ashore after the leaf fall, abundantly cover the coast. national control of Ukraine and Romania'^"-^*'. The The annual commercial after-storm harvest amounts largest of them are the Danube Delta Biosphere to about 1 200 metric tons dry weight. Reserve and the Chernomorsky National Reserve. Recent field measurements have recorded the blomass of both Zostera species around the Sea of SEA OF AZOV Azov. Zostera noltii blomass in the bays (wet :

There are four species of seagrass, three seagrass Arabatsky 1 197 g/m^ Kasantyp 28A g/m^ Tamansky associates and 6A macroalgae in the flora of the sea"". 374 g/m', Betosaraisky 860 g/m', Obltochny 1 180 g/m' The Zostera spp. have a Mediterranean origin and are and Berdyansky 400 g/m'l is generally comparable believed to have appeared In the Sea of Azov in the with the salt lakes (wet weights: Sivash

Paleocene'"'. 1 157-1 400 g/m*', Molochny 378 g/m' and Utlyuk 667

The meadows of Zostera nottii are the most g/m'l but higher than the seaward coasts of the large 62 WORLD ATLAS OF SEAGRASSES

noltii v/ere sand spits which are such a feature of the Sea of species and mixed communities of Zostera grit never on a Azov Iwet weights: Belosaraiskaya 28 g/m'. Fedotov 30 found on sand sediments with shell but g/m^ Obitochnaya A5 g/m" and Berdyanskaya silt bottom. Highest productivity takes place in mixed of Zostera noltii and Charophyceae, 30 g/m^r"'"''"'"-''''"'"'. The biomass of Zosfera manna communities Chara, was also measured at three of these locations: in Ruppia and Potamogeton spp. Species of Polysiphonia. Laurencia, Enteromorpha Sivash (2000 g wet weight/m'l and Molochny (592 g wet Ceramium, beds. weight/m^l salt lakes and Tamansky Bay (219 g wet and Cladophora are common algae in seagrass distribution of seagrasses and macrophytes weight/m^ at 1 m depth but more than ten times this The markedly in the period at 3.5 ml. in the Caspian Sea changed extensive Analysis of the long-term dynamics of the 1934-61 to 1967-81. In the 1930s there were coasts, principally structure of Zostera communities indicates that, Zostera noltii beds along western Azerbaijan, with despite changes in the environment and increased Baku and Kirova Bays in present-day eutrophication, the recent 60 years have not been records indicating the presence of this species at marked with radical changes. For example, in the late , Izerbesh and Makhachkala, and in Russia. 1930s, the biomass of Zostera marina in Utlyuk Salt Astrakhansky and Kizlarsky Bays in modern Mangyshlaksky, Lake was estimated to range from 213 to 2 2^2 g wet Along the eastern coast Kaidak, Bays, and the Mangyshlak weight/m'™ and in the early 1970s from 333 to 1 024 g Kazakhsy and Turkmensky wet weight/m'"". Furthermore, over the past 30 years, Peninsula, were the main locations of mixed Zostera, of the the biomass of Zostera noltii in Utlyuk Salt Lake has Ruppia and Potamogeton beds. Estimates cirrhosa in the increased from 260 to 667 g wet weight/m'""'. biomass of Zostera noltii and Ruppia in the The local population traditionally uses Zostera Caspian Sea at this time were much higher than with the salinity of the spp. cast-off to insulate housing, for livestock during present day. In Kaidak Bay, winter and as an efficient means of deterring rodents in seawater ranging from 25 to 51 psu, the highest salinity noltii. biomass of barns. The high silica content of this material reduces level ever documented for Zostera the to be 7 000-8000 wet Its flammability and therefore its risk as a fire . It Zostera noltii was estimated g has been experimentally proved that dried Zostera weight/m' and that of Ruppia cirrhosa 10000-12000 g '"•'. of Zostera noltii from marina mixed with urea is a valuable forage additive for wet weight/m' The shoots livestock. Kaidak Bay were 75-100 cm long, while in the open sea

Seagrasses of the Sea of Azov have been placed the length was 25-30 cm. In comparison with Kaidak under the protection of many international conventions Bay, in the open sea the biomass of this species was and the state laws of Ukraine'^*'. They are the object of substantially less, varying from 100 to 1500 g wet of Zostera noltii for the protection in seven nature reserves, the largest of weight/m". The total stock which are Sivash National Nature Park and the coastal Caspian Sea was estimated at approximately 700000 Molochny Salt Lake. metric tons (wet weight], with about 500000 metric tons for the eastern and 200000 metric tons for the CASPIAN SEA western coast. The area covered by the seagrass in just Three species of seagrass. two seagrass associates the northeastern Caspian Sea was 1 650 km'. and 65 macroalgae make up the submerged flora of the During the 1950s coastal configurations changed Caspian Sea'^". The earliest work on the composition and many shallow bays such as Kaidak Bay, in which formerly and distribution of Caspian Sea seagrasses was Zostera noltii and other macrophytes the area of others such as produced in 1784'"' but it was not until the 1930s that flourished, vanished and

the most comprehensive reviews on the topic were Krasnovodsky Bay decreased substantially'' . Ever published'""'. This was the first time that the since that time. Zostera no/t// communities have been hypothesis about Zostera noltii s penetration into the degrading, having almost completely vanished along Caspian Sea from the Black and Azov Seas was the western coast and becoming seriously depleted in advanced. Presumably Zostera noltii was introduced the east. In 1935-38 the biomass of Zostera no/(// along from the Mediterranean to the Caspian Sea in the the eastern coast ranged from 50 to 8000 g wet Paleocene, 36-65 million years ago. At that time the weight/m-'" "'. By 1971-74 the range had decreased to Black Sea. the Sea of Azov and the Caspian Sea were 50-1 300 g wet weight/m''""", and in the early 1980s it '"'. connected by the Kumo-Manych Strait. was 127-1 340 g wet weight/m'' Despite the decline Zostera noltii communities were then widely in biomass the area of some beds in Krasnovodsky Bay distributed throughout the Caspian Sea"^' " "', typically enlarged considerably, so much so that in the early at depths of 2.5-4.5 m along eastern shores, though 1970s different experts evaluated the stock of Zostera i\K occasionally as shallow as 0.5 m and as deep as 18 m. noltii \n Krasnovodsky Bay to be 200 000-440000 metric across a narrow range of salinity, 12-13 psu. Single tons wet weight. Apparently, such an expansion may be The Black, Azov, Caspian and Aral Seas 63

due to environmental changes and the drop in sea level noltii and estimates of its biomass have increased in which brought about the extinction of competing algae the northern bays, while in the more brackish area such as the Charophyceae. near the Syrdarya 's mouth biomass has considerably At present, available data indicate that Zostera decreased. Records from the early 1990s show that noltii is only rarely found in the western Caspian Sea at biomass is now apparently positively correlated with

Makhachkala and in Kizlarsky Bay Seagrasses have salinity. In the Syrdarya Estuary at salinity of 7 psu completely disappeared from the southern Caspian biomass was just 42 g wet weight/m", whereas in

Sea''' ^". Single and mixed communities of Ruppia Tshe-Bas Bay Zostera noltii not only tolerates salinity spp. are found growing in Astrakhansky Bay in the west as high as 45 psu but thrives on silt-sandy and sandy and in Komsomolez, Kazakhsy, Krasnovodsky and sediments supporting beds with biomass of 2258 g

Turkmensky Bays in the east, on silt sediments at wet weight/ml Intermediate values were observed in depths from 0.5 to 3 m. the Berg Strait 1417 g wet weight/m" at 23 psul,

Though the areas of sea bottom covered with Butakov Bay 1899 g wet weight/m' at 36 psu) and seagrasses have substantially declined, they are still Shevchenko Bay II 076 g wet weight/m' at 30 psul'"'. important in the ecology of the Caspian Sea. Seagrasses As the continues to disintegrate, Zostera play an important role in the nutrition of invertebrates noltii communities are expected to persist mostly in on which the state of commercial fish stocks depends" bays of the Minor Sea, where the sea level has ''". In the northern Caspian Sea, Zostera no((//growth is remained constant for the past decade. of special significance, because this is where wild carp, Total macrophytic stock in the sea is estimated at Caspian roach, bream and other valuable fish 1.34 million metric tons wet weight. The share and feed'". Other seagrasses are the usual food item for contributed by Zostera noltii is about 8.1 percent waterfowl. Ruppia spp. constitute up to 25 percent of the 1109000 metric tons wet weight], while algae such as intestinal content of swans and gray geese and 5A-QA Charophyceae and Vaucheria dichiotoma contribute percent of that of ducks. 77.6 and 13.4 percent, respectively'^".

The seagrass communities have been placed Compared to phytoplankton, macrophytes such under protection in two national nature reserves as Zostera noltii are of little importance in the food (Astrakhansky and Krasnovodsky National Reserves). chains of the Aral Sea. However they are ecologically important. The meadows of Zostera noltii are the ARAL SEA spawning location of diverse invertebrates and fish. There are two seagrasses, Potamogeton pectinatus Benthic invertebrates and fish predominantly feed on and 16 macroalgae in the flora of the Aral Sea'™'. diatoms [Navicula spp. and Merismopedia spp.) and are

Presumably Zostera noltii was introduced from the found in abundance'^' ""' However, during the past 50 t^editerranean to the Aral Sea, also through the Kumo- years, the catches of commercial fish have collapsed to l^anych Strait. The most extensive knowledge about the point where the Aral Sea has almost lost its seagrass distribution had been acquired prior to the significance for fisheries. severe anthropogenic disruption of the Amudarya and There are no data regarding nature reserves

Syrdarya river systems in the mid-1950s'^" that caused along the coastal zones of the Aral Sea. catastrophic changes to the ecosystem of the Aral Sea and adjacent water bodies. ACKNOWLEDGMENTS

Zostera noltii grew from 0.1 to 10 m deep, with I am grateful to Prof. R.C. Phillips (Marine Research Flonda Institute), most growth being concentrated at 0.1-2 m depth in O.A. AI(imova. G.F. Guseva, M.Yu. Safonov IIBSS), Dr I.I. Serobaba

^". the northern shallow bays'*' In the mid-1950s, the lYugNIRO), Dr I.I. Maslov jNikita Botanical Garden) and Ms Olga biomass of Zostera noltii was estimated to be 17 to Klimentova for their help in preparing this chapter

800 g wet weight/m% with the largest values registered near the mouth of the Syrdarya Riven In AUTHOR recent years, the environmental crisis which is wiping Nataliya A. Milchakova, Department of Biotechnologies and out a large part of the Aral Sea has manifested itself Phytoresources, Institute of Biology of the Southern Seas, National in drastic increases in salinity which, in turn, have led Academy of Sciences of Ukraine, 2 Nakhimov Ave., Sevastopol 99011, to changes in the biological components of all , Ukraine. Tel: +38 101692 544110. Fax: +38 10)692 557813. E-mail: ecosystems. However, the areas occupied by Zostera milchalSibss.iuf.net

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2 MatishcvGG, DenisovW[19991, Ecosystems and bioresources ol Publishing, Moscow jin Russian).

I I 64 WORLD ATLAS OF SEAGRASSES

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marina L, in Kerch Strait, Bull Nikitsky Botanical Garden 76: 26-27. crisis in the Aral Sea"] 250: 21-37 [in Russian]. The eastern Mediterranean and the Red Sea 65

5 The seagrasses of THE EASTERN MEDITERRANEAN AND THE RED SEA

Y. Lipkin

S. Beer

D. Zakai

This chapter Is divided into two sections and seagrasses on the Turkish and Greek northern Aegean considers the seagrasses of the eastern coasts'"^"' do not include Zostera marina among the Mediterranean and the Red Sea. While the seagrasses of this area. The only report of this eastern Mediterranean has a relatively restricted range seagrass from Egypt'" "' - the latter reference being

of species, the Red Sea is home to 1 1 species, all of based on the former - was probably a case of

tropical origin. misidentlficatlon; In later papers on Egyptian Mediterranean seagrasses, Aleem did not mention EASTERN MEDITERRANEAN Zostera marina. However, Tackholm ef al."" reported Early contributions from the eastern Mediterranean that the filling of an ancient Egyptian mummy was reported on the presence of Cymodocea nodosa lalso composed of Zostera marina, which indicates that the reported as Cymodocea aequorea or Cymodocea plant must have occurred, or was even common, in major], Posidonia oceanica lalso as Zostera oceanica], shallow Egyptian waters some 2000 years ago, and Zostera marina and Zostera noltii lalso as Zostera seems to have gradually disappeared, first from the

nana], in Greece, Syria and Egypt. Halophila stipulacea, warmer southeastern corner, then from wider and

a migrant from the Red Sea, v\/as first reported in the wider areas in the eastern and central parts of the

Mediterranean from the island of Rodos late in the 19th eastern Mediterranean, and remained until rather

century'". LIpkIn'' " summarized Its distribution In the recently on Its coldest, northernmost coasts. A similar Mediterranean through the early 1970s: during the last retreat from a former, wider range seems also to have three decades Halophila stipulacea has spread further, occurred with Zostera noltii, which is concentrated

mostly In the eastern basin (e.g. Methoni and Paxol mainly In the with considerably less

Islands, Ionian Sea" ^'; Marmaris'"'; Korinthiakos representation In other parts of the northeastern

'". Kolpos"", but also at and near Sicily"" Mediterranean, and almost none In the south. It has

The most common seagrass in the eastern disappeared, or become very rare, even in the south

Mediterranean Is Cymodocea nodosa. It occurs on all Aegean Sea'"'.

coasts of this basin on sandy and, less frequently, muddy bottoms. The next most prevalent seems to be Ecosystem description

Posidonia oceanica. a climax seagrass. In many regions Cymodocea nodosa and Zostera noltii usually grow in

In the northern part of the basin the balance between shallow water, from a few centimeters to a depth of 2.5-

the two is inverted, with Posidonia oceanica becoming 3 m lit has been reported that Cymodocea nodosa

the more common. The third in abundance appears to occupied a depth range of 5-10 m In the Bay of

be Zostera noltii and the least common Halophila LImassol, Cyprus'^"^'). Posidonia oceanica is found from

stipulacea. Zostera marina, a species common in the the shallows, where the tips of the leaves reach the

western Mediterranean, seems to be rare In the surface, down to 35-40 m. Halophila stipulacea, many

eastern part, if it still exists there at all. Collections of beds of which also occur in the shallows, e.g. at Rodos,

the latter species reported by den Hartog"'^' were from penetrates much deeper water. Bianchi ef al.''''"

the northern parts of the Aegean Sea, made In 1854, reported it as the deepest seagrass In the Bay of 1891 and 1910. Publications later than 1930, by Greek Limassol, growing at 25-35 m Ifor Posidonia oceanica and Turkish authors'" "', reported Zostera marina from they reported a range of 10-30 m). Fresh, seemingly in the same area. Interestingly, more recent papers about situ, material was dredged from around 145 m off

u 66 WORLD ATLAS OF SEAGRASSES

occurs at greater depths, on sandy bottoms. Zostera

nottii (reported as Zostera nana] was represented by scattered plants; no beds are recently reported.

Halophila stipulacea was rare in Ionian Greece around

1990, occurring at two sites only, at about 2.5 m depth

at Methoni, together with the siphonous green alga

Caulerpa prolifera, and at Paxoi"""'.

Most seagrass beds in the eastern Mediterranean are composed of one seagrass species only. Beds of Posidonia oceanica are usually very dense. Only when

they start to deteriorate, for example when affected by pollution, do other marine plants, usually algae, invade.

In Cymodocea nodosa beds, the seagrass is occasionally accompanied by Caulerpa prolifera. which may reach 20

percent of the plant cover"". Mixed populations of Posidonia oceanica and Cymodocea nodosa"'"' or Zostera

noltii ar\(i Cymodocea nodosa™ also occur.

Egypt Reports on seagrass habitats and community

structure in the eastern Mediterranean are scanty,

Boundary of Ponaorua uccanica meadow wiiii Cymodocea nodosa compared with the information available on these

growing on sand subjects in the western basin. The seagrass vegetation of the bay at Marsa Matruh Harbor (western end of the

Cyprus; however, below about 50 m it was rather Mediterranean coast of Egypt! and its close vicinity was scarce'^ described by Aleem in the early 1960s"". He reported

All four seagrasses grow in the eastern healthy beds of Cymodocea nodosa. Halophiila

Mediterranean on soft bottoms, quartz sand in shallow stipulacea and Posidonia oceanica and provided a waters and mud at greater depths. Cymodocea nodosa distribution map. In 1957-60, Cymodocea nodosa beds

frequently occurs in small sandy pockets that covered a continuous belt 10-40 m wide and about

accumulate in crevices or small depressions on rocky 750 m long in the inner part of the bay at a depth of

flats, and Posidonia oceanica is often found on rough around 50 cm to 2 m, on the slope between the substrates such as and gravel and even solid watermark and the horizontal bottom that starts at 2

rock. It is noteworthy that Halophda stipulacea, m. At the innermost part of the bay. the belt broke into

growing in a wide range of environmental conditions in scattered patches. In extremely sheltered areas, the

the northern Red Sea, including all kinds of coastal seagrass was absent. Right below this belt, on the

substrates"", has a much narrower ecological range in lower parts of the slope at 2-8 m depth, a belt of

the eastern fvlediterranean, being restricted in this l-latoptiila stipulacea of similar size occurred.

basin to soft substrates only. The form with bullate Posidonia oceanica formed a bed 70-120 m wide and

leaves, the so-called "buUata" ecophene, so common in about 300 m long, outside the inner bay, in an area

extreme conditions in the northern Red Sea, has not more exposed to winds and waves. been reported from the eastern Mediterranean. Several At El Daba, about 160 km west of Al Iskandariya

ecotypes of Halophila stipulacea occur in the northern (Alexandria). Posidonia oceanica covered a small area

Red Sea"*'. Probably only one of them has penetrated along with a few small patches of Cymodocea nodosa. and spread into the Mediterranean. Halophiila stipulacea did not occur at this site. The

Seagrasses occupy extensive areas in Greek macrofauna and algal macroflora were also scarce,

waters"". Clusters of Cymodocea nodosa appear in very both in numbers of species and in numbers of

shallow water only a few centimeters deep, mostly in individuals. For example, only 12 epiphytic algae were

sheltered areas, and to a lesser extent on beaches found on the leaves and rhizomes of Posidonia

exposed to winds and waves. In sheltered areas, oceanica"'-'-'".

Cymodocea nodosa tends to occupy deeper bottoms Aleem"" described in detail the establishment,

and form larger beds. In the southern Ionian Sea, such development and stabilization of the seagrass beds at beds appear from a depth of 60 cm down to 1.5-2 m. In Al Iskandariya. His description was later incorporated

shallower water, the plant is found on sandy bottoms, by den Hartog"" into his account of the ecology of

and a little deeper on muddy ones. Posidonia oceanica Posidonia oceanica. and therefore will not be repeated

.*>:

IT E N E

The eastern Mediterranean and the Red Sea 67

• • ITALY GREECE 80 160 240 320 400 Kilometers ** ^^ ^^ A ^ • Thermalkosy • *? AEdEAN TURKEY * SE 1 _.b "•" Koriiilhiaka. Izmir Korfeii Kolpos ,

IONIAN SEA .'

• Methoni • ri*'' f'i'"-^ ,,

>• Miios " ,,; Pholegandros f^^^ isi^j % Al Ladhiqiyah sYRIA •

• CYPRUS Tartous * Ras ibn Hani 35" N • Al

'-^'^°'' M E D 1 T E R R A N E A N SEA Savda .

Akkoff

ISRAa ^Bur Sa'id

, LIBYA • El Arlsh JORDAN Bardawfl EIDaba' ==^""'"' 20' 25- E EGYPT 30- E 35-

Map 5.1

The eastern Mediterranean Sue: Canal it)" E 4i>''b vEI Suweis -. \ ^

••Al' Aqabah (Elat) \ \

"^ ' Smai - Gulf ij/Aquha l\ here. At that time (the 1950sl, however, the Posidonia

/ • oceanica beds, once established, persisted for long R^ ^ iuhanvnad 1 Gulf of » Suez periods of time. Later, as in some other Mediterranean y \ fc sites, they became affected by domestic and industrial \ pollution and started to dwindle'"'. 25- \ % SAUOl ARABIA The coast of Sinai and the southern part of the EGYPT \ Israeli coast are mostly covered with pure quartz sand, with only a few rocky outcrops here and there. This part V

of the eastern Mediterranean coast, lacking bays and f t. Joddah coves, is highly exposed to wind and wave action. Wide * ked\ Cymodocea nodosa beds occur at depths of 2 m and SEA ^ more, along the Sinai coast, below the littoral belt in which the bottom sediment is intensively worked by the

breakers. A few small stands of Posidonia oceanica were reported by Aleem"" from the several rocky SUDAN habitats between Bur Sa'id and El 'Arish; the status of

, _Dalilai, these sites has not reported since 1955. \ been c<^'"»l»'"'^» YEMEN ERITREA . J Sabkhet el BardawTl, the large lagoon on the 15°N s \ Mediterranean coast of Sinai, harbors a large bed of

Ruppia cirrhosa, which covers up to a third of the lagoon'"'. The size of this bed fluctuates considerably I ETHIOPIA , ., 100 200 300 KllometefS , seasonally, and during severe winters it may disappear Xtuiidiil' completely. Map 5.2 The Red Sea Israel

Along the generally exposed Israeli coast, rich beds of level. All Cymodocea nodosa populations are subject to

Cymodocea nodosa are found on sandy bottoms at large seasonal and year-to-year fluctuations in size, on sheltered sites. The best developed is at Akko, at the occasion disappearing completely, eventually to renew

northern end of Bay. Small patches of the from the seed stocks in the sediment'^". Area estimates seagrass also occur in sand-filled depressions on for Israel are very approximate since no exact mapping submerged horizontal platforms just below mean sea has been carried out. We estimate the total Israeli

Vr' 68 WORLD ATLAS OF SEAGRASSES

Mediterranean coast populations of Cymodocea nodosa Turkey

to be no more than a few Inundred square meters. Along the Turkish coasts, at the eastern part of the Mediterranean coast, meadows of Posidonia oceanica Lebanon dominate the lower levels of the infralittoral zone, but

From the Lebanese coast there is no information about no further information about them is available, except

seagrass beds except that gathered by J.H. Powell on that Cymodocea nodosa and Zostera noltii have also

the occurrence of a Cymodocea nodosa and Halophita been found in the area"". On the Aegean coast, stiputacea bed some 800 m off Saida ISidon), in which monospecific beds of Posidonia oceanica and of the former comprised 70 percent of the seagrass Cymodocea nodosa were reported from Izmir Bay cover'^'. To judge from the very few records of llzmir Korfezi), as were mixed beds of the two.

seagrasses from the Lebanese coast, seagrass beds Cymodocea nodosa beds were 20-50 m in diameter, are uncommon. whereas those of Posidonia oceanicawere much larger

- 150 m and more in diameter'^". Similar meadows are Syria probably common on the Aegean Turkish coast. On the Syrian coast, too, seagrass beds are un-

common'"'. Cymodocea nodosa and Zostera noltii beds Greece are found near the river mouths between Tartous and From Greek waters, Bianchi and Morn"" reported

Banias, in the vicinity of Jable, in small, relatively calm dense monospecific stands of Cymodocea nodosa and

embayments north of Al Ladhiqiyah (Latakial and near of Posidonia oceanica at the island of Kos, in the

the harbors of Tartous, Al Arwad and Al Ladhiqiyah, eastern Aegean, the latter seagrass appearing to be

where they grow intermingled with Caulerpa scalpetli- more common. In the western part, large seagrass

formis and/or Caulerpa prolifera'"'. Zostera noltii beds were reported from the islands of Sikinos, Milos

appears also as an accompanying species in the plant and Pholegandros. Vast beds of Cymodocea nodosa

community dominated by Caulerpa scalpeltiformis at were found on mud in shallow bays at the latter two Tartous and Al Arwad. localities, at 0.3-4 m depth. Posidonia oceanica was

These seagrasses grow on this coast on clayey common on sandy deposits around the entire coast of

sand rich in organic matter They seem to tolerate all three islands studied, not just in bays. In shallower

considerable variations in salinity. Posidonia oceanica water they formed isolated tufts and in deeper water. 2-

is rare on the Syrian coast; Mayhoub'"' found it in only 8 m or more, they formed quite large beds""'.

two localities: northwest of Al Arwad , and in a bay

near Ras Ibn Ham. In both cases, the beds were not well RED SEA

developed; in his opinion they were in the process of Historical and present distribution

disappearing. He assumed that the rapid degradation The Red Sea harbors 11 seagrass species, all of

of the Posidonia oceanica beds northwest of Al Arwad tropical origin, which penetrated through its relatively

Island, a great part of which were already replaced by narrow mouth at Bab al Mandab. These are: Halodule Caulerpa, was the result of large sewage installations uninervis, Cymodocea rotundata. Cymodocea that had been constructed a short while previously at serrulata, Syringodium isoetifolium, Thalassodendron nearby Tartous'"'. ciliatum, Enhalus acoroides, Tlialassia hemprichii,

l-lalopliila ovalis, Halophita ovata, Halophila stiputacea

Cyprus and Halophila decipien^^^-''''-^K Only a single plant of Seagrass beds are widespread around the island of Halophila decipiens has hitherto been reported from

Cyprus. Rich stands of Posidonia oceanica and the Red Sea, grabbed from 30 m'''°'. For early records

of Cymodocea nodosa are common at different and distribution see Lipkin'"".

depths, Posidonia oceanica beds descending much Enhalus acoroides seems not to reach much deeper than those of Cymodocea nodosa. Mixed beyond the Tropic of Cancer, whereas the other ten

populations are found, but less often. Halophita species continue to the northwestern part of the Red

stiputacea beds are not as plentiful as those of the Sea proper, but only seven (the above listed species other two; they also descend to considerable depths'^'. excluding Enhalus acoroides, Cymodocea serrulata, The quickly expanding green alga Caulerpa racemosa Halophita ovata and Halophila decipiens] penetrate into

is considered a threat to the Posidonia oceanica beds. most of the Gulf of Elat (Gulf of Aqabal and only five

Since first noticed in the island in 1991, it has spread, [. Halophila stiputacea, Halophila unchecked, into a wide range of habitats from the ovalis, Halophila decipiens and Thalassodendron

shallows to depths of at least 60 m, on sandy as ciliatum] into much of the . Hulings and well as muddy bottoms, competing directly with Kirkman''"' reported Cymodocea serrulata from "a

Posidonia oceanica"''''^'. shallow lagoon on the west coast of the

-17 The eastern Mediterranean and the Red Sea 69

AO km south of Eilat", but this record should be confirmed. Halophila stipulacea, Halodule uninervis and Halophila ovalis appear at present to be the only seagrasses that reach the tips of these gulfs"'™"', although old records also listed and Syringodium isoetifolium from El Suweis

(SuezI, at the tip of the Gulf of Suez, and from Af

Aqabah at the tip of the Gulf of Elat, and in addition listed Cymodocea rotundata and Cymodocea serrulata from El Suweis'"''. Notably, Aleem'"' did not find any seagrass at Bur Taufiq, near El Suweis.

Halophila stipulacea, very common in the northern part of the Red Sea, is rather scarce at its central and southern parts'"^^', as well as at the tropical east African coast south of the Horn of Africa. It becomes common again on the east African coast near the Tropic of Capricorn"". Thus, Lipkin'"'concluded that this species is of subtropical affinity rather than tropical.

Some of the Red Sea seagrasses occur in the interlidal zone and most species usually grow at the shallow subtidal, not deeper than 5 m, but may be found as deep as 10 m'^' '*'. However, Halophila stipulacea is widely found in the Gulf of Elat at depths The northern Red Sea taken from the Space Shuttle. The Red Sea down to 50 and even 70 m and Thalassodendron harbors 1 1 seagrass species - all of tropical origin. ciliatum down to 30 m'" "'. In the Gulf of Suez,

Halophila dec/p/ens was found at 30 m. Halophila ovata Lipkin'^''', including information about the typical down to 20 m and one of the populations of Halophila accompanying fauna. Below is a summary of the few ovalis at 23 m'"'. On the Jordanian coast of the Gulf of available descriptions of the seagrass vegetation in

Elat, two Halophila ovalis stands were found at 15 and some Red Sea localities. 28 m, respectively'^-'.

Ivlost seagrasses in the Red Sea grow on mud, silt Eritrea or fine coralligenous sand, or mixtures of them. The In the south, within the Dahlak Archipelago, on the eurybiontic Halophila stipulacea and, to a lesser extent, Eritrean coast, seagrasses are not common. A sparsely Halodule uninervis thrive on a wide variety of vegetated Caulerpa racemosa-Thalassia hemprichii substrates. Thalassodendron ciliatum and Thalassia community was reported from sandy patches at the hemprichii, however, seem to prefer coarser substrata, lowermost intertidal zone'™'. Small patches of that is coarse sand admixed with coral and shell debris Halophila stipulacea and Halophila ovalis were also or even rather large pieces of coral from the found in the archipelago'*". surrounding fringing reefs or coral knolls at sites exposed to considerable water movement'""^^'. Saudi Arabia

Almost all beds of Thalassodendron ciliatum and For the central part of the Saudi Arabian coast, in the

Enhalus acoroides are monospecific, whereas Jeddah area, Aleem"" reported in the late 1970s that Syringodium isoetifolium, Thalassia hemprichii and Thalassodendron ciliatum, Syringodium isoetifolium.

Halodule uninervis often occur in multispecific Enhalus acoroides, Halophila ovalis and Halophila seagrass communities. This tendency also changes stipulacea grew predominantly as pure stands, but geographically, e.g. Syringodium isoetifolium forms were sometimes mixed with other seagrasses. He monospecific stands as well as occurring in remarked that Thalassia hemprichii, Cymodocea multispecific communities on the central Saudi Arabian rotundata and Halodule uninervis {ended to form mixed coast, whereas in the Gulf of Elat it was found only in communities. Thalassodendron ciliatum beds, to 20- mixed populations. 30 m' in size, grew on coarse coralligenous sand with

Although seagrass beds are common in the Red shell debris and sometimes on dead corals that were

Sea. information about the seagrass habitats and plant covered by a thin layer of sand. These stands of the communities in this basin is very limited. A general seagrass appeared at about 2 m or a little deeper'"'. account of Red Sea seagrass beds was given by Beds of Thalassia hemprichii, to 100 m' in size, were

Tf 70 WORLD ATLAS OF SEAGRASSES

plentiful on the central coast of Saudi Arabia; they monospecific prairies in the lower intertidal zone of

appeared at 1-2 rm depth as mixed vegetation in which muddy coasts. In the subtidal zone, pure stands of this Thalassia hemprichii constituted 60-70 percent of the seagrass were much denser, and the plants were plant cover, Cymodocea rotundata 20-30 percent and larger. Mixed stands of Halodule uninervis with Halodule uninervis 10-20 percent. Pure stands of Halophila stipulacea, and sometimes also Halophila

Halodule uninervis were common on this coast in ovalis, were common in the two gulfs as well'^'™'. Four

shallow water In very shallow lagoons, a thin-leaved other communities dominated by Halodule uninervis

form appears, whereas on open coasts, a little deeper, were reported from the Sinai coast of the Gulf of Elat: the beds are composed of the wide-leaved form. the Halodule uninervis-Syringodium isoetifolium

Cymodocea serrulata dominates in seagrass beds community, the Halodule uninervis-Syringodium between 0.5-2 m deep, mal

plant coven In the shallower beds 10.5-1 ml, it is Halodule uninervis-Cymodocea rotundata community accompanied by Halodule uninervis and Halophila and the Halodule uninervis-Halophila ovalis

avails and in the deeper beds (1-2 ml by Cymodocea community. Vegetation types dominated by Halophila

rotundata and Halodule uninervis. Small, 0.5-A m' in stipulacea occupy a wide range of habitats. Mostly

size, almost pure patches of Syringodium isoetifolium Halophila stipulacea is represented by rather dense occurred at one site along this coast at depths monospecific beds that extend between the lower

of 0.5-1 m. The green alga Caulerpa serrulata intertidal zone and depths of 50-70 m at the Gulf

accompanied the dominant seagrass in these patches. of Elat.

In another site, Syringodium isoetifolium was mixed Density in these beds decreases below 10 m"*'.

with Thalassia liemprichii, Cymodocea rotundata and Here and there mixed stands occur, in which Halophila

Halodule uninervis. Beds of Enhalus acoroides were stipulacea is accompanied by Halodule uninervis or

unusual on the central Saudi Arabian Red Sea coast. Halophila ovalis, and in one small patch near Zeit Bay

Pure patches, about 30 m' in size, grew at 1-2 m on IGhubbel ez-2eitl at the mouth of the Gulf of Suez, also

coarse sand with shell debris on top and black mud with Thalassodendron ciliatum''"'^°'. The Thalasso-

below, in one site on this coast. Halophila ov3(/s formed dendron ciliatum community is the most complex of

small patches, 0.5-2 m in diameter, of sparse growth in Red Sea seagrass communities, and probably the most

shallow water in most localities visited"". important for other life forms. The roomy space under

the seagrass canopy and between its woody vertical

Gulfs of Suez and Elat stems harbors larvae of many pelagic animals, as well

At the Gulf of Suez and the Gulf of Elat, in the north, as its own assemblage of sciaphilic plants and animals.

thin-leaved Halodule uninervis formed sparse The height of these vertical stems, varying with depth

Case Study 5.1 land the largest-leaved shoots) occurring ISRAELI COAST OF THE GULF OF from 18 to 25 m. The extent of the bed, as ELAT well as biomass within the bed, has been observed to fluctuate during the last few

Along the Israeli coast of the Gulf of Elat, at the years, with a general decline during the last

northwestern end of the gulf, Halophila stipulacea SIX years.

IS the only seagrass found at all sites but one (the Several sites are located near the navy base

middle of the site south of the Marine Laboratory, and the commercial harbor Plants grow at

where a small bed of Halodule uninervis is also depths from 8 to more than 25 m.

presentl. In 2001 the distribution of Halophila A further site is near the harbor where oil stipulacea was follows: and petrol are unloaded. Plants grow at 20- 30 m depth,

Along the northern shore of the Gulf of Elat. A substantial site extends from just south of An extensive bed of Halophila stipulacea the Steinitz llnteruniversityl Marine

occurs along the northern shore of the Gulf Laboratory to the Egyptian border Plants

of Elat, probably extending towards and grow at depths from 7 m to over 30 m.

beyond the nearby Jordanian town of Al' Between this and the site near the harbor,

Aqabah. The plants grow at depths from 5 m there are sporadically occurring smaller to more than 45 m, with the highest densities klOOm'j beds. The eastern Mediterranean and the Red Sea 71

from around 15-20 cm at the shallows to more than 1 m at 30 m depth, determines the volume of this under- canopy space.

Thalassodendron ciliatum is unique among Red

Sea seagrass communities in extending right up to coral reefs, without the usual "halo" zone that typically separates reefs from seagrass beds in their proximity.

This halo is formed by reef fishes grazing on the other seagrasses. Standing stocl< of the Thalassodendron ciliatum community is by far the highest among Red

Sea seagrass communities; its productivity, however, is among the lowest. This seeming contradiction stems from the extremely low consumption of most of the organic matter produced by the seagrass and by epiphytic algae in the under-canopy space. The only highly productive and quickly consumed element in this community is that of photophilic epiphytic algae of the Butterfly goby [Amblygobius albimaculatus] in seagrass in the Red upper, well-illuminated surface of the canopy, on which Sea, Jordan, many herbivorous fishes and invertebrates, mainly '''°'. snails, graze'" the Israeli Red Sea coast (only about 5 km long!

The Synngodium isoetifolium community is rare probably occupy some 0.5-1.0 km'. in the Gulf of Elat, where it forms small patches.

However, the plant accompanies other seagrasses in EFFECTS OF POLLUTION communities they dominate. Monospecific stands of Most of the few reports on pollution effects on seagrass sparse vegetation of Halophila avails usually appear in beds in the eastern Mediterranean and the Red Sea the Gulf of Elat as a narrow belt at the lee margins of refer to chemical pollution. Haritonidis ef a/."" in 1990 larger stands of Halophila stipulacea. or in clearings reported considerable declines in the sizes of beds of within wide beds of the latter Mixed stands of Halophila Posidonia oceanica and Cymodocea nodosa in the ovalis, Halophila stipulacea and Halodule uninervis Thermaikos Kolpos (northern Aegean Sea) during the appear in wider areas. Cymodocea rotundata beds are preceding two decades, with the former suffering the second least common seagrass community in the greatest losses. They also remarked that the density of

Gulf of Elat, forming monospecific dense stands down the shoots had decreased, and that marked changes in to 2 m. the seagrass epiphytic communities had taken place. Thalassia hemprichii, although the least common The authors attributed these phenomena to the seagrass on the Sinai coast of the Gulf of Elat, increased amounts of domestic and industrial dominates in four communities at the southern part of pollutants discharged into the gulf during that period. this coast. The first is represented by dense mono- In contrast, Zostera noltii, the least common of the specific beds growing on a layer, about 30 cm thicl<, of three seagrasses that occur in the gulf, seemed to have very coarse-grained substrate made of gravel-sized benefited from the increased discharge of sewage, as coral debris covering the underlying rock. Beds of the area covered by its beds had increased.

Thalassia hemprichii and Halophila stipulacea in equal A similar decline in the area occupied by proportions occurred on the same type of substrata, Posidonia oceanica beds, and their thinning, was but the unconsolidated layer was somewhat thicker. reported for Cyprus'"', but here the authors attributed

Wide areas of Thalassia hemprichii with Thalasso- these phenomena to competition with the invading dendron ciliatum appeared at Ras Muhammad, on the green alga Caulerpa racemosa. Between 1992 and tip of the Sinai Peninsula, to the seaward of mono- 1997, dense stands of the latter replaced Posidonia specific Thalassia hemprichii stands on a thin 20-cm oceanica in part of the area it had covered at the layer of even coarser unconsolidated material. Finally, beginning of this period (total plant cover in the large areas of dense vegetation of Thalassia Posidonia oceanica beds decreased from 70-90 hemprichii. with 20-40 percent Halodule uninervis, percent to AO-60 percent), and a number of algae, not covered large stretches of wide reef flats between previously found in the thinned beds, penetrated into

Marsa abu Zabad and Shorat el Manqata', growing on them, not replacing Caulerpa prolifera, an accom- coarse coralUgenous sand at 0-30 cm below the low panying species in some of the Posidonia oceanica water of spring tides'^". beds during the earlier period. Similarly, Fishelson ef

The total populations of Halophila stipulacea on a/."" reported that Halophila stipulacea meadows.

xr 72 WORLD ATLAS OF SEAGRASSES

formerly widespread, dramatically retreated at the AUTHORS

northern end of the Gulf of Elat, in the northern Red Yaacov Lipkin and Sven Beer. Department of Plant Sciences, Tel Aviv

Sea. Here the source of pollution was fish culture in University, Tel Aviv 69978, Israel, Tel: +972 1013 640 9848. Fax: +972 1013

cages in the gulf. 640 9380 E-mail: lipl(in0post tau.ac.il

Dando et a(."*' dealt with the effects of thermal

pollution. They reported that Cymodocea nodosa David Zakai, Israel Nature and Parks Protection Authonty, RO. Box 667,

replaced Posidonia oceanica near hydrothermal Elat 88105, Israel. The Interuniversity Institute for Marine Sciences, P.O.

discharge vents at the bottom of the Aegean Sea. Box469. Elat 88103. Israel.

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the Red Sea coast of Saudi Arabia, Aquatic Botany 7: 71 -78. 7A WORLD ATLAS OF SEAGRASSES

6 The seagrasses of THE ARABIAN GULF AND ARABIAN REGION

R.C. Phillips

The seagrass ecosystem of the Arabian Gulf and Manifah, in Al-Musallamiyah, south of Abu'Ali, in (hereafter called "the Gulf'l is a unique biotope. Tarut Bay'^', in the Dawhat Zalum (Halfmoon Bayl, parts

The Gulf is a shallow semi-enclosed sea of Al Uqayr and in the Gulf of Salwah'". Seagrass

'. measuring ca 1 000 km by 200-300 km" The average occurrence around Bahrain is extensive'"^'. Sheppard et

depth is only 35 m. The maximum depth of 100 m al."' stated that seagrasses were extensive along the

occurs near the entrance to the Strait of Hormuz. There coasts of , but failed to provide documentation or

are vast areas in some of the Gulf States, such as the maps. The seagrass occurrence in the UAE is also

United Arab Emirates lUAEl, Saudi Arabia and Bahrain, extensive"". An estimated seagrass occurrence of 5500

vi/ith shallow areas less than 15 m deep suitable for km' occurs in Abu Dhabi Emirate alone. seagrass growth. Jones'" stated that while the coastline of Iran was

Seagrass habitats have been designated a critical mainly rocky, the western and southern coastlines of

marine resource in the Gulf" ". They have also been the Gulf were soft sediments. It also appears that the

listed as a key renewable resource'' ". Gulf has its most extensive shallow flats on the western

There are only three species of seagrass in the and southern coastlines. From an analysis of the

Gulf. It is considered to be a very stressful habitat for largest seagrass beds within the Gulf, the beds

seagrasses"', characterized by large seasonal air and increase in size as one proceeds eastward along the water temperature variations, fluctuating nutrient southern shoreline.

levels and high salinities. The three species found are

considered to be tolerant of such conditions (Table 6.11. BIOGEOGRAPHY

Outside the Gulf, as many as 1 1 seagrass species have The Arabian Gulf is characterized by large seasonal

been described for the Red Sea area""'. Seven species temperature variations. The area is and and very hot for

are known in the , seven species in the many months of the year. There are few rivers that "'" Gulf of Aqaba"- and eight in the Gulf of Suez'". drain into the Gulf. There is little rainfall and very little

Jones'" observed that seagrasses occur at only freshwater runoff. In addition, the evaporation from

SIX locations in Iran. He stated that the Iranian coastline Gulf waters leads to salinities averaging 40 psu, but

was mainly rocky. No seagrasses have been reported which exceed 70 psu in the Gulf of Salwah'". Price and

for Iraq. Seagrass occurrence in Kuwait is quite Coles"" reported that inshore waters of the Gulf vary

sparse"". Jones'" stated that Haloduie uninervis was seasonally in temperature from 10°C to 39°C and

the principal species in Kuwait and reported that large offshore from 19°C to 33°C, with salinities varying from

beds of seagrasses extended along the coasts of Saudi 38 psu to 70 psu. The three species which are found in Arabia. However, lUCN-The World Conservation the Gulf can tolerate these extreme conditions: Union'" diagrammed seagrasses along the entire Gulf Haloduie uninervis. Halophila ovalis and Halophita

coastline occurring in scattered locations. As a whole, stipulacea.

the resulting report stated that seagrasses were of only Very few studies on seagrasses in the Gulf have limited occurrence along the Saudi Arabian coast. been produced reporting density, biomass and primary

Price"" sampled at 53 sites along the entire coastline production values. Basson e( al.'" calculated the aver-

and found seagrasses at only 15 sites. The largest beds age dry weight of seagrass leaves in Tarut Bay (Saudi

of seagrass occurred in the north between Safaniyah Arabial to be 128 g/m'. They doubled this value for an

\\ The Arabian Gulf and Arabian region 75

annual average. They calculated the energy content of the 175-knn' seagrass bed in the bay to be ].Ax 10" kcal, k

an energy equivalent of about 95000 barrels of oil.

Price and Coles"" took samples from a series of IRAQ sites along the entire Gulf coast of Saudi Arabia. They IRAN took triplicate samples at eight stations during four KUWAIT*' ' IRABUt seasons in 1985 and three seasons in 1986. Seagrass , K,„„l yovir biomass values ranged from 6.0 to ^35 g dry weight/m'

AJ- ^usallamiyah-*. ' ;;„-,„ B„, _^ , Imeans for each station ranged from 53.3 to 23^.8 Ad Dan -^,. « 3^„|„|^ I Jubail Alanne -----— ^^ i^ -25 ^ g/m'l. They reported significant correlations between Wildlfte S. AIAziziyah,-y. ! QATAR . //..™"-- seagrass biomass and depth, sediment hydrocarbons AlUqayr-''^ //• ^_ Jfcj^Abu Dhabi .... and sediment grain size, but no significant correlations FashlAdhm | ^^ Oul/ofSalwah • between biomass and season, salinity, or nutrient concentrations and heavy metals. SAUDI ARABIA ^ Kenworthy et al.'"" reported total biomass of OMAN Halodule uninervis from two heavily oiled sites at Ad Dafi and Al-Musallamiyah (northern Saudi Arabia),

ranging from 50 to 116 g dry weight/m^ At one non- K *

15° ^ Table 6.1 \ YEMEN Seagrass species in ttie Arabian reg on \ 100 200 300 400 500 KilomelefS

Arabian Gulf Number of species Species i » 45- Iran 1 Halodule uninen/is E 55- E

Iraq No seagrass Map 6.1

Kuwait 2 Halodule uninervis Tfie Arabian Gulf and Arabian region

Halophila ovalis

Saudi Arabia 3 Halodule uninervis oiled outer bay site nearby, the biomass was 188 g dry

Halophila ovalis weight/m'. For Haloptiila ovalis. the lowest values were

Halophila stipulacea observed in the oiled inner bay stations 112 and 17 g dry

Bafirain 3 Halodule uninenis weight/m^l, while the largest biomass was found in the

Halophila ovalis non-oiled outer bay site (39 g dry weight/m^l. The

Halophila stipulacea biomass of Halophila ovalis was nearly three times

Qatar 3 Halodule uninervis greater at another heavily oiled site (Jinnah Island! as

Halophila ovalis compared to an unoiled site (TanequibI 13^ compared

Halophila stipulacea with 12 g dry weight/m'l. Densities of Halodule

United Arab 3 Halodule uninen/is uninervis Mav\ed from a high of 5879 shoots/m' at oiled

Emirates Halophila ovalis inner bay and mid-bay stations at Dawhat Al-

Halophila stipulacea Musallamiyah to the lowest densities recorded for oiled

inner bay and mid-bay sites at Dawhat Ad Dafi (1 960 to

Arabian Sea Number of species Species 3250 shoots/m'|. Densities for Halophila ovalis at

Oman 4 Halodule uninen/is heavily oiled inner and mid-bay sites at Dawhat Al-

Halophila ovalis Musallamiyah and Dawhat Ad Dafi ranged between

Syringodium isoetifolium 1 530 and 2533 leaf pairs/m'. A similar range of values

Thalassodendron ciliatum existed for Halophila stipulacea. At oiled sites at

Yemen 7 Cymodocea serrulata Tanequib and Jinnah Island, densities ranged from

Enhalus acoroides 1 721 to 3 776 leaf pairs/m^ for Halophila ovalis, with a

Halodule uninen/is single value of 2 772 leaf pairs/m^ for Halophila

Halophila ovalis stipulacea at Tanequib. This study was conducted in

Syringodium isoetifolium 1991, one year after the Gulf War oil spill.

Thalassia hempnchii In Tarut Bay, Basson ef al"' derived tentative

Thalassodendron ciliatum productivity values by converting from biomass values

of seagrass leaves. They estimated the production 76 WORLD ATLAS OF SEAGRASSES

value of the leaves to be 100 g carbon/m'Vyear. These productivity of Halodule uninervis at a single oiled calculations did not include the productivity of roots and station at Dawhat Ad Dafi. Values ranged from 0.09/i to

rhizomes. These values included many assumptions 0.250 g dry weight/mVyear

and were largely hypothetical'^'. Durako ef a(.''" exposed plants of all three species Kenworthy et al"°' determined the net leaf from a vi/ell-flushed area seavi/ard of the south of

Case Study 6.1 THE BAHRAIN CONSERVANCY

In the summer of 1982, civil engineers won a than 100 m away Of greater concern were the

contract to build a roadway from Saudi Arabia more obvious physical impacts of dredging and across 25 km of sea to the island state of reclamation. The water became more turbid the

Bahrain'"'. The causeway, consisting of five bridges closer the team moved to the construction work.

linked by seven solid embankments, carries two Long plumes of sediment stretched downstream

parallel roads from Jasrah on the northeast coast from the construction areas. Just to the north of

of Bahrain, across Umm Nasan Island, over the the causeway, it found a layer of very fine silt mud

Gulf of Bahrain to join the Saudi coastline at At 20 cm thick, with a complete absence of surface

Aziziyah. The largest of the bridges weighs 1 200 flora and fauna, but a high abundance of infaunal

metric tons, and passes 28.5 m above the water It polychaete worms dominated by Ceratonereis.

can carry 3000 vehicles per hour. Halfway between Below the silt was a once healthy bed of seagrass,

Umm Na'san and Al Aziziyah, an artificial island now almost completely dead. This was probably was built to house coastguards, customs and once a part of a large nursery of shrimp within the

immigration offices Madany et a/."" stated that the bay area, as large numbers of juveniles and fish

total cost of the project was US$564 million, and thrived in the nearby intertidal flats. These flats

was one of the largest projects undertaken in the also supported a rich fauna, including crabs and during the 1980s. mollusks. At two sites south of the causeway on

At least half of the causeways span consists the west coast of Bahrain there was no clear

of embankments of dredged rocks and fine mud evidence of damage.

spoil. In consideration of the massive negative

impacts which this project could have on the SYMPTOMS OF STRESS

extensive seagrass beds of Bahrain, the Regional At the offshore sites on the east coast, where

Organization for the Protection of the Marine relatively unspoiled conditions were expected, the

Environment from Pollution IROPMEI arranged to team instead found turbid water On calm days,

cooperate with Bahrain's Directorate of visibility was only 60 cm into the water, and a layer

Environmental Affairs to carry out an ecological of fine silt covered the seabed out to the coral study on the possible effects of building the reefs. These reefs were already displaying the causeway, A team from the Tropical Marine classic symptoms of sedimentary stress, with

Research Unit at the University of York carried out horizontal faces showing bleached skeletons the study through lUCN and the United Nations devoid of polyps. The round heads of Platygyra

Environment Programme lUNEP) looked like a monk's head with a tonsured haircut, with the top bleached white. Dead and dying SAMPLING THE SITES branches of were covered with sea

Sampling was done in three visits in 1983, each of urchins or were turned green by colonies of about one month. Flora and fauna, and epiphytic algae.

temperature, salinity, turbidity and chlorophyll Madany et a/.'^" did not state whether this

concentrations, and were sampled at project was regulated by the Environmental

SIX coastal and six offshore sites. Protection Committee of Bahrain. This committee

Many of the sites sampled were deemed to has established specific rules and regulations to

be critical habitats. In the immediate vicinity of the control dredging and reclamation projects before causeway between Umm Na'san and the main implementation. However, the authors found that island of Bahrain, the water was found to be 9 psu some projects were carried out without the

more saline in the now partly enclosed bay on the permission of the committee, due to the lack of

south side of the road than just to the north, less legislation to support the regulations. The Arabian Gulf and Arabian region 77

Dawhat Al-Musallamiyah, Saudi Arabia, to un- faunal species associated with the seagrass beds in weathered Kuwait crude oil. The treatment duration Tarut Bay, an area of -ilO km'. McCain'"" found 369 was 12 to 18 hours. There were no significant species of benthic organisms in the seagrass beds on photosynthesis as against irradiance response effects, the Saudi Arabian coast between Manifah and Bandar nor were there any effects noted on rates. Mishab.

Their conclusion was that the Gulf War oil spill The major associated animal species of the primarily impacted intertidal communities, rather than seagrass beds of the Gulf are dugongs, green sea the submerged plant communities of the northern Gulf turtles, oysters and shrimp" ^ '^ ' ' '". Jones'" region. stated that the collapse of the shrimp fishery in the

Phillips et al."" found density values of Haloduie northern Gulf has been largely attributed to the loss of

uninervis from five sites in the UAE to vary from 1 7A5 to the critical seagrass habitat.

21 590 shoots/m^ while leaf pair densities of Haiophila The preliminary studies done by Basson ef al"' avails from two sites varied from 166 to 1 108/m'. suggested that the annual production of the Tarut Bay

Outside the Gulf, Wahbeh''*' and Jones et al.'"', seagrass beds may be about 230 million kg wet weight using oxygen release methods, estimated values of per year This, in turn, might be expected to yield 2.3

1 326 g carbon/mVyear for Haloduie uninervis in the million kg of fish, at a value of US$8 million annually, or Gulf of Aqaba, 617 g carbon/mVyear for Haiophila the same quantity of shrimps at a value of US$12 stipulacea and 11 g carbon/mVyear for Haiophila million per year [conversion rate of 1 percent efficiency ovali^". for use of seagrass for fish and shrimps].

The studies of Basson ef al."' and Price ef a/.'"' lUCN'" estimated that the industrial shrimp suggested that primary production from seagrass and fishery in the Saudi Arabian Gulf and the Red Sea shallow water benthic algae may be of greater totaled some 6 800 metric tons, with a value of importance in the Gulf than that from phytoplankton. US$35.28 million. The net profit was US$13.9<1 million, Coles and McCain'"' identified a total of 83i an increase of US$^.78 million from 1982. The lUCN species associated with seagrass and sand/silt report concluded that this economic value of the Saudi substrates at seagrass stations north of Al Aziziyah Arabian fisheries would be maintained and increased,

ISaudi Arabia). Mean numbers of benthic organisms in but only if managed on a sustainable basis. It also noted the seagrass beds averaged nearly 52 000/m', an that shrimp production had dropped over the five years average of 36000/m' in the Manifah-Safaniyah area'"'" previous to the date of the report. This was the result of and up to around 67 000/m" in Tarut Bay either the resource being overexploited, or a

Basson et al"' reported a total of 530 floral and destruction of the critical seagrass habitat, or both.

Case Study 6.2 RAPID ASSESSMENT TECHNIQUE

Price"" devised a simple, rapid assessment individuals for fauna, both within each sample technique for coastal zone management area of the quadrat. Cluster analysis was applied requirements The method was based on semi- after the scores were recorded. The method quantitative Irankedl data on coastal resources, chosen for analyzing the biological resource data uses and environmental impacts. He recorded and the resource uses/impacts was the Bray-

data at 53 geographically discrete sites, at Curtis similarity Index, followed by a hierarchical

Intervals of usually less than 10 km along virtually clustering of sites, using the arithmetically the entire 450-km Saudi Arabian Gulf shoreline. determined centrold. The results of the cluster

Each sampled site comprised a quadrat 500 m x analyses were depicted as dendrograms. 500 m, bisecting the beach Within each quadrat, Correlations were determined between, and the abundance or magnitude of the mangroves, within, the following groups of variables: biological seagrasses, halophytes, algae and freshwater resources and latitude/salinity; and biological vegetation were estimated and recorded semi- resources and uses/environmental impacts. quantitatlvely. The attributes were scored using a Price"" concluded that the method can be of value

ranked scale of 0-6 10 was no impact; 6 was the to managers and scientists alike, to determine greatest impact). For the resources, abundance associations between different environmental

scores were based on estimates of areal extent variables, and is especially useful for

(m^l for flora, or of estimated number of management. 78 WORLD ATLAS OF SEAGRASSES

widespread around the islands, covering most of the east coast, from south of Fasht Adhm to the . Seagrasses also covered significant areas around Fasht Jarim and along the west coast, south and north of the Saudi-Bahrain causeway and along the southwestern coast. He also reported that the seagrass

beds died back to low cover in winter, but found the

beds to be healthy in March 1986. He concluded that the

majority of well-developed beds occurred to the

southeast of Bahrain. Halodule uninervis was the most

common species. In summer, Halodule uninervis cover was as high as 90 percent. More than 50 percent of the sites at which seagrasses occurred supported 40 percent or greater cover

In the UAE, Phillips et a(."*' performed an extensive study of seagrass distribution and extent of

growth in 1999 and 2000. Halodule uninervis was the

Dugong feeding on seagrasses. most abundant species in the Gulf waters of the UAE. Seagrasses occurred from 1.5 m to 15 m deep. Even

Vousden'*' linked the extensive seagrass beds though Ha/odu/e un/nerv/s was occasionally found at 15

surrounding Bahrain to juvenile stages of commercially m deep, Halophila ovalis tended to become the important penaeid shrimp and to a number of adult fish dominant species in depths greater than 11 m.

species, e.g. Siganus spp., a popular local food Extensive continuous meadows were found wherever resource. Seagrasses also provided a habitat for the water depths were suitable Ifor Halodule uninervis

settlement of high densities of pearl oyster spat from 1 .5 m to 1 1 m deep). Digitized estimates show that

[Pinctada sp.), an important commercial species in there were 5 500 km' of seagrasses in the Gulf waters Bahrain. Vousden'^' reported a herd of 700 dugongs at of Abu Dhabi Emirate.

one location over seagrass beds in Bahrain. PRESENT THREATS AND LOSSES

HISTORICAL AND PRESENT DISTRIBUTION Sheppard ef a(''' listed a variety of coastal and marine Jones'" stated that seagrasses were sometimes present uses and their major environmental impacts which

in the upper subtidal zone 12-3 m deep) along the Saudi affect or could affect seagrasses in the Gulf. They Arabian coast as a band some 1-20 m wide. In these ranked them as short-term to medium-term impacts, situations, seagrasses were recorded at 57 percent of medium-term to long-term impacts, and possible

the shore sites inspected, but seldom in luxuriant longer-term impacts. stands. The report estimated an areal extent of sea- Except for my own observation on the effects of oil grasses along Saudi Arabia of 370 km". De Clerck and globules and oily black films over the bottom near an oil

Coppejans'^" studied seagrass distribution in the Gulf processing plant west of Jabel Dannah (seagrasses sanctuary between Ras az-Zaur and the northeast point absent under the films], none of the literature records

of Abu All. They found that Halodute uninervis formed any negative impacts from oil-related pollution in the extensive meadows from the low-water mark to 3 m Gulf,

deep. Locally, it was replaced by Hatophila avails and Vousden'^' stated that the agricultural industry

Halophila stipulacea. In some places near Dawhat Ad was one of the major sources of organic non-

Dafi, seagrass cover declined rapidly below 3 m deep. petrochemical pollution to the marine environment. He At the Jubail Marine Wildlife Sanctuary ISaudi found that the agricultural sector contributed 50 Arabia), Richmond'"' found that Hatodule uninervis was percent of the total biological oxygen demand (BOD) again the dominant species, with the best developed loading to the waters around Bahrain. An oil refinery beds at Z-A m deep. Both species of Halophila were discharged 19 percent of the loading, with domestic also found. Seagrasses were not found below 5 m. discharges amounting to some 25 percent. The Vousden'^' mapped the seagrasses of Bahrain remaining discharges came from other industries.

using satellite imagery. He reported that, as far as Sheppard et ai'" stated that coastal reclamation percentage cover was concerned, seagrass beds were and dredging represented one of the most significant the major soft-bottom habitat type within the 2-12 m impacts on the coastal and marine environments of subtidal zone. He found areas where the seagrasses the Arabian region. They reported that coastal went to H m deep. Seagrass distribution was development and infilling have been far greater along The Arabian Gulf and Arabian region 79

Case Study 6.3 MARINE TURTLES AND DUGONGS IN THE ARABIAN SEAGRASS PASTURES

The seagrass beds in the Gulf are home to the worlds incubation'™' Adults can reach over 1 m in length second largest assemblage of endangered dugongs and weigh over 150 kilograms, and feed nearly [Dugong dugon] - upwards of 7000 individuals'" (the exclusively on seagrasses. The Gulf green turtles largest population is off the coast of Australia), exhibit strong nesting site fidelity, returning to the distributed mostly in the southern and southwestern same beaches to nest within and over several regions of the Gulf. The dugongs belong to the seasons'^'. This fidelity coupled with a relatively low monotypic order Sirenia and are the only herbivorous emigration rate from the Gulf, other than to the marine mammals, feeding directly on seagrasses. Omani nesting site, suggests that populations which

They can live to be 70 years of age and grow to over 3 nest and feed within the Gulf are. much as the m in length and 400 kg in weight. Their nearest living dugongs. genetically and physically isolated. non-sirenian relative is believed to be the elephant. Threats to the turtle populations in the Gulf Dugongs have extremely low reproductive capacities include moderate egg and adult harvesting, as they do not become sexually mature until about ten mortality in commercial and artisanal fishing gears, years of age. with subsequent calving only occurring loss of nesting habitats, and significant loss or at intervals of seven or more years. alteration of foraging grounds. While most Gulf- The most important foraging habitats for bordering nationals do not generally eat turtles or dugongs in the Gulf are on either side of Bahrain, off their eggs, many fishing boat crews are being

Saudi Arabia between Qatar and the UAE, and off Abu replaced with a number of other nationalities who

Dhabi"'. Outside the Gulf, the nearest population is in do, and unless the nesting beaches are patrolled the the Gulf of Kutch. northern India, suggesting the Gulf fishermen frequently dig up clutches of eggs. population IS genetically and physically isolated. Until Fishermen are also known to take adults on an some 30 years ago. dugongs formed the staple diet of opportunistic basis"". An important modern impact many Gulf-bordering villages, and had been used for IS the extensive dredging and landfilling projects of their leathery skin and fats rendered into oils'". This several Gulf-bordering nations, which are altering or suggests that populations were significantly larger completely destroying foraging IseagrassI pastures. than at present, and further reduction in population As in the case of the dugongs. the seagrasses upon size might adversely impact their chances of survival which the green turtles in the Gulf depend are of supreme importance to the survival of these FEEDING GROUNDS isolated, regionally important populations. Significant populations of herbivorous green turtles

[Chelonia mydas] also depend on the seagrasses of CALL FOR PROTECTION the Gulf. They nest on Karan and Jana Islands off the Based on the genetic isolation and population sizes

Saudi Arabian coast lea 1 000 females/yearP", of these two species, a recent meeting of experts in outside the Gulf at Ras Al-Hadd, Oman lea 4000 Hanoi. Viet Nam. concluded that the Gulf seagrass females/yearl'^*', and to a smaller extent off the habitats are of outstanding universal value at a southern coast of Iran, and are believed to feed global level, and recommended they should be among the seagrass pastures bordering the protected through international instruments such as southern Gulf. Evidence of this is supported by re- the World Heritage Convention. Although there are a cent tag returns from Saudi Arabia and Oman'^''^". number of national conservation programmes and

The green turtles in the Gulf also have low repro- regional initiatives, they tend to be species-specific ductive capacities, with estimates of sexual and not. as yet, directed at preserving marine habi- maturation periods of IS-AO years, and a survival tats other than coral reefs. There is a need for rate of hatchlings of roughly only one in a thousand. focused attention on the remaining habitats, par-

These turtles have several key physiological features ticularly seagrass pastures, if the populations of that set them apart from other Testudines. such as dugongs and green turtles are to survive. non-retractile limbs, extensively roofed skulls, limbs converted to paddle-like flippers, and salt glands to Nicolas J Pilcher excrete excess salt. As with other reptiles, the sex of Community Conservation Network, P.O. Box W17, Koror, Republic of hatchlings is dependent on temperature during Patau 80 WORLD ATLAS OF SEAGRASSES

throughout the Gulf States. However, no one has documented the amount of historical loss of

seagrasses as a result of this activity. Such studies are

needed. The study of Phillips et al™' in the UAE appears to be the only study that has precisely

documented the extent of seagrass distribution in any

of the Gulf States. Such studies are also needed.

POLICY AND IvJANAGEMENT Each Gulf State has a varying number of authorities

designed to study and/or protect seagrasses. However,

one can still see massive and continuing dredging and

land reclamation in all countries. Since there is so little

effective cooperation between the states as concerns marine conservation of seagrasses, the feeling within

the Gulf IS that this conservation and protection effort

haioauie uninen'is, adu unaDi area would be best accomplished at the regional level. There

is a plan, the Kuwait Action Plan IKAPI, based on the

the Gulf coast than In the Red Sea or other parts of the Kuwait Regional Convention for Cooperation on the Arabian region'". Protection of the fvlarine Environment from Pollution. lUCN"' and Sheppard and Price™ reported that All countries within the KAP region are signatories of approximately AO percent of the Saudi Arabian coast the convention. lUCN/UNEP'" reported that the priority had been developed, involving extensive infilling and concern was the current extensive loss or severe degra-

reclamation. They found that conditions were similar in dation of seagrass habitats, and the probable reduction

other Gulf States, such as Bahrain and Kuwait. I^ore in natural resources associated with this habitat. than 30 km^ 13306 ha) of Bahrain was either reclaimed The reports of Price'", the Coral Reef and Tropical

or artificial land'^". In the late 1980s, there were plans Marine Research Unit'"' and Price et a/.'^" contained

for further infilling on an area of almost 200 km' in detailed recommendations for conserving seagrass

Bahrain'"'. 1 have observed extensive dredging beds in the Gulf area. These focused largely on

activities around the UAE. These activities involved preventing further uncontrolled habitat destruction and maintenance channel dredging, dredging for new widespread pollution. lUCN/UNEP'" concluded that any channels and land reclamation. They were being legislation aimed at preventing impacts must be

carried out inshore in the most extensive continuous followed by enforcement. Little has been done to

seagrass beds in Abu Dhabi Emirate. implement these recommendations. Except for the

Price'" noted that dredging and coastal infilling UAE, none of the countries has taken any steps to

projects were occurring throughout Saudi Arabia, e.g. implement the beginning of an effective management

Tarut Bay and the Jubail area, and also in Bahrain and program that would start with baseline mapping, Kuwait. He conjectured that such activity was likely to followed by periodic monitoring and mapping efforts. affect not only the shrimp and fish stocks, but also the The distribution and rate of seagrass loss needs to be

ecology of coastal habitats generally. determined in the various KAP countries. As of 1985, Vousden''' stated that the effects of coastal the conservation status of seagrass habitats had been

development represented a significant problem to the considered in Bahrain'""' and Saudi Arabia'^ "', but not in

marine environment of Bahrain. He noted that the detail in any of the other KAP countries.

shallow intertidal flats next to a reclamation site Sheppard ef al"' stated that in addition to the

became smothered in a thick glutinous silt often many UNEP Regional Seas Programme, there were other

centimeters deep and of little biological value due to its regional agreements, including those of the GCC IGulf anoxic nature. Offshore, the benthic communities Cooperative Council), the GAOCI^AO IGult Area Oil became choked by the anoxic sediments. Primary Companies fvtutual Aid Organisation) and others. These productivity was reduced drastically by the high agreements relate to environmental management and

sediment loads and consequent increase in water pollution control.

. Price et a/.'''' noted that seagrass had

become smothered as a result of the sedimentation AUTHOR

caused by dredging. Ronald C. Phillips, Florida (Marine Research Institute, 100 Eigfith

Thus, many studies have recorded the large-scale Avenue, S.E., St Petersburg, Flonda 33701, USA. Tel Ihomejt +38 101 692

and continuing dredging and land reclamation projects 413086. E-mail: ronphillips67raiiotmail.com ^1 1

The Arabian Gulf and Arabian region 81

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1 lUCN/UNEP (1985], The Management and Conservation of [1993], Assessment of the toxicity of Kuwait crude oil on the

Renewable Marine Resources in the Indian Ocean Region in the photosynthesis and respiration of seagrasses of the northern Gull.

Kuwait Action Plan Region. UNEP Regional Seas Reports and Marine Pollution Bulletin 27: 223-227,

Studies No. 63. 63 pp. 22 Wahbeh Ml [19801, Studies on the Ecology and Productivity of the

2 Sheppard CRC, Price ARC, Roberts C [19921. Marine Ecology of the Seagrass Halophila stipulacea. and Some Associated Organisms in

Arabian Region. Academic Press, London. 359 pp. the Gulf of Aqaba [Jordan], D Phil, thesis. University of York, 3 Basson PW, Burchard JE, Hardy JT, Price ARG [19771, Biotopes of 23 Jones DA, Ghamrawy M, Wahbeh MU [1987], Littoral and shallow

ttie Western Arabian Gulf. Aramco, Dhahran, 284 pp. subtidal environments. In: Edwards A, Head SM [edsl Red Sea. 4 Jones DA [19851. The biological characteristics of the marine Pergamon Press. Oxford, pp 169-193,

habitats found within the ROPME Sea Area. Proceedings of ROPME 24 Price ARG, Vousden DHP, Ormond REG [19831, Ecological Study of

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5 Vousden DHP [1988] The Bahrain Marine Habitat Survey, Vol, 1, under Construction, lUCN Report to the UNEP Regional Seas

The Technical Report, ROPME, 103 pp, Programme, Geneva,

6 Price ARG [1 982], Conservation and Sustainable Use of Natural 25 Coles SL, McCain JC [1990], Environmental factors affecting

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Meeting of the Gulf Coordinating Council to review environmental Environmental Research 29: 289-315,

issues. 26 McCain JC 11984]. Marine ecology of Saudi Arabia, The nearshore.

7 Price ARG, Chiffings TW. Atkinson MJ, Wrathall TJ [1987]. soft bottom benthic communities of the northern area, Arabian

Appraisal of resources in the Saudi Arabian Gulf. In: Gulf, Saudi Arabia, Fauna of Saudi Arabia 6: 102-126,

Magoon OT. Converse H, Miner D, Tobin LT, Clark D, Domurat G 27 Vousden DHP. Price ARG 11985], Bridge over fragile waters. New [edsl 5th Symposium on Coastal and Ocean Management. Scien(/s(No, 1451:33-35.

Vol. I. American Society of Coastal Engineers, New York, pp 1031- 28 De Clerck 0. Coppeians E [1994], The marine algae of the Gulf

1045. Sanctuary, In: Establishment of a Marine Habitat and Wildlile

8 Vine PJ [19861. in Arabian Waters. Immel Publishing, Sanctuary for the Gulf Region, Final Report for Phase III, Jubail and

London. 59 pp. Frankfurt, CEC/NCWCD, pp 254-280,

9 Preen A [1989], The Status and Conservation of Ougongs in the 29 Richmond MD [1996], Status of subtidal biotopes of the Jubail

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Series Report No, 10, Meteorological and Environmental Protection communities. In: Krupp F. Abuzmada AH, Mader lA [edsl A Marine

Administration, Jeddah, 200 pp. Wildlife Sanctuary for the Arabian Gulf. Environmental Research

10 Jupp BP, Durako MJ, Kenworthy WJ, Thayer GW, Schillak L [1996], and Conservation Following the 1991 Gulf War Oil Spill. NCWCO.

Distribution, abundance and species composition of seagrasses at Riyadh and Seneckenberg Research Institute. Frankfurt

several sites in Oman Aquatic 8o(any53: 199-213, 30 Sheppard CRC, Price ARG [1991], Will marine life survive in the

1 Lipkin Y [1977], Seagrass vegetation of Sinai and Israel. In: McRoy Gulf NewSaen(/s( 1759: 36-40,

CP, Helffench C [edsl Seagrass fcosysfems; A Scientific 31 Madany IM, All SM, Akter MS [19871, The impact of dredging and

Perspective. Marcel Dekker, New York, pp 263-293. reclamation in Bahrain. Journal of Shoreline Management^:

12 Aleem AA [1979], A contribution to the study of seagrasses along 255-268.

the Red Sea coast of Saudi Arabia, Aquatic Botany 7: 71-78, 32 Linden et al. [19901. State of the Marine Environment in the ROPME

13 Hulings NC [1979], The ecology, biometry, and biomass of the Sea Area. UNEP Regional Seas Reports and Studies, No, 1 1 2, Rev,

seagrass Halophila stipulacea along the Jordanian coast of the Gulf 1. UNEP, Nairobi,

of Aqaba, Botanica Marina 22: 425-430. 33 TMRU [1982] Management Requirements for Natural Habitats and

14 Jacobs RPWM. Dicks B [1985], Seagrasses in the Zeit Bay and at Biological Resources on the Arabian Gull Coast of Saudi Arabia,

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15 Hulings NC. Kirkman H [1982], Further observations and data on Research Unit. University of York.

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Gulf of Aqaba, Tet/iys 10: 218-220, mydas in the Arabian Gulf. Chelonian Conservation & Biology 3:

16 Jones DA [2002], Personal communication, 730-734.

17 Price ARG [1990], Rapid assessment of coastal zone management 35 Ross JP and Barwani MA [19821. Review of sea turtles in the

requirements: Case study in the Arabian Gulf, Ocean and Shorebne Arabian Area. In: Bjorndal KA [edl Biology and Conservation of Sea

Management 13: 1-19, Turtles. Smithsonian Institution Press, Washington, DC. pp 373-382. 18 Phillips RC. Loughland RA, Youssef A [Submitted manuscript], 36 Al-Ghais. Personal communication.

Seagrasses of Abu Dhabi Emirate. United Arab Emirates. Arabian 37 As-Saady Personal communication

Gulf, Tribulus. 38 Miller JO [19851, Embryology of marine turtles. In: Gans C, Billett F

19 Price ARG. Coles SL [1 992], Aspects of seagrass ecology along the and Maderson PEA [edsl Biology of the Reptilia, Vol. 1 4, John Wiley western Arabian Gulf coast, Hydrob/o/ogia 234: 129-141, & Sons, pp 269-328.

20 Kenworthy WJ, Durako MJ, Fatemy SMR, Valavi H, Thayer GVI/ 39 Miller JD [19891, Marine Turtles. Volume 1: An Assessment of the

[1993], Ecology of seagrasses in northeastern Saudi Arabia one Conservation Status of Marine Turtles in the Kingdom of Saudi

year after the Gulf \Nar oil spill. Marine Pollution Bulletin 27: Arabia, Coastal and Marine Management Series Report No, 9,

213-222, MEPA, Jeddah. 289 pp. 82 WORLD ATLAS OF SEAGRASSES

7 The seagrasses of KENYA AND TANZANIA

C.A. Ochieng

P.L.A. Erftemeijer

Seagrasses are a major component of the rich and in creeks and small rivers inside the productive coastal and marine ecosystems in the mangroves, where the water is very clear and the

East African region. The Kenyan (600 km| and bottom IS covered in a luxuriant growth of seagrasses.

Tanzanian 1800 km) coastlines have a shallow and In the delta areas of major rivers, such as the Tana

relatively narrow continental shelf bordering the Indian River in Kenya and the Rufiji River in Tanzania,

Ocean and are characterized by extensive fringing coral seagrass growth is minimal. reefs, several sheltered bays and creeks, limestone

cliffs, mangrove forests, sand and beaches"^'. BIOGEOGRAPHY

The tidal amplitude is rather large - up to ^ m near The following 12 seagrass species have been

l^ombasa'" - and therefore there is a fairly extensive encountered during several studies in Kenya and intertidal zone between the fringing reefs and the coast Tanzania"'": Halodule uninervis, Halodule wrightii,

in many places. The substrate in this zone consists Syringodium isoetifolium, Cymodocea rotundata,

mainly of carbonate derived from eroding reefs. Cymodocea serrutata, Thalassodendron ciiiatum,

The productivity of these intertidal areas is determined Zostera capensis, Enhalus acoroides, Halophila minor, predominantly by the presence of seagrasses and Halophila ovalis, Halophila stipulacea and Thalassia macroalgae, which grow wherever shallow depressions hempnchii. All species appear to be widely distributed

retain a covering of water during low tide. along the entire coastline of both countries, even those

The most extensive seagrass meadows occur in with only a limited number of observations, such as back-reef lagoons, which are found between the Zostera capensis, Halophila minor and Halophila

beaches or cliffs and the adjacent fringing reefs. stipulacea. Seagrasses often occur in mixed Narrow channels connect the lagoons with the sea communities consisting of two to several of the 12

during low tide, but high-tide waters pass over the reef species. Thalassodendron ciliatum is often the most crest into the lagoon. Apart from many fish species that dominant species, forming pure stands with high reside permanently inside such lagoons, many other biomass. Three additional seagrass species {Halodule

species feed there during high tide, leaving for deeper pinifolia. Halophila ovata and Halophila beccarii] have

offshore waters during the ebbing tides. been reported for the region" '^', but these observations At several places along the East African coast, may constitute misidentifications and need further these lagoons grade into sheltered semi-enclosed bays confirmation.

le.g. at Mida, Kilifi, Mtwapa, Tudor, Gazi and Funzi in There is some controversy over the occurrence of

Kenya, and at Tanga, Bagamoyo, Mohoro, Kilwa and the species Halodule wrightii in East Africa. Most

Mtwara in Tanzania! where mangroves, seagrass authors have included Halodule wrightii in their species

meadows and coral reefs occur as adjacent and descriptions for the region based on leaf width and tip

interrelated ecosystems. Where the supply of morphology" °'. However, field observations in Florida""

terrigenous sediments is limited, seagrass vegetation indicated that leaf tips in Halodule spp. vary widely from

is also common in the creeks and channels that run bicuspidate to tridentate on shoots of the same through the mangroves, possibly functioning as traps rhizome. Experimental culture"" revealed that leaf tips

and reducing the extent of the fluxes of particulate of Halodule are environmentally variable, related to matter and nutrients between the mangroves and the nutrient variability or tidal zone. Furthermore, isozyme

ocean. In Gazi Bay IKenyal, for example, it is possible to analyses of diverse collections throughout the tropical Kenya and Tanzania 83

Seagrass beds in the region also support sizeable

populations of two endangered species, i.e. the green

turtle Chelonia mydasl^°'^'" and the dugong Dugong Lamu Island Mambrul dugon'"^'^^', both of which feed on seagrasses. In 199^, Malindi \^ lormi :t Buy a total of iA3 sea turtles was recorded along the Mida Creek ^ i» •" * - Watamu Marine Kenyan coast, among which the green turtle was by far National Park Kiijfi • species'"'. In Tanzania, there are no Mombasa^ Bambun 4' the most common Manne GiEi Bay Mombasa National recent population studies"". Similar surveys along the Park and Reserve Funzi/ Kenyan coast revealed ten dugongs during November Diani-Chaie Lagoon 199^ and six dugongs during February-March 1996, TariBa.' ••KiMn, ..' Pcmba Island representing a significant decline in comparison to

earlier counts of over 50 animals in the 1960s and 1970s'^'''^". The most important dugong habitat in Kenya • * Clmaku Um Bagamoyo * can be found in the Lamu Archipelago. In Tanzania, the \ Dar as Salaam main centers of dugong population have been reported INDIAN OCEAN along the Pemba-Zanzibar channels and in the Rufiji- Kinondoni Mafia area"". The need for protection and management

of and dugong habitats Iseagrass beds! has been stressed'"'. The importance of East African seagrass

ecosystems for fisheries is gradually emerging from an increasing research effort on the role of the seagrass

meadows in this region as nursery, breeding and feeding grounds for marine fish and crustacean species 40 BO 120 160 200 Kilometers Mtwara* of economic importance such as shrimps [Penaeus]

"'. Map 7.1 and spiny lobster IPanu/Zri/sl'"^' Several fish species Kenya and Tanzania graze on seagrasses, notably rabbitfishes ISiganidae) and surgeonfishes lAcanthuridae), while parrotfishes western Atlantic as well as the Indo-Pacific revealed a [Leptoscarus spp.l preferentially graze the epiphytes clear genetic difference between tfie two ocean on the seagrass. Adult fishes, such as snappers, systems, but genetic uniformity within each of the two groupers, grunts and barracuda, feed on the infauna of ocean systems"". Based on these results it was seagrass beds while the diet of their juvenile stages is concluded that all plants Iwith this morphology! from mainly seagrass-derived detritus. Portunus pelagicus, the Indo-Pacific are Halodule uninervis while those in an important contributor to the crab fishery in the tropical western Atlantic are Halodule wrightif'^'. Bagamoyo and Dar es Salaam, is said to inhabit shallow Nevertheless. Halodule wrightii continues to be coastal habitats such as estuaries, sheltered bays and

reported in literature despite these field, culture and open sublittoral waters (all of which may include

" '". isozyme findings'" It appears therefore that there seagrass), where all stages of its life cycle are found'"'.

is a need for further analyses of chromosomal Significantly higher fish abundance and catch differences and physiological studies to determine the rates were found in seagrass beds in comparison to

relationship between nutrients and leaf morphology of bare sand areas in a study of dema trap fishery in the

Halodule species. coastal waters of Zanzibar, Tanzania'"". Similarly, 1 1 of

The seagrass beds in East Africa, as indeed the 99 fish species of Tudor Mangrove Creek (Kenya! elsewhere, harbor a diverse array of associated plant are typically associated with seagrass 16 percent of the and animal species. Detailed studies on seagrass total catch!'"', while 7A species of fish (in a total of 39 associates in this region have identified over 50 families] and 15 species of macro-crustaceans were species of macroalgat and 18 species of algal reported for the seagrass beds of and Paje epiphytes'^'"™', at least 75 species of benthic on Zanzibar'"'. At both of these latter sites. Genres

invertebrates"'""' - especially gastropods and oyena was the dominant fish species in the seagrass bivalves - several species of sea cucumbers'"' and at beds l>60 percent of the total catch).

least seven sea urchin species'"'''', various shrimp, Harvesting of bivalves (notably Anadara antiquata, lobster and crab species'"^"' and over 100 fish Anadara natalensis and Anadara uropigilemana, species'"""' in association with seagrass beds. This Gardium assimile, Gardium pseudolina, Gardium clearly underscores the importance of seagrass flavum and Scapharca erythraeonensis] and meadows for biodiversity conservation. gastropods (including Murex ramosus, Pleuroploca 84 WORLD ATLAS OF SEAGRASSES

Case Study 7.1 GAZI BAY, KENYA: LINKS BETWEEN SEAGRASSES AND ADJACENT ECOSYSTEMS

Gazi Bay, a semi-enclosed bay (15 km'l ca 50 km Bay attracted scientists to study the interlinkages

south of Mombasa, is characteristic of the creeks and between these systems in terms of dissolved bays along the East African coastline. Mangroves, nutrients and seston fluxes as well as shuttle move- seagrass meadows and coral reefs occur here as ments of fish"". Analysis of the stable isotope signa-

adjacent ecosystems. Mangroves are found along ture of the sediment carbon in the seagrass zone

small seasonal rivers on the landward side of the bay revealed significant carbon outwelling from the man-

and are drained by two tidal creeks. Extensive sea- groves, but deposition of particulate organic matter

grass vegetation is common among and between the rapidly decreased with distance from the forest, with

mangroves, where it functions as a trap reducing the most litter trapped within 2 km of the mangroves'".

flux of sediment, organic material and nutrients from However, marked decreases in the carbon signature

the mangroves to the ocean. Snorkeling in creeks and of seston flowing over the seagrass zone during flood

small rivers among the mangroves can be a sens- tides pointed to a reverse flux of organic particles

ational experience: the water can be very clear and from the seagrass zone to the mangroves, with the

the bottom is covered in a luxuriant growth of nearby coral reefs existing in apparent isolation.

seagrasses, traversed by mangrove roots where Direct flux measurements of both mangrove and

schools of juvenile fish hide from predators. Adjacent seagrass litter showed that trapping of mangrove

to the mangroves on the seaward side are intertidal litter by adjacent seagrasses is reciprocated by a

flats, intersected by some channels, and shallow retention of seagrass litter in the mangrove, and this

subtidal areas which stretch to the . Most give-and-take relationship is mediated by tides.

of this area is covered by various species of sea- Further research has indicated that the detntal

grasses and macroalgae, with the exception of a few cycling in the inner parts of the mangrove forest

sandy patches"''^'. Seagrasses in Gazi Bay cover an forms part of a rather closed system based on local

estimated total area of approximately 8 km'. The inputs, whereas cycling in the outer parts of the forest

maximum tidal range in Gazi Bay is 250 cm. IS tightly connected with the adjacent seagrass

All the 12 seagrass species of eastern Africa ecosystem'"'. Despite the presence of tide-mediated

are found in Gazi Bay. Macroalgae are among their chemical fluxes which allow one system to influence

most conspicuous floral associates. Sixteen species another, the input of mangrove carbon did not co-

of Chlorophyta. 4 species of Phaeophyta and 31 incide with enhanced leaf production of the dominant

species of Rhodophyta associated with seagrass beds subtidal seagrass Thalassodendron ciliatum"'".

in Gazi Bay have been identified'^'. Among these were Presumably, carbon outwelling from the mangrove

Euchema. Gracilaria, Ulva and Sargassum, all of coincides with only limited export of nitrogen and

which include species of potential economic value phosphorous, and the restricted effects of these

Average leaf production of Thalassodendron ciliatum, nutrients on the seagrass (if any! are masked by other

the most dominant seagrass species, ranges from local factors.

A.9 to 9.5 g/mVday"-'". A separate study of the growth Gazi Bay is typical of the major fishing grounds

and population dynamics of Thalassodendron in Kenya, most of which are located in shallow near-

ciliatum has shown that its vertical growth is the coastal waters due to a lack of sophisticated gear and

fastest reported for any seagrass to date 142 inter- motorized boats which would allow exploitation of

nodes. I.e. 42 leaves/yearl, whereas the horizontal deeper waters. Carbon isotope and delta "^N studies

growth rate (16 cm/year) is among the slowest"". As into trophic relationships in Gazi Bay allowed the

a result of the slow horizontal rhizome growth, shoot identification of three trophic levels, i.e. herbivores,

recruitment through branching of vertical shoots is zoobenthiplanktivores and piscivores/benthivores.

an important part of the clonal growth of this Seagrass beds were found to be the main feeding

population and so an essential component of the grounds providing food for all fish species studied in

production of Thalassodendron ciliatum. Gazi Bay, Kenya"". Seagrass plants were the major

Seagrass meadows are open systems subject source of carbon for four fish species studied in the

to nutrient impoverishment due to export processes bay They also contribute (together with mangrovesj

mediated by tidal inundation. The intriguing feature of to the particulate organic carbon for prawn larvae,

the occurrence, in very close proximity to one zooplankton, shrimps and oysters, hence their

another, of mangroves, seagrasses and corals in Gazi support for food webs'"'.

4 Kenya and Tanzania 85

trapezium and Oliva buibosa] for food Is common on found to be more sensitive to desiccation than subtidal

many of the intertidal areas Iwitfi or without seagrassi seagrasses with the exception of the species

in Tanzania. No data currently exist on the quantities Syrmgodium isoetifolium""^'. Desiccation tolerance,

collected from seagrass areas. Strombus gibberulus, however, may not be a trait that determines the vertical

Strombus trapezium and Cypraea tigris, all of which zonation of tropical seagrasses. The ability to tolerate are popular curio goods, are common in seagrass high irradiances, as well as the high nutrient inputs areas around Dar es Salaam'". Twenty species of sea from the shore, apparently allows the shallow species cucumbers, the most common of which are to occupy the uppermost intertidal zone. scabra. Hoiothuria nobilis, Bohadschia vitiensis, Seagrass beach cast material may contribute

Bohadschia argus. Thelenota anax, Stichopus significantly to beach stability, as implied by a study

chloronotus. Stichopus variegatus and Stichopus along the Kenyan coast'" "' Isee Case Study 7.21.

hemanni, are harvested from intertidal areas (including Detailed studies in Gazi Bay, Kenya, revealed seagrass beds! along the Tanzania coast for export'""'. significant carbon outwelling from the mangroves into

the adjacent seagrass meadows and a reverse flux of PRODUCTIVITY AND VALUE organic particles from the seagrass zone to the

Studies on the ecological processes and functioning of mangroves, with nearby coral reefs existing in apparent seagrass ecosystems in Kenya and Tanzania have isolation'" as far as particulate organic matter is

provided a better understanding of the natural factors concerned. Export of organic matter from mangroves in

limiting the growth and geographical distribution of Chwaka Bay (Tanzania) was also limited to a narrow seagrasses, environmental stresses and indirect fringe of seagrasses immediately adjacent to the values of seagrass ecosystems in this region. mangroves'"'. Despite the presence of tide-mediated

Leaf productivity of Thalassodendron ciliatum chemical fluxes, which allow one system to influence ranges from 4.9 to 9.5 g/mVday""'^"". Vertical growth another, the input of mangrove carbon did not coincide

rates of Thalassodendron ciliatum {A2 internodes. i.e. with enhanced leaf production of the dominant subtidal i2 leaves/yearl measured in Kenya are among the seagrass Thalassodendron ciliatum'"". fastest reported for any seagrass species to date, Carbon isotope and delta '*N studies on trophic whereas its horizontal growth rates 116 cm/year] rank relationships showed that seagrass beds were the among the slowest"" Shoot recruitment rates main feeding grounds for all fish species studied in Gazi

measured in seagrass meadows along the coasts of Bay, Kenya"". An experiment on feeding preference Kenya and Zanzibar were either the same as or larger showed that Catotomus carolinus IScaridael, the than shoot mortality rates, suggesting that the second most abundant fish in Watamu Marine National environmental quality in this region is still suitable for sustaining vigorous seagrass vegetation'"'.

tvlost factors that govern primary production,

including light and temperature, are relatively constant throughout the year in this region. However, the composition of the oceanic water and the amount of freshwater which enters the coastal areas are variable.

At several sites along the coast substantial seepage of freshwater occurs, as a result of which brackish water

is often found in areas cf seagrass beds'"''. Using nitrogen stable isotope signatures, groundwater was found to influence seagrass species diversity and abundance where Thalassodendron ciliatum dominated high groundwater outflow areas as opposed to Thalassia hemprichii.

Photosynthetic studies carried out in Zanzibar, Tanzania, indicate that seagrasses may respond favorably to any future increases in marine carbon

dioxide levels due to global climate change'""'. The enhanced photosynthetic rates by l-lalophila ovalis and

Cymodocea rotundata in the high, frequently air-

exposed, intertidal zone may have been related to a The catch from a trap fishing trip in the seagrass beds - mainly the capacity to take up the elevated HCO3" levels directly'"'. seagrass parrotfish Leptoscarus vaigiensis, some pink ear emperor

Furthermore, these tropical intertidal seagrasses were Lettirinus lentjan, and a grouper Epinephelus ftavocaeruleus. 86 WORLD ATLAS OF SEAGRASSES

Park, preferred pioneering short-lived seagrass ESTIMATED COVERAGE

species to climax species. The study also highlighted There are very few area estimates for seagrasses in

the role of grazing fish in influencing seagrass this region. Distribution maps of seagrasses are only abundance'™'. available for Mida Creek, Gazi Bay, Diani-Chale Lagoon Sea urchins mediate the competitive success of and Chwaka Bay. The recent UNEP Alias of Coastal different seagrass and fish species, in terms of Resources shows that seagrass beds occur throughout distribution and abundance. Sea urchins can reduce the 600-km-long Kenyan coastline in sheltered tidal

grazing rates of some species of parrotfish'^*', while the flats, lagoons and creeks, with the exception of the relative dominance of some of the sea urchin species coastal stretch adjoining the Tana Delta'". The testing of

indicates a high fishing on herbivorous a remote-sensing methodology for seagrass mapping

fish species'"'. , for instance, can in southern Kenya estimated the net area of vegetation

graze at a rate of 1.8 seagrass shoots/mVday at fronts cover to be approximately 33.63 km' within a stretch of that support a sea urchin abundance of 10.4 around 50 km of coastline'". Ground-truthing revealed individuals/m^'"'. The species composition of seagrass that most of these areas were dominated by pure

communities in reef environments appears to be stands of Thalassodendron cilialum.

partially affected by prey choices of the dominant Chwaka Bay on the eastern side of Island grazers. Parrotfishes and the sea urchin Echlnothrix (Zanzibar!, which covers more than 100 km', has appear to favor seagrass beds dominated by extensive mixed seaweed-seagrass areas, with Thalassodendron ciliatum, whde other sea urchin seagrasses representing between 50 and 80 percent of species such as . Diadema savignyi the macroflora biomass'^'. In Gazi Bay, which covers

and Echinometra mathaei favor areas high in Thalassia approximately 15 km', seagrass beds cover an area of hemprichif^^'. approximately 8 km' from the lower margin of the There have been lew studies on western Indian mangrove forest through the intertidal and subtidal

Ocean seagrasses to date. A recent bibliographic survey flats up to the fringing reef, with the exception of a few

of marine botanical research outputs from East Africa sandy patches''' "'. The Diani-Chale Lagoon along the between 1950 and 2000 yielded only AA papers and Kenyan coast measures roughly 6 km' with seagrass reports that dealt with seagrasses'^". Even baseline data beds covering up to 75 percent"". The Nyali-Shanzu-

on distribution are largely lacking'"'. In recent years, Bamburi Lagoon, with a total area of approximately 20

however, the number of seagrass publications from km'', IS 60 percent covered by seagrass beds''".

studies in the region has increased and efforts are At present, there are insufficient data for even a under way for integrated coastal zone management and "best guess" of total seagrass coverage in Kenya and

participatory management of marine protected areas Tanzania, but new mapping data are expected to including seagrass beds, indicating a growing become available from a recently started regional recognition of the important value of seagrass seagrass research project under the Marine Science for ecosystems. Management Programme (MASMAI.

Massive beaching of seagrass litter was reported as early as 1969 by an expedition to Watamu on the THREATS

Kenyan coast'"', rendering it unlikely that these The lack of a true continental shelf, stretching out no accumulations have increased over past or recent more than a few kilometers from the Kenyan and years"". Tanzanian shores, makes the coastal resources all the

No direct utilization of seagrasses in East Africa more vulnerable to overexploitation and influences has been reported'""" except for anecdotal reference to from activities on land'"'. In general, seagrasses the small-scale use of the leaves of Enhalus appear to have experienced fewer direct negative acoroides for weaving mats and thatching huts, and impacts than mangroves or coral reefs in the region,

the harvesting of their rhizomes by people of the but this may merely reflect the lack of any reliable

Lamu Archipelago in Kenya, who dry and then grind (quantitative) data. Deepening of channels lor ships at

them into flour for cooking what is locally known as harbors results in uprooting and burial of seagrass mf/Vn/)/"'. Quantitative data on such direct uses as plants by dredge-spoil'"'. well as catch statistics of the seagrass-associated Several beaches and adjacent coastal areas in

fisheries in this region are lacking, making it Kenya and Zanzibar are under increasing pressure

impossible to draw any conclusions regarding trends. from expanding tourism development'"'. High hotel

There are no published data on estimates of area loss density in close proximity to the beach is common"".

or degradation from the East African region"''^'"'. At Seagrass beds are locally damaged by motor boat

present, there are insufficient data for even a crude propellers and anchoring in the waters near these

estimate. highly intensive tourist areas'"^". While mooring buoys Kenya and Tanzania 87

have been deployed within the marine park to protect the coral reef, the seagrass beds remain unguarded, in some areas very popular vj\th tourists stretches of seagrass meadovi/ (deemed a nuisance to swimmers! are cleared by cutting and/or uprooting'^". In addition, the cumulative effects of raking, burying and removing seagrass beach cast material may have negative impacts on the functioning of the adjacent seagrass meadows"". Direct destruction of seagrass vegetation occurs by trawling activities. Commercial trawlers operating in the Rufiji Delta, Mtwara and coastal areas between Bagamoyo and Tanga (Tanzania!, as well as Ungwana

Bay in Kenya (where they reportedly have a fishing effort well beyond the potential sustainable yield'™'!, are non-selective and are destructive to the seabed. Illegal trawling - even during the closed season - occurs in Bagamoyo, Tanzania, where up to 80 percent of prawn bycatch is seagrass'"'. Trawling has also been reported as a major cause of mortality of the green turtle along the Kenyan coast'"'. Artisanal fishermen often connect separate navigable channels by digging through ln,pa^;s vi lounsm industry on seagrasses, Seagrass cover has intertidal flats in order to make way for their canoes, declined in front of a Mombasa nortfi coast beacfi hotel, causing damage to seagrass, albeit at a small scale'"'. Overfishing could pose a likely threat to seagrass sheltered lagoons, may be high but remain uninves- communities, as has been reported for the coral reefs tigated to date. in this region'"', although there are no direct reports to Increasing populations in coastal towns and confirm this. cities, such as Mombasa, Malindi and Dar es Salaam,

Recent agricultural activities in the Sabaki present a potential (but localized) threat to the coastal catchment have resulted in accelerated soil erosion seagrass resources from domestic solid waste, sewage and a tremendous increase in river sediments from disposal and dredge spoil dumping, all of which are some 58000 tons/year in 1960 up to as much as 7-U responsible for the declining water quality'"'. Seasonal million metric tons/year at present""'. Considerable blooming of Enteromorpha and Ulva species occurs amounts of sediment brought down by the river to the locally, especially in areas close to sewage discharge coral reefs and seagrass beds have been implicated in points from hotel establishments and municipal the low seagrass species composition at Mambrui'''". sewage"" "'. Although low organic loading is a feature

The apparent absence of seagrass beds in Ungwana of the well-flushed lagoon system, eutrophic conditions

Bay and northern Rufiji Delta"" might also be related and high bacterial contamination in the sheltered and to siltation by the Tana and Rufiji Rivers, but no studies semi-enclosed creeks have been reported'"'. have been conducted here. Significant heavy metal pollution from urban and

Oil pollution is one of the potential threats to industrial effluents has been reported in coastal waters seagrasses in East Africa owing to spillage of crude oil around Dar es Salaam"", affecting edible shellfish

in harbors and the risk posed by a large fleet (over 200 populations'"'. Reclamation of tidal flats, such as

oil tankers per day! from the Middle East across the proposed by the Selander Bridge coastal waterfront

coastal waters. There have been no major oil spills to reclamation project in Dar es Salaam, constitutes

date, except in 1988 when 5000 metric tons from a another potential threat to seagrass ecosystems.

pierced fuel tank in Mombasa destroyed a nearby area The expanding open-water mariculture farms of of mangroves and associated biotopes. The seagrass the seaweed Eucheuma spinosa currently cover around

species Halophits stipulacea and Halodule wrightii 1 000 ha of intertidal area on Zanzibar (Tanzania). The have not reappeared at the site since the spill'"'. In various adverse effects that seaweed farming has on

Tanzania, oil pollution along the coast - though not intertidal areas could well mar the positive picture of its

severe - is heaviest during the southwest monsoon"" socioeconomic benefits to coastal people. A marked The extent and specific effects of oil pollution on decline in seagrass cover from physical clearing of

seagrass ecosystems in East Africa's largest harbors, seagrass vegetation by seaweed farmers has been

Kilindini and Dar es Salaam, especially in creeks and reported"". Seaweed farming areas on Zanzibar appear 88 WORLD ATLAS OF SEAGRASSES

Case Study 7.2 SEAGRASS BEACH CAST AT MOMBASA MARINE PARK. KENYA: A NUISANCE OR A VITAL LINK?

The Mombasa Marine National Park and Reserve stretch of about 30 hotels, whose guests enjoy the (Kenya! encompasses a major part of the Nyali- white sandy beaches and other water sports Shanzu-Bambun Lagoon 120 km'l which has a within a stones throw of their rooms. Although the

maximum depth of 6 m. It is bordered by white beach cast phenomenon is seasonal and only sandy beaches on the landward and a fringing reef peaks during the low season, the burgeoning

on the seaward sides. Mixed seagrass com- tourism industry in this area considers it a

munities (dominated by Thatassodendron nuisance and would prefer its removal. Some of ciliatum] and associated seaweeds cover 60 the hotels employ staff to rake the seagrass

percent of the lagoon, which Is typical for most of material from the beach in the immediate vicinity

such lagoons along the Kenyan coast. Turbulent of the hotel and bury it under the sand. A detailed

water motion (exposure) in these areas is relatively study on the beach cast phenomenon showed that high compared with the sheltered creeks and bays burying the material does not significantly affect

and, due to hydrodynamic forcing, the spatial and decomposition rates"". temporal concentrations of nutrients and chloro- The same study, however, also pointed to the

phyll a do not reach eutrophic levels because the role of seagrass beach cast in contributing to

lagoon is well flushed'"'. beach stability By filtering out wave action, the

Large banks of macrophytes, 88 percent of beach cast material can reduce erosion of

which is seagrass, are deposited on the beaches beaches caused by /backwash processes. (beach cast] as the plants become detached from The beach cast material may also reduce beach the sea bottom by the surge effect from waves. erosion due to wind. Furthermore, the cumulative

This phenomenon is seasonal and controlled by effects of removing seagrass beach cast may tides and monsoon winds"'"'. The most intense intensify beach erosion either through the export

accumulations - as much as 1.2 million kg dry of sand in the process or the loosening up of weight along a 9.5-km stretch of beach - are compact sand, or through removal of the washed ashore during the southeast monsoons protecting material that slows wave action. The

when wind and current speeds, water column potential rate of beach erosion in this study was

mixing and wave height are usually greatest'^'. estimated at 'i92'l50 kg of beach sand (per

The Mombasa Marine Park is "fenced" by a removal) if beach cast material at any given

to have a lower abundance of meio- and macrobenthos custodianship of the Kenya Wildlife Service, a well- than unvegetated sandy areas, and may cause declining equipped parastatal organization that has received

seagrass productivity due to shading""". much donor support. Most, if not all, of the marine

protected areas in Kenya contain seagrass beds, but

POLICY RESPONSES detailed distribution maps of seagrasses in these

Kenya has been one of the most active countries in protected areas are not available.

marine conservation in Africa. The first marine In addition, several legal and administrative protected area was gazetted as early as 1968. Kenya's instruments address aspects related to the protection guidelines for establishing parks and reserves, and management of marine protected areas and thus safeguarding marine ecosystems and preserving rare (indirectly) of seagrass ecosystems. These include the species have been adopted from the United Nations protection of wildlife species, regulation of fisheries, Environment Programmes (UNEP'sl Action Plan for land planning and coastal developments, research and the East African Regional Seas Programme"". tourism. Dugongs and turtles are both listed as

There are no existing management practices to "protected animals" under the Wildlife Conservation protect existing seagrass beds from overexploitation or and Management Act and various initiatives for their

pollution per se. However, concern for the marine conservation have been implemented. By working

environment is demonstrated by the establishment of closely with respective local authorities, the Kenya

six marine protected areas covering a total area of 850 Wildlife Service may avoid approval of activities that km^ while an additional marine reserve has been could impact negatively on marine parks, as provided proposed. All protected areas are under the for under the Land Planning (1968) and the Physical Kenya and Tanzania 89

moment was removed from the entire beach 19,5- km stretch).

The total annual deposition of seagrass

beach cast was estimated to be in the order of 6.8 million kg dry weight, indicating that about 19

percent of the annual production of seagrass

meadows (14.7 million kg carbon/yearl in the lagoon passes through the beach, where

decomposition is accelerated through exposure to oxygen availability, drying and vigorous

fragmentation by wave action'"'. These processes speed up the release of dissolved nutrients and particles back into the adjacent ecosystems and

thus contribute to the detrital or energy pathways

The material was further found to contain over 23000 amphipods/m^ 3100 isopods/m^ and various other faunal groups, providing an

important food source for fishes during high tide.

The role of seagrass beach cast accumulations in nutrient regeneration processes and beach

stability, and as nursery sites and a source of food

for fish, crabs and shorebirds in the nearshore

zone, IS thus highly significant. Removing

seagrass beach cast, though desirable for tourism, would have negative impacts on the

health and functioning of adjacent seagrass beds,

on which artisanal fisheries and tourism itself rely

- Seagrass beach cast in Mombasa Marine National Parl<, 1995

significant amounts of seagrass litter are washed up

on the Kenyan beaches with each tide.

Planning (19961 Acts. Efforts are being made to protected areas in Tanzania"", the first two marine encourage environmentally sensitive tourism as one of parks, of which seagrass ecosystems are part, were the measures to achieve protection goals. A draft only recently gazetted in 1995. Despite considerable national strategy for sea turtle conservation is currently effort, the management of protected areas in Tanzania, under review while seagrasses have been considered in as in many developing countries, suffers from the most recent management plan of the Mombasa insufficient capacity and law enforcement. One of the Marine National Park and Reserve. stated objectives of the National Fisheries Policy and

Outside marine protected areas, however, Strategy, provided for by the Fisheries Act (19701. is to management and control overthe exploitation of coastal protect the productivity and biological diversity of and marine resources are virtually non-existent. coastal and aquatic ecosystems by preventing habitat Conservation of coastal and marine systems has destruction, pollution and overexploitation. concentrated its attention on either tourism-related or Tanzania's Coastal Management Partnership, directly exploitable marine resources such as shells and whose goal is to establish a foundation for effective coral reefs. Therefore it would seem that the important coastal zone governance, has produced the first functions of seagrass beds related to fisheries nursery national programme for Integrated Coastal Manage- grounds, or to marine primary production, their ment. Among the first outputs of this program are a contribution to energy pathways (involving a diversity of State of the Coast Report, a National Mariculture Issue organisms), or linkages with land-based activities are Profile, guidelines and a conflict resolution forum not at the top of the conservation agenda. dealing with such issues as trawling and dynamite

Since the recommendations to establish marine fishing. A draft national Integrated Coastal Manage- 90 WORLD ATLAS OF SEAGRASSES

ment Strategy is awaiting government approval. These Marine Park (by WWF - the World Wildlife Fund], and in

initiatives and, more so, the process have raised the Kinondoni [Kinondoni Coastal Area Management

profile and level of understanding of the importance of Programme]'™'. coastal and marine resources, including seagrass beds. Implementation of integrated coastal zone AUTHORS

management initiatives in Tanzania is currently under CA, Ochieng and PLA. Erftemeijer, WL 1 delft hydraulics, PO. Box 177,

way in Tanga Iby lUCN-The World Conservation Union), 2600 MH Delft, the Netherlands.. Tel: +31 I0]15 285 8924. Fax: +31 I0]15

Zanzibar ( Conservation Project], Mafia 2858718. E-mail: paul.erltemeijer0wldelft.nl

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40 Kamermans P, Hemminga MA. Marba N, Mateo MA. Mtolera M. Development Authority, Mombasa. 74 pp,

Stapel J [2001]. Leaf production, shoot demography, and flowering 58 Sanders MJ. Gichere SG, Nzioka RM [19901. Report of Kenya

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41 Duarte CM. Marba N, Hemminga MA [19961. Growth and population fish on the Kenyan coast: The effects of protective management

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lagoon. Atjuaf/c Botany 55: 1-11. Symposium, pp 261-266.

42 Kamermans P, Hemminga MA, Tack JF. Mateo MA, Marba N. 60 Katwijk van MM. Meier NF, van Loon R, van Hove EM, Giesen WBJT,

Mtolera M, Stapel J. Verheyden A [in pressl. Groundwater Effects van der Velde G. den Hartog C (19931. Sabaki River sediment load

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46 Ochieng CA [19961. Environmental Impact Statement on the Shanzu area. 74 pp.

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Mombasa. 58 pp. Coastal Regional Headquarters, Mombasa. 92 WORLD ATLAS OF SEAGRASSES

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Zanzibar, 8-12 May 1995. 2i pp.

67 Olafsson E, Johnstone RW, Ndaro SGM [19951 Effects of intensive

seaweed farming on the meiobenthos in a tropical lagoon. Journal

of Experimental Marine Biology and Ecology 191111:101-117. Mozambique and southeastern Africa 93

8 The seagrasses of MOZAMBIQUE AND SOUTHEASTERN AFRICA

S.O. Bandeira

F. Gell

Thirteen seagrass species occur in Mozambique Thaiassia hemprichii are the dominant subtidal sea- and 12 in the remaining southeastern African grass species in Mozambique. A detailed comparison region. Madagascar has nine common species. has been made of the former growing along the rocky

Five species occur in South Africa, seven in Mauritius and sandy coasts of southern Mozambique'". Leaves and up to ten in Comoros and Seychelles" "''. Ruppia appear to grow faster on plants in the rocky areas 120- mantima, recently defined as a seagrass'"', is also a 26 g/m'/day and up to 57 mm'Vdayl than in sandy (8-10 dominant species in the southeastern Africa region. g/mVday and up to 22 mmVdayl. Leaf biomass in rocky

areas is more than twice that of sandy (258 g/m^ and

BIOGEOGRAPHY 12/i g/m' respectively! and beds are characterized by a Mozambique much higher shoot density (i561 shoots/m' and 888 The Mozambican coast can be divided into three shoots/m" respectively). regions: a sandy coastline from the southern end of the The underground biomass of Thalassodendron country to the Save River; an estuarine coastline from ciliatum IS presumably relatively high in sandy the Save River up to around 500 km north of the environments because total biomass (862 g/m'1, while

Zambezi River; and a rocky limestone coastline, significantly lower than in the rocky seagrass beds typically surrounded by coral reefs, which runs from (1070 g/m'l, is comparable. Although possibly slower the Zambezia province up to the northern end of the growing, the Thalassodendron ciliatum plants in the country, and also covers the Tanzanian and Kenyan sandy habitat have wider (1.^ cm ±0.11 and longer coasts'*'". Seagrasses abound in the sandy and 112.51 cm ±0.61 leaves than in the rocky habitat (0.7 cm limestone areas. ±0.1 and 8.2 ±0.5 respectively!. The b'omass of

Seagrasses in general occur in mixed seagrass epiphytes on Thalassodendron ciliatum plants is an stands, especially in intertidal areas. The three order of magnitude higher in the rock (512 g/m^| than in dominant mixed-seagrass communities on the sandy the sand (iO g/m^l, and consequently these organisms substrates of southern Mozambique consist of account for nearly half (48 percent) of the combined combinations of Thaiassia hempnchii, Halodule seagrass and epiphyte biomass, compared with just 5 wrightii, Zostera capensis, Thalassodendron ciliatum percent in the southern sandy-bottom beds. and Cymodocea serrulata"'. Enhalus acoroides, Halophila stipulacea and

In contrast, the seagrass communities of the Halophila minor are found only in northern more northerly limestone areas are quite different, with Mozambique while pure stands of Zostera capensis are seagrasses tending to occur intermingled with found only in the south'"". Pioneer species observed in seaweed species'". Here, the dominant botanical Mozambique include Halodule wrightii, Halophila communities also include Thaiassia hemprichii and ovalis and Cymodocea serrulata. The first two species Halodule wrightii, but species such as Gracilaria act as pioneers in exposed sandy areas close to the salicornia, Halimeda spp. and Laurencia papillosa coastline, whereas Cymodocea serrulata is a pioneer in occur mixed with Thaiassia hemprichii, and Sargassum silted channels. spp. with Thalassodendron ciliatum. Elsewhere Zostera capensis and Halodule wrightii also form South Africa mixed beds. Zostera capensis is most widespread and one of the

In general Thalassodendron ciliatum and dominant seagrass species in South Africa. It occurs M

tji 94 WORLD ATLAS OF SEAGRASSES

N * QuinmtwAn.hipclui.\30° S ,' A COMOROS__ Table 8.1 MOZAMBIQUE.? „,„„,;^«^, / Area cover and location for the seagras Zoslificafensis'm ZAMBIA J Term.. Lumbo-* Vl-Uoo ^1 South Africa .' G»

•

Mo=m,b,^,a- MADAGASCAR ''T"'"'^r' ZIMBABWE , .' Estuary Area Climate Estuary

; ''- ; Clhiiwel name Ikm'l classification J Ulnhassoro

BOTSWANA y • f ^ St Lucia 1.81 Subtropical Estuanne lake \ Bicanjro 1 | Mbashe 0.01 Subtropical Permanently open

Mlalazi O.Oi Subtropical Permanently open Inhata IJand J* Mngazana 0.02 Subtropical Permanently open \ ,- SOUTH AFRICA , J % Kwa^iilii-Nalai Mtakatye 0.04 Subtropical Permanently open 30- S / Xora 0.01 Subtropical Permanently open • __ ^. INDIAN OCEAN Knysna 3.48 Warm temperate Estuanne bay 200 40O 600 600^1000 Kllonnetas Klein 0.37 Warm temperate Estuanne lake 20° E ^ Swartvlei 0.23 Warm temperate Estuanne lake Map 8.1 Keiskamma 0.12 Warm temperate Permanently open

Mozambique and southeastern Africa Keurbooms 0.64 Warm temperate Permanently open

Krom Oos 0.02 Warm temperate Permanently open

N 5G'E Qora 0.08 Warm temperate Permanently open A INDIAN OCEAN Swartkops 0.16 Warm temperate Permanently open

Hartenbos 0.01 Warm temperate Temporarily closed

SEYCHEUES Kabeljous 0.02 Warm temperate Temporanly closed Praslin ^^ ' Ngqusi\lnxaxo 0.01 Warm temperate Temporanly closed

Total 7.07 '^Lj Digue

Source- Colloly"" S,y,l,,-IUs Bank ^. Silhouene ^^. ^

mostly in estuanne w/aters along a number of estuaries

• Anse aux Pins from Kwazulu-Natal to tfie western Cape region. Mahe Anotfier important location witti seagrass

species is found off Kwazulu-Natal. Here, a number of

9 18 27 36 45 Kilometers rocky protuberances into ttie sea are mostly dominated by Thalassodendron cilialum adapted to

Map 8.2 live in rocky habitat together with seaweeds"". These

The Seychelles rocky areas generally experience strong water dynamics and winds similar to those of southern N Mozambique"'.

A -'.^. 20° h The distribution of Zostera capensis in southeast Mont Choisy \ South Africa is well recorded. It grows in 17 estuaries • Poudre d'Or (Table 8.1). Individual beds are small, generally only a

Poste Lafayette few hectares, and the total area covered by seagrass is * ? Port Louis about 7 kml INDIAN •Wbion O C E A N \ Madagascar IWAURITIUS f Little is known about the relative dominance

' of seagrass species in Madagascar although it is likely that in the southwest of the country they are ; y similar to the species from the limestone areas of -*.. Mozambique, with most of the meadows being domin-

5 10 15 20 25 KjIcxnelefS ated by Thalassodendron ciiiatum and Thalassia hemprichii. Seaweeds are also a common feature in

Map 8.3 the intertidal and subtidal seagrass areas of Mauritius Madagascar"'". u Mozambique and southeastern Africa 95

Mauritius ciliatum, both of which can grow to over 1 m in height, Thalassodendron ciliatum, Halodule uninervis and and the smaller species Cymodocea rotunddta and

Syringodium Isoetlfolium appear to be the most Cymodocea serrulata. Small seagrass species le.g. common seagrass species in Mauritius"". Syringodium isoetifolium, Halophila spp. and

Halodule spp. I are present in small quantities, often

Comoros forming an understorey in stands of larger species. In

Little is known about the seagrass meadows of quadrat surveys of the Montepuez Bay seagrass beds, Comoros. Being located less than 400 km east of the the most common seagrass types were stands coastline of Mozambique and sharing a similar climate, dominated by Enhalus acoroides. The most common Comoros may have similar meadows to northern combination of seagrasses found was Enhalus Mozambique with mixed seagrass species in intertidal acoroides with Halophila ovalis, which were mainly

areas and subtidal seagrass species dominated by found together in areas that were exposed to the air at broad-leaved species such as Thalassodendron very low tides.

ciliatum. Such a predominance of Enhalus acoroides is

unusual in the region and, even within the Quirimba Seychelles Archipelago which has extensive seagrass beds, Seychelles is composed of 115 granite and coral Montepuez Bay was the only area dominated by

islands. Seagrass meadows are dominated by Enhalus acoroides. Other subtidal seagrass beds in the Cymodocea serrulata. Syringodium isoetifolium and Quirimba Archipelago were dominated by Thalasso-

Thalassia hemprichii occur at Anse aux Pins'^' on the dendron ciliatum. Dense meadows of tall (often

main island of Mahe. Shoot density varies from 1 093 to between 50 and 100 cm| Enhalus acoroides were home

1 107shoots/m''in Cymodocea serru/ata plants, 1 123 to to a diverse range of invertebrates and fish, and the

1 761 in Syringodium isoetifolium and 540 to 627 in seagrass itself was covered in epiphytes, altogether

Thalassia hemprichiP'. Thalassodendron ciliatum is constituting a complex habitat. Over 30 species of algae

also common in subtidal areas down to depths of 33 m were identified living on or in association with the

throughout the Seychelles"^'. seagrass""'. Fishers in Montepuez Bay target shallow areas of Enhalus acoroides for their main fishing

SEAGRASS FISHERIES IN MOZAMBIQUE activities, whilst women collect invertebrates in the

The Quirimba Archipelago is a chain of 32 islands off intertidal seagrass beds dominated by Thalassia the coast of northern Mozambique, running from north hemprichii. Although the direct use of seagrass plants of the town of Pemba up to the Tanzanian border One of has been reported from other places, this was not the largest and most populated islands in the chain is observed in the Quirimba Archipelago.

Quirimba. Quirimba is 6 km long by 2 km wide and has a population of 3000. This island is separated from the Fishing methods mainland by the Montepuez Bay. The islands main Seine nets were set from small sail-powered boats by fishery is located in the shallow seagrass beds of the teams of between five and 12 men. Fishermen in the

bay. and this seagrass fishery is the mam source of water kept the net in place and drove the fish into the net

income and protein for people on the island. In 1996 as it was hauled into the boat. Seme net fishing was and 1997 part of the Darwin/Frontier Quirimba carried out in shallow water, from 1 to 8 meters deep, in Archipelago Marine Research Programme studied the areas of Enhalus acoroides. The nets used were

Quirimba fishery which is dependent on a diverse approximately 100 m in length with a main mesh size of '". seagrass ecosystem'" 4 cm stretch and a cod-end of 2 cm stretch, or less. The

Montepuez Bay is between 1 and 10 m deep and mean duration of a fishing trip was about five hours and

has extensive intertidal flats and banks, large areas of the mean catch per trip was 75 kg. Catch per unit effort which are covered in seagrass. The bay takes its name was 3.6 kg of fish per man-hour spent fishing or 2 kg of from the Montepuez River, which enters the southwest fish per man-hour spent at sea. The net catches were of the bay from the Mozambique mainland. Ten species highly diverse, with a total of 249 fish species in 62 of seagrass are present in the bay: Enhalus acoroides, families identified from more than 46600 fish sampled"".

Thalassodendron ciliatum, Cymodocea rotundata, The fishers also caught invertebrates in the seine nets,

Cymodocea serrulata, Syringodium isoetifolium, particularly squid. Approximately 30 fish species were

l-lalodule uninervis, Halodule wrightii, Halophila ovalis, common in the catch. The most important species in the

Halophila stipulacea and Thalassia hemprichii. net fishery in terms of weight were the African The intertidal seagrass beds are dominated by whitespotted rabbitfish Siganus sutor (24 percent); the Thalassia hemprichii. Subtidally, the most abundant pink ear emperor Lethrinus lentjan (12.2 percent); the species are Enhalus acoroides and Thalassodendron seagrass parrotfish Leptoscarus vaigiensis (1 1 percent);

Wl %J

r/-( 96 WORLD ATLAS OF SEAGRASSES

less than 15 cm long and many were juveniles. Virtually ^^3^^^ all the fish caught in the seine net fishery were eaten. Amongst the more unusual food species that were

common in the fishery were the tailspot goby Ambtygobius albimaculatus and the three-ribbon W^ -^ wrasse Stethojulls stngiventer. -'-^ The traps used in Montepuez Bay are known

locally as marema. They are of an arrowhead design and constructed from woven bamboo panels secured together with palm fibers. Marema were set by

H fishermen from outrigger canoes in shallow areas of Bj^K'-^^^^^^^ Enhalus acoroides at low tide, and were hauled the

following day at low tide. The traps were sometimes baited with crushed Terebralia snails collected from mangrove areas, or with sguid, but often the traps were

not baited at all. The traps were weighed down with stones and placed amongst long, densely growing Enhalus acoroides (the fishermen said that this

seagrass was very important for keeping the traps in

A marems fish trap in an Enhalus acoroides bed, Mozambique place in the strong tidal currentsl. The mean daily catch for a fisherman setting AO traps was nearly 7 kg of fish, the variegated emperor Lethrinus vanegatus (7.4 although catches could be as high as 27 kg per trip. percent); the blacktip mojarra Genres oyena (6.3 percent) The catch per unit effort for the trap fishery was 2.2 kg and the spinytooth parrotfish Calotomus spinidens (3.2 of fish per hour spent fishing and the mean catch for a

percent!. The majority of fish caught in seme nets were trap set for 2A hours was 0.2 kg of fish. Trap catches

Case Study 8.1 AND AREA, SOUTHERN MOZAMBIQUE

Seagrasses at Inhaca Island and N/laputo Bay area in the subtidal fringe, occurs in homogeneous stands

cover more than 80 km'. At Inhaca Island the except in some areas where it is also accompanied seagrasses alone cover around 50 percent of the by a band of Syringodium isoetifolium parallel to the

entire intertidal area'". The diversity of seagrasses is coastline. When Thalassia hemprichii and Halodule

very high, especially at Inhaca Island where eight wrightii co-occur in mixed species communities,

seagrasses species can be found in just one Thalassia hemprichii is found in small depressions hectare'". Nine seagrass species have been whereas Halodule wnghtii occupies elevated areas identified m the area namely: Cymodocea rotundata, which are exposed at low spring tides. Cymodocea serrulata, Halodule uninen/is, Halodule Seagrass meadows in Maputo Bay region are

wnghtii, Halophila ovalis. Syringodium isoetifolium. widely used by the people who collect, by hand, Thalassia hemprichii, Thaiassodendron ciliatum and from them, the most common being Zostera capensis"'. These seagrass species are mussels [Anadara natalensis, Cardium flavum,

grouped in three main dominant seagrass com- Modiolus phillipinarum], oysters [Pinctada capensis], munities: Thaiassodendron ciliatum/Cymodocea gastropods {Conus betulinus, Strombus gibberulus] serrulata. Thalassia hemprichii/Halodule wnghtii and sea urchins (e.g. Salmacis bicolores, and Zostera capensi^"''. Zostera capensis shoot Tripneustes gratilla]. They also use the meadows for

density is higher at Inhaca 12880 shoots/m'l than at fishing using traditional techniques, for species such

Maputo Bay [1 285 shoots/m'l as are leaf, rhizome as Crenidens crenidens, Gerres acinaces, and root biomass'"'. Leiognathus equulus. Lithognathus aureti, Liza The species Thalassia hemprichii and macrolepis, Lutjanus lulviflamma, Platycephalus

Thaiassodendron ciliatum tend to occupy deeper indicus, Pseudorhombus arsius, Rhabdosargus areas far from the coastline whereas Halodule sarba, Scarus ghobban, Siganus sutor and Terapon

wrightii and Cymodocea serrulata tend to occupy jarbua, and crustaceans such as Matuta lunaris and

shallow areas closer in. Thaiassodendron ciliatum. Portunus pelagicus'"''-^^'. The

M

y^y Mozambique and southeastern Africa 97

were dominated by the parrotfish Leptoscarus for Enhalus acoroides greatly exceeded that for other vaigiensis. which accounted for over 74 percent of the common seagrass species, Thalassodendron ciliatum fish caught by weight. Other Important species included or Cymodocea spp. Catch compositions from the three the parrotfish Caiotomus spinidens 15 percent by different seagrass species were also different. Catches weight], the rabbltfish Siganus sutor (4 percent], the from Enhalus acoroides beds were dominated by the dash-dot goatfish Parupeneus barberinus 14 percent), parrotfish Leptoscarus vaigiensis as the fishermen's the blackspot snapper Lutjanus fuiviflamma 13 percent] catches were, but catches from Thalassodendron and the flagfin wrasse Pteragogus fiagelllfera 12.5 ciliatum beds were dominated by the file fish percent]. A total of 61 species of fish were Identified Paramonacanthus barnardi, and catches from fronn 3500 fish sampled from the trap fishery, with Cymodocea spp. by the snapper Lutjanus fulviflamma. about 16 of these species appearing commonly in the fishery. A wide variety of Invertebrates entered the Invertebrate fishery traps. Including swimming crabs [Portunidae] which Women did most of the collecting of seagrass inver- were kept for use as food. tebrates that could be achieved without a boat. They

Spatially referenced catch data from the seme net walked out over the seagrass beds at low tides and fishery was used to Identify the fishing sites In collected bivalves by hand. On spring tides, some women

(vjontepuez Bay with the highest mean fish catch per traveled in groups by boat to some of the larger banks In unit effort. These were also the sites with the highest the bay that become exposed at low tide. mean percentage cover of seagrass and highest The mam species they collected were the ark shell seagrass biomass. This suggests that seagrass cover Barbatia fusca and the pinna shell Pinna muricata. found and biomass may Influence fish biomass and fishery in sand in seagrass beds, and the oyster Pinctada nigra productivity. In experimental trap fishing, the prefer- which grows on the seagrass plant itself. These shellfish ence of trap fishermen for areas of Enhalus acoroides were dried and most of them were sold on the mainland to other species of seagrass was shown to be well for higher prices than they would fetch on the island, founded. In these experiments the mean catch per trap particularly the pinna shell which is a local delicacy'"'.

Holothuna scabra. presently endangered in many industrial area. Sedimentation due to erosion and

parts of the country, was earlier heavily collected by floods further diminishes local seagrass coverage

the local people at Inhaca and north of Maputo city around Maputo. Trampling and the heavy concen-

and sold for export to Asia. The same is true of tration of fishing and tourist activities directly disturb

Holothuna atra. but to a lesser extent. seagrass meadows at Inhaca Island's mam village.

More than 20 nets are set daily around Inhaca Fishing in very shallow water is another disturbance.

Island from boats and by people walking on the The combination of all these factors places heavy beach, and around 100 people may be seen collecting pressures on the extensive seagrass meadows, and

edible organisms during the spring low tides'". To the has already caused a disappearance of Zostera

north of Maputo city, at the fishing village of Bairro capensis from In front of Inhaca's mam village'".

dos Pescadores, close to 50 people dug up seagrass Some priority areas for inten/ention to reduce meadows at spring low tide for collection of these disturbances include increased monitoring

invertebrates, mainly bivalves, in the mid-1990s'". and reduction of sewage disposal, industrial pollu- Recent counting estimated around 200 people tants and port activities. At Inhaca Island, only the

involved in this activity, which includes digging the seagrass beds located close to coral reefs are under

Intertldal areas for the same purpose. Seagrasses protection. This protection should be reviewed to have also been reported as being used for alluring target the conservation of seagrass areas with a high

and bewitching at Inhaca Island'" and the dried concentration of threatened and depleted in- detached leaves of Thalassodendron ciliatum as vertebrate species such as holothurians and

being used to fill piUov.'s. seastars, e.g. Holothuna scabra and .

The seagrasses of the area are under consider- The Thalassodendron ciliatum communities occur-

able stress from a variety of sources. Sewage ring in rocky protuberances In the sea habitats have disposal along the Maputo coastline threatens sea- only recently been described. This form of seagrass

grasses there, with polluted areas tending to be only occurs In sandstone rocks facing the strong covered by seaweeds Ulva spp. and Enteromorpha waves of the Indian Ocean'". Few similar areas exist

spp. Instead of seagrass. Additional pollution, in Mozambique and therefore some kind of pro-

especially oil spills, comes from the city harbor and tection should be put in place for their conservation

\ 98 WORLD ATLAS OF SEAGRASSES

Some fishermen went out on the seagrass beds was apparently sustainable. The seine net fishery did

in small canoes to dive with a masl< to collect appear to have some negative effects on the seagrass invertebrates, mainly sea cucumbers, and mollusks beds. The nets were often dragged along the bottom such as the tulip shell Pleuroploca trapezium and the and substantial amounts of seagrass, sponges and murex . Sea cucumbers were one small corals were sometimes brought up with the nets.

of the more valuable seagrass residents and were Trampling of intertidal seagrass was kept to a

dried and sold across the border in Tanzania, to be minimum by the use of small paths across the

exported to markets m the . During the study seagrass that restricted the trampling damage to a

period fishermen reported the virtual disappearance small area. The main threats to the sustainability of the of sea cucumbers from the seagrass beds of seagrass fishery came from external sources, mainly Montepuez Bay, and attributed this to overexploitation unregulated itinerant fishers and commercial sea

by local and itinerant fishers. Fishermen involved in cucumber fishing for international trade. On a larger

the seine net and trap fishery would also collect scale, potential threats came from upstream activities

murex. tulip shells and sea cucumbers when they got in the catchment of the Montepuez River - particularly

the opportunity. Tulip shells were collected for their leading to changes in sedimentation

opercula which were sold to traders in Tanzania. rates. Murex were eaten and the shells of these and other With so many people relying on the seagrass beds mollusks were collected and burnt for lime that was of Montepuez Bay for their livelihoods, and with the

used locally in building. paucity of alternative employment or sources of

Subtidal surveys identified 34 species of large protein, their conservation and sustainable use is vital.

invertebrates which were associated with the seagrass One of the reasons that the resources of the Montepuez

beds. Commonly observed invertebrates that were not Bay seagrass beds are so widely used is that the habitat

collected locally included the sea urchins Diadema is so accessible, even to those with the most limited

setosum and Tripneustes gratilla, the sea cucumber resources. Much of the seagrass can be reached on foot

Synapta macutata and the Pentaceraster at low tide, and even the deeper areas are close to

tuberculatus and Protoreaster [incki. shore and are sheltered from the heavy seas that the

eastern coast of the island is subject to. At the time of Local value of seagrass resources this study Quirimba Island had rich and diverse marine The seagrass fisheries of Montepuez Bay supported resources including mangrove forests and extensive over 400 fishermen on Quirimba Island alone and many coral reefs on the east coast. However, few fishers

more in the mainland villages and from other islands in utilized the reef resources because of the difficulties of

the vicinity. More than a hundred women from Quirimba accessing the exposed reefs in their traditional fishing

also collected invertebrates in the seagrass beds. In vessels. This issue of the accessibility of seagrass beds

total over 500 people were involved in the seagrass is seen in other places where fishers with small boats,

fisheries of Quirimba. out of a total population of 3000. or on foot, are able to fish in seagrass beds in shallow The total fish catch from the 35 km^ seagrass beds of sheltered bays or lagoons. A priority for seagrass

the whole bay was estimated at around 500 metric tons research should be to look at how best to manage per year, or 14.3 metric tons per km' per year. open-access, multi-user seagrass systems such as

This figure does not include invertebrates, but is still Montepuez Bay, to ensure their sustainable use, and to high compared with many tropical reef and estuarine conserve biodiversity. The Quirimba Island seagrass

fisheries. A minimum estimate for annual invertebrate fishery is a clear, and rare, example of the direct value

collection from seagrass beds around Quirimba was 40 of seagrasses to local communities. metric tons per year

In the study period, the fish caught in Montepuez HISTORICAL PERSPECTIVES AND LOSS Bay had an estimated annual saleable value of ca The digging of Zostera capensis beds to collect bivalves

US$120000, based on prices paid for fish locally Roughly has dramatically depleted the seagrass cover at Bairro

half the fish caught was consumed by the fishers and dos Pescadores Inear Maputo, Mozambique) from a

their families or exchanged for other goods or services. cover of around 60 percent or more to 10 percent or

The other half was dried and traded on the mainland by less in the last ten years (Figure 8.11. This activity lasts

the owners of the net fishing boats, or other traders who for the entire spring tide period spanning about 1 5 days buy the surplus from trap fishermen. each month. The bivalves are collected mainly for food.

It IS expected that this activity will eventually

Management issues completely destroy the Zostera capensis beds at Bairro

During the study period the local fishery seemed to dos Pescadores, and that the food security of the local have a relatively low impact on the seagrass beds and population will suffer as a consequence.

74 a

Mozambique and southeastern A f r i c 99

Sedimentation due to floods has buried sea- high use of fertilizers in the sugar cane industry, and grasses in Maputo Bay and Inhassoro. In the heavy specifically by the eutrophication of coastal lagoons floods in southern Mozambique in 2000 around lU km" that is caused when they leach into these shallow of seagrasses may have been buried here. Harbor contained areas. Seagrass beds are being dredged development, sewage and coastal development in and destroyed to provide bathing and skiing areas for areas of southern Mozambique have further diminished tourists. Sedimentation, sewage disposal and sand seagrass coverage. Heavy concentrations of artisanal mining are among other threats to Mauritius fishing boats in combination with intense trampling in seagrasses. low tides have also caused reduction of seagrass In Anse aux Pins, Seychelles, sedimentation. species at Inhaca Island,

In Mauritius seagrasses are threatened by the

Table 8.2

Figure 8.1 Seagrass cover and area lost in Mozambique

Digging of Zostera capensis meadows at Vila dos Pescadores, near l^aputo city Site name Main seagrass Area Area lost

species lkm-| Ikm-'l

Quinmba Cr Cs, Ea, Hm, 45

Archipelago Ho, Hs, Hw, Tc, Th

Mecufi-Pemba Hm, Ho, Hs, Hu, 30

Hw, Si, Tc, Th, Zc 0.02

Fernao Veloso Cr, Cs, Ea, Hm, 75

Ho, Hu, Hw, Si, TcTh

Quissimajulo Th 2

Relanzapo Tc, Th,

macroatgae 8

Matibane- Cr Hw, Tc, Th 34

Quitagonha

Island

Chocas Mar- TcTh 19

Cabaceira Grande-

Sete Paus Island

Mozambique Cr Cs, Hm, Ho, 15 3

Island-Lumbo- Hu, Hw Si, a. Ptioto taken in 1994 - hunl

- then placed upside down plant cover is still higfi. Island Tc 1

Inhassoro- Cs, Tc, Th 25 10

Bazaruto Island

Inhambane Bay Hw 30 0.5

Xai-Xai Tc, macroalgae 0.04

Bilene Rm, Hu 3

Maputo Bay Ho, Hw, Tc, Th, Zc 37 14

Inhaca Island Cr Cs, Ho, Hu, 46 0.03

Hw, Si, Tc, Th, Zc

Inhaca-Ponta Tc, macroalgae 69

do Ouro

Total 439.04 27.55

Notes: Cr Cymodocea rolundata; Cs Cymodocea serrulata;

Ea Enhaius acomides; Hm Halophila minor: Ho Hatophila ovalis; | Hs Halophila stipulacea: Hu Habdule jnmervis. Hw Habdule

wnghtii; Rm Ruppia mantima: Si Synngodium isoetilolium:

Tc Thalassodendron ciliatum: Th Thatassia hempnchii; b. Pfioto taken in 2002 - plant cover is very low and in most areas Zc Zosfera capensis

the seagrass has already disappeared.

f WORLD ATLAS OF SEAGRASSES

salinity and decreased water quality associated with a PRESENT COVERAGE river effluent disctiarge liave adversely affected Mozambique has a total of /i39 km' of seagrasses (Table seagrasses'". Flooding in estuaries is the mam threat to 8.21. There are 25 km' around Inhassoro and Bazaruto the survival of Zostera capensis on the South African Island, 30 km' at Mecufi-Pemba and 45 km' in the east coast. southern Quirimba Archipelago. The largest seagrass Other areas where seagrass cover has been lost beds occur at Fernao Veloso, Quirimba and Inhaca- include Pemba. Mozambique Island, Inhambane Bay Ponta do Ouro. Additional inventories are needed, and Inhaca Island liable 8.2). The total known historical particularly in remote coastal areas. In South Africa

loss of seagrasses in Mozambique is 27.55 km', Zostera capensis covers a total area of just over 7 km': although some of the areas affected by the 2000 floods other seagrasses species cover smaller areas. While have already regained seagrass coven extensive seagrass meadows do occur in Madagascar,

In Mauritius, seagrasses have diminished from Mauritius, Comoros and Seychelles, the exact area is areas such as Albion iHalodule uninervis], Poudre unknown. d'Or, Mont Choisy and Poste Lafayette [Syrmgodium

isoetifoliunn] though the actual area lost is unknown. AUTHORS

Similarly areas covered by Zostera capensis in Salomao 0. Bandeira, Department of Biological Sciences, Universidade

estuaries in Kwazulu-Natal. South Africa, are believed Eduardo Mondlane, P.O. Box 257, Maputo, Mozambique. Tel: +258 1011 to have been seriously depleted by periodic heavy 491223. Fax: +258 1011 492176. E-mail: sbandBzebra.uem.mz floods"" without measurements being available.

Nothing is known about the loss of seagrass from Fiona Cell, Environment Department, University of York, Heslington, York Madagascar, Comoros or Seychelles. Y010 5DD, UK.

REFERENCES 12 Colloty BM [2000], Botanical Importance of Estuaries of the Former

thesis, University of Port Elizabeth. 202 1 Titlyanov E, Ctierbadgy I, Kolmakov P [1995]. Daily vanations of Ciskei/Transkei Region, PhD pp.

primary production and dependence of photosynthesis on 13 Rabesandratana RN [1996]. Ecological distnbution of seaweeds in

irradiance in seaweeds and seagrass Thatassodendron ciUalum of two fringing coral reefs at Taliara ISW of Madagascar] In: B|6rk 1^,

the Seychelles Islands. Photosynttietica3V. 101-115. Semesi AK, Pedersen M, Bergman B ledsl Current Trends in

2 Bandeira SO [20001. Diversity and Ecology of Seagrasses in Marine Botanical Research in East African Region. SIDA/SAREC, Mozambique: Emphasis on Thatassodendron Citiatum Structure, Uppsala, pp 141-161. Dynamics, Nutrients and Genetic Variability PhD Ihesis, Gdteborg 14 Dulymamode. Personal communication. University 15 Parnik T, Bil K, Kolmakov P, Titlyanov E [19921. Photosynthesis of

3 Ingram JC, Dawson TP [20011. The impacts of a river effluent on a the seagrass Thalassodendron ciliatun): Leaf and carbon

coastal seagrass habitat of Mahe, Seychelles. South African . Photosynthetica 26: 213-223. Journal ol Botany bl-.m-W 16 Cell FR [19991. Fish and Fishenes in the Seagrass Beds of the

4 Short FT, Coles RG, Pergent-Martini C [20011. Global seagrass Quinmba Archipelago, Northern Mozambique. PhD thesis.

distribution. In: Short FT, Coles RG ledsl Seagrass Research University of York.

Methods. Elsevier Publishing, Amsterdam, pp 5-30. 17 Whittington MW, Antonio CM, Corne A. Gelt FR [19971. Technical

5 Hartnoll RG [19761. The ecology of some rocky shores in tropical Report 3: Central Islands Group - Ibo.

East Africa. Estuaries Coastal f4anne Science 4: 1-21. 18 Antonio MC. Unpublished data.

6 Gove DZ [19951. The coastal zone of Mozambique. In: Linden ledl 19 Gell FR, Whittington MW [2000]. Diversity of fishes in seagrass beds Workshop and Policy Conference on Integrated Coastal Zone in the Quinmba Archipelago, northern Mozambique. Manne and

Management in Eastern Atnca including the Island States. Freshwater Research b3: 115-121. Conference Proceedings. Coastal Management Center ICMCl, 20 Barnes DKA, Come A, Whittington M, Can/alho MA, Gell FR [19981.

Metro Manila, pp 251-273. Coastal shellfish resources use in the Quinmba Archipelago, 7 Bandeira SO [19951. Marine botanical communities in southern Mozambique. Journal of Shellfish ffesearc/i 17111: 51-58. Mozambique: Sea grass and seaweed diversity and conservation. 21 Adams JB, Bate GC, Q'Callaghan M [1999]. Estuanne primary

Ambio 24: 506-509. producers. In: Allanson BR, Baird D ledsl Estuaries of South Africa.

8 Bandeira SO, Antonio CM [19961. The intertidal distribution of Cambridge University Press, Cambridge, pp 91-118.

seagrasses and seaweeds at Mecufi Bay, northern Mozambique. In: 22 Martins ARO, Bandeira. SO [2001]. Biomass and leaf nutrients of

Kuo J, Phillips RC, Walker Dl, Kirkman H ledsl Seagrass Biology: Thalassia hemprichii a\. Inhaca island. Mozambique South African

Proceedings of an International Workshop. University of Western Journal of Botany b7:i'i')-U2.

Australia, Nedlands. pp 15-20, 23 Martins AR [1997]. Distribuicao. estrutura, dinamica da erva 9 Bandeira SO [20021. Leaf production rales Thatassodendron mannha Zostera capensis e estudo de alguns parametros fisicos

ciliatunn from rocky and sandy habitats. Aguatic Botany 11: 13-24. em duas areas da Baia de Maputo. Licenciatura thesis. Eduardo

10 Bandeira SO, Bjbrk M [20011. Seagrass research in the eastern Mondlane University, Maputo. 49 pp.

Africa region: Emphasis to diversity, ecology and ecophysiology 24 Kalk M [19951. A Natural History of Inhaca Island, Mozambique.

South African Journal of Botany 67: 420-425. Witwatersrand University Press, Johannesburg. 395 pp.

11 Barnabas AD [19911. Thalassodendron ciliafumlForsk.l den 25 de Boer WF, Longomane FA [1996]. The exploitation of intertidal

Hartog: Root structure and histochemistry in relation to apoplastic food resources at inhaca bay, Mozambique by shorebirds and

transport. Aquatic Botany kQ: 129-143. humans. Biological Conservation 78: 295-303. India

9 The seagrasses of INDIA

T.G. Jagtap

D.S. Komarpant

R. Rodrigues

has coastal wetlands of ca 63 630 km, mostly Surprisingly, seagrasses have not been introduced India consisting of estuaries, bays, lagoons, brackishi even at the level of plant science education programs.

waters, lakes and salt pans'". The intertidal and Hence, large number of students, researchers and supralittoral shallow sheltered regions of these wet- coastal zone managers in India may be unaware of the lands harbor various marine macrophytic ecosystems existence of seagrass ecosystems. Here, we present an such as seaweed, seagrass, mangrove and other obli- overall account of seagrass habitats from India. gate halophytes. Coastal wetland habitats are of a Epiphytes form an important constituent of productive nature, and are of immense ecological and seagrass ecosystems in India, though very limited socioeconomic importance. Marine macrophytes sup- information is available"'"'". The floral epiphytes port various kinds of biota, and produce a considerable comprise a few species of marine algae belonging to amount of organic matter, a major energy source in the Cyanophyceae, Chlorophyceae, Rhodophyceae and coastal marine food web; they play a significant role in Bacillariophyceae. The Rhodophyceae, particularly nutrient regeneration and shore stabilization processes. Metobesia sp., occur frequently and are a dominant

The major seagrass meadows in India exist along part of epiphytic biomass" "'. Cyanophycean members the southeast coast IGulf of Mannar and Palk Bayl and such as species of Microcoieus. Mastogocoleus and in the lagoons of islands from Lakshadweep in the Oscillatoria were observed to be dominant epiphytes.

Arabian Sea to Andaman and Nicobar in the Bay of Ten species of diatoms have been reported on seagrass

Bengal (Table 9.11. The flora comprises ^U species and blades and roots. The oldest leaves and roots were is dominated by Cymodocea rotundata, Cymodocea found to be more infested and Navicula, Nitzschia and serrulata, Thalassia hempnchii. Halodule uninervis, Pleurosigma form the characteristic diatoms assoc-

Hatodute pinifotia. Halophila beccarii, Halophila ovata iated with seagrasses" "". Large numbers of fungi have and Halophita ovalis (Table 9.21. Distribution occurs also been reported in association with seagrass""'. Nine from the intertidal zone to a maximum depth of ca species of fungi have been recorded in association with

1 5 m. Maximum growth and biomass occur in the lower Thalassia hemprichii \n India"". Microbial flora actively littoral zone to a depth of 2-2.5 m. Greatest species mineralize seagrass litter and constitute about 1-3 richness and biomass of seagrass occur mainly in open percent of detrital biomass"". The epiphytes contribute marine sandy habitats. 7.5-52 percent of total seagrass ecosystem biomass in Seagrasses, though one of a predominant and shallower (1-3 ml depths. The higher epiphytic biomass specialized group of marine flora, are poorly known in (Figure 9.1 bl results mostly from algal genera such as

India, compared to other similar ecosystems such as Metobesia, Hypnea, Ceramium and Centroceros. The mangroves. Earlier studies dealt mainly with the intensity of epiphytization increases with shoot age and distributional and taxonomic aspects of Indian decreases at depths of more than 3 m. seagrasses'^'^'. Over the last 20 years, efforts have been Epifauna mostly consist of protozoans, made to understand the community structure and nematodes, polychaetes, rotifers, tardigrades, cope- function of seagrass ecosystems in India""'". However, pods, amphipods and chironomid larvae. Very few the structure and function of Indian seagrass attempts have been made to explore the faunal ecosystems remain poorly understood"^"'. Inadequate diversity of the seagrass beds of India. Harpacticoids, information and almost total lack of awareness might nauplii and nematodes are rarely found on seagrasses be the reasons for this tack of knowledge in India. from India"'"'. WORLD ATLAS OF SEAGRASSES

Most of the algal groups In marine seagrass beds seagrass beds; however, Dugong dugon, the marine grow on coral or shell debris, and on seagrass stems mammal [dugong], has been very rarely reported In

and roots, in their earlier stages. Later stages of these recent years''"'. The fish fauna is reported to consist of algae become detached and float in the waters overlying 192 species, dominated by sardine, mullet, eel, cat- and the meadows. Some 100 species of algae have been re- parrotflshes and grouper'"'. The mollusks (U3

ported from seagrass in various regions of India (Table species), crustaceans (150 species! and echinoderms

9.31. The algal flora in general is dominated by Ulva [77 species) are also found In large numbers (Table 9.3). lactuca, Ulva fasciata. Boodles composita, Chaeto- Mollusks are mostly represented by Acanthopleura morpha linum, Halimeda spp., Chnoospora implexa, spiniger, Acniaea stellaris, Conus generalis, Cypraea Chnoospora minima, Dictyota bartayresiana, Dictyota figris and Nerita costata. There are four species of sea turtle, with Chelonia mydas and Lepidoclielys olevacea being common.

Table 9.1 The biomass and species richness of meiofauna

Quantitative data for major seagrass beds in Indian waters and macrofauna in general is relatively very high in the seagrass beds compared to unvegetated areas in the

Region No. of Biomass Area vicinity"^'. Sediment organic content from seagrass

species Ig dry weight/m'l Ikm'l beds varies from i to 13 percent, ten times higher than

Southeast coast 14 2.5-21.8 30 the sediments from unvegetated areas.

IGulf of Mannar The textural characteristics of the sediment may

and Palk Bayl be of great significance In determining density of

Lakshadweep 8 15-72 1.12 seagrass growth. Well-established seagrass meadows

group of islands influence mean size, sorting, skewness and shape of the

Nicobar group 9 - 8,3 accumulated sedimentary particles'"'. The sediments

of islands from seagrass beds of the Lakshadweep Islands show a

West coast 4 - Patchy significant correlation coefficient (r = 0.85, p<0.05) between kurtosis and total biomass, Indicating

Notes; - no data available. prevalence of a relict environment'"'. This means that the deposltlonal environment, which developed from '^°"' Source: Vanous sources'^' coral reef biota over geological time, is most suitable for seagrass growth, a concept supported by the occurrence

of major seagrass beds In association with coral reef

'^' dichotoma, Dictyota divaricata, Hydoclattirus clathratus, regions" '° '". Halophila beccarii. an estuarine sea- Gracilaria edulis, Hypnea musciformes. Amphiroa grass, acts as pioneer species in the succession process

fragillissima. Amphiroa rigida, Centroceros clavilatum leading to mangrove formation in Indla'"^". Thus, and Centroceros spp. , particularly seagrasses play a very important role as basic land

Halimeda spp., contribute substantially to the formation builders and shore stabilizers, in a similar way to sand

of sediments suitable for the growth of the seagrasses"". dunes and mangroves.

Most of the associated algal biomass contributes organic

matter to the seagrass environment. BIOGEOGRAPHY

Phytoplankton in the water column over the Seagrass habitats are mainly limited to mud flats and seagrass beds largely belong to Baclllarlophyceae and sandy regions from the lower intertidal zone to a depth

Dinoflagellata; their occurrence is mostly patchy and of ca 10-15 m along the open shores and in the lagoons the population density remains very low. The around islands"". The major seagrass meadows In

phytoplankton from the seagrass beds of Lakshadweep India occur along the southeast coast [Gulf of Mannar

was reported to comprise 13 species (Table 9.31, and Palk Bayl, and a number of islands of commonly represented by Achnanthes longipes, Lakshadweep in the Arabian Sea and of Andaman and

Asterionella japonica, Diploneis weisfloggi, Navicula Nicobar In the . The largest area [30 km')

hennedyii, Pinnularia sp., and Trichodesmium sp. of seagrass occurs along the Gulf of Mannar and Palk

Absolutely no information exists on nanoplankton and Bay, while it is estimated that ca 1.12 km' occur In the picoplankton from the seagrass environment of India. lagoons of major islands of Lakshadweep"" [Table 9.1).

The regions of India that are colonized by sea- A total 8.3 km' of seagrass cover has been reported grasses support rich and diverse fauna"" ""'. Hard from the Andaman and Nicobar Islands, a large portion

corals, sea anemones, moUusks, sea cucumbers, star- of which Is confined to islands like Teressa, Nancowry, fishes and sea urchins are common invertebrates. Katchall and Great Nicobar"" "'. Seagrasses have been

Vertebrates such as fish and turtles commonly occur In reported to occur In long or broken stretches, or small

1-^ Regional map: Africa, West and

I ^ ^^%- '. .—^' • o o CM CM :- ' .. ' • ;> ^ '-I- v^^ S; o a . • Co ^ ^ ;--'•. as a tij b Ol O •••• • E ' -. . .J- :^ ' *> X s. Q ^^'\ ^ ^--^ ® *.• • s '" o -'. /."' o CN 1 f* 3>v-. * *^ -Is "'''•. i-v^ ^ s i' g ,'\.. ; ->; V -^--"- ol1 k > . c-'t'--^ -|^^H^i^u i _ ' ^' lK5iiB- %

..; •

• " -

•• ''•^*-^ • ../' /'^"'•^-^ •- <»/;:..•' • # - b; : ••' ""i/-" -k.^ ...->•-•. j s •'•^i • f'H^

^ • / '- \ J

b V' ^ m • > ' '' ^^ VK^V ^.~- - ^.

b

•. -. ><._ — ^ ir mi E^O J^^H ^ :''^M1 J. ^Qr^^HH•. j^ -^^^^^^^^^_ b CM ^ ^^ ^^^^^^^^^^^^ P CM IV WORLD ATLAS OF SEAGRASSES

IMPACTS TO SEAGRASS ECOSYSTEMS

•% ^ ^ ,^^ 200 m ^^^^M

Patch reef in Florida lUSAI, Dark areas are seagrass meadows. Light areas around the coral heads 125-50 m diameterl are haloes created by

herbivorous fish which live in the corals and graze on the seagrass

Seagrass beds on the flats adjacent to an Indonesian community are

Epiphytic algae growing on Zostera manna, Ninigret Pond, being destroyed by boat traffic, fishing activities and waste discharge, in

Rhode Island. USA. contrast to the healthy seagrasses across the channel (lower left]. A1,

V E

India 103

70- 80* E 1 ^^^GulfofKulch A

(.«// uf

Kluiinhliiii 20- N North AndaiTur IK.IHI ,s »

1 St •.

*, INDIA Middk • .'Viidarnan • Ajldjiiiatl 1 • ^ Isbnds

* Ueilgul « 1 * •

"

1 • - , Kjiimai 1 '. HuH B„i Lakshadwecp () * // 10- N 1 Lictlc .\ndaman

/Hull ../ . SRI , 100 200 300 400 500 Kilometers

^ ^^L—^™ 1 .ISD.I Af.\.\ St A Map 9.1 Ten /)i'i,'rci' ( huniiil India

to Large patches" '°'". The maximum seagrass cover, abundance and species richness are generally found in . CarNicohar the sandy regions along the seashores, and in the lagoons of islands, where salinity of overlying w/aters remains above 33 psu throughout the year (Table 9.21. The estuaries, bays, lakes and gulf regions harbor a amorta limited number of seagrass species in the lower

nnJ N,ancowry intertidal mud flats in regions of moderate to high (10- Ci 40 psu) salinity during pre-monsoon (March-June) and Nicobar post-monsoon (November-February) periods'"'. During Islands the monsoon itself (July-October) the seagrass beds, particularly estuarine seagrasses, are subject to freshwater flooding and become silted and decay'"" {in;al Nicobar The new growth of estuarine seagrasses starts during 20 40 60 80 100 Kilometers August-September with a gradual increase in salinity, and attains maximum growth during November- Map 9.2 December, and May-June'". Andaman and Nicobar Islands

PRESENT DISTRIBUTION from Kalpeni and Kadmat Islands of Lakshadweep,

The seagrasses of India consist of H species belonging plant composition is bispecific and monospecific, to seven genera (Table 9.2). The (southeast] respectively""'. Gulf and bay estuaries mostly harbor low coast harbors all 1A species, while eight and nine numbers of species, dominated by Halophila beccani in species have been reported from the Lakshadweep and the lower intertidal regions, and by Halophila ovalis in

Andaman-Nicobar groups of islands, respectively The the lowest littoral zones. Enhalus acoroides has mainland east coast supports more species than the restricted distribution in the mid-intertidal swampy ""'. west coast of India. The main seagrasses are Thalassia regions and shallow brackish waters'^ hemprichii, Cymodocea rotundata, Cymodocea Seagrasses grow from the regularly inundated serrulata, Hatodule uninervis and Halophita ovata. intertidal zone to ca 15 m depth in the sandy subtidal

Species such as Syringodium isoetifotium zones" '"'. Unlike other species, Halophila beccarii is and Halophila spp. occur in patches as mixed found in the upper intertidal. The maximum number species. Meadows are mostly heterospecific. However, of species and highest biomass usually occur at the

¥ 104 WORLD ATLAS OF SEAGRAS5ES

depth of 1-2.5 m (Figure 9.11. The biomass of major considerable contribution to total seagrass system

seagrass beds has been reported to be significantly biomass" '"'. Biomass of Haiophila beccarii is reported

'"'. |r = -0.63 -0.71 correlated with depth" to vary from 4 to 2A wet weight/m' with a minimum in and , p<0.05l g

Thalassia hemprichii, Cymodocea rotundata, the month of August and a maximum in October'". Cymodocea serrulata and Haiophila ovata are well adapted to the poor ambient light at greater PRESENT THREATS

depths l>3 ml. The natural causes of seagrass destruction in India are Biomass of Indian seagrasses varies from 180 to cyclones, waves, intensive grazing and infestation of

720 g wet weight/m' (see also Table 9.1 1. Halodule fungi and epiphytes, as well as "die-back" disease.

uninervis and Cymodocea rotundata in the shallower Exposure at ebb tide may result in the desiccation of depths 10.5-2.5 ml, and Thalassia hemprichii and the bed. Strong waves and rapid currents generally Cymodocea serrulata from the deeper l>3 ml waters, destabilize the meadows causing fragmentation and

are the main contributors to biomass along the loss of seagrass rhizome. The decrease in salinity due

southeast coast (Figure 9.11. A similar trend of to excessive freshwater runoff also causes dis-

distribution and abundance was observed from major appearance, particularly of estuarine seagrass beds in

seagrass beds of Lakshadweep Islands in the Arabian the confluence regions.

Sea'". The lower biomass and reduced number of taxa in Anthropogenic activities such as deforestation in

seagrasses deeper than 2 m is mainly attributed to the hinterland or mangrove destruction, construction of

insufficient ambient light. The older plants provide sub- harbors or jetties, and loading and unloading of stratum for colonization by epiphytes, which make a construction material as well as anchoring and moving

Table 9.2

Occurrence of seagrasses in coastal states of India

Seagrass sp. States

West East

GJ MH G KA KL LD WB OR AP TN A&N

Cymodocea rotundata - - - - - ++++ - - - + + + + +

Cymodocea serrulata - - - - - + - - - + + + + +

Enttalus acoroides - - - - + + - - - + +++

Halodule pinifolia ------+ - + + + + +++

Halodule uninervis + - - - - +++ + - + + + + +

Halodule wrigtitii + 4. +

Haiophila beccarii +++ +++ t^ +++ - - +++ +++ ttt + + + -

Halopliila decipiens ------+ -

Haiophila ovalis + - +++ - - +++ + + + + + + + + + + + +

Haiophila ovalis Mar. ramamurtiana ------+ -

Haiophila ovata + - - - - +++ + + + + + + +++

Haiophila stipulaceae ------+ -

Syringodium isoetifolium - - - - +++ - + + + +

Thalassia hemprichii : ++++ : : +++ +++

Ruppia maritima - - - ++ - - - - - ++ + -

Total no. of species 4 1 2 2 1 8 6 3 6 14 9

Status of seagrass ecosystem D G G D MD C G G G D VG

Salinity (psul 35-40 0-33 0-33 0-33 0-33 34-36 0-31 0-33 0-33 33-35 33-35

Notes:

States: GJ ; MH Maharashtra; G Goa; KA Karnataka; KL ; LD Lakshadweep Islands WB West Bengal OR Onssa APAndhra Pradesh; |

TN Tamil Nadu; A&N Andaman and Nicobar Islands

Frequency of occurrence: - absent; + very rare; ++ rare; +++ common +++ + dominant-

Status of seagrass ecosystem VG very gooc Ggooc D degraded; MD most degraded; C in the process of formation.

'''°-'°'"' Source: Vanous sources"-

•f-^ India 105

However, seagrasses in India have been largely left out to Table 9.3 of education, research and management compared

Associated biota of seagrass beds of India other ecologically sensitive habitats such as mangroves, sand dunes and corals. Considering the lack of

Group Number of spe cies awareness, limited distribution and rising anthropo-

Fauna genic pressures, it is imperative to develop a national for Bait fishes 21 educational and conservation management plan the

Ornamental fishes 138 seagrass ecosystem with the following objectives:

Fin fishes 33 quantification, mapping and regular monitoring to

Crustaceans 150 evaluate changes over time;

Mollusl

Turtles 4 mitigation of adverse impacts; of areas as Mammals 1 identification and conservation

Flora germplasm centers;

Marine algae 100 rehabilitation.

Phytoplankton 13

Fungi 9 Figure 9.1

Abundance of seagrass species at various deptfis in the Gulf of

'' 20. 221 Source: Various sources"- Mannar Isoutheast coast!

Thalassia of boats and ships, dredging and discharge of sediments, hemprlchli land filling and untreated sewage disposal, are some of the major causes of seagrass destruction in India. As a result of the above natural and anthropogenic activities, the sediment load in the overlying waters of seagrass beds increases, reducing the amount of ambient light, resulting in lower productivity because of a decline in photosynthetic processes and increased respiration. The excess sediment input in the region results in the siltation and decline of seagrass beds. The siltation of seagrass beds has been commonly observed in the Gulf of Kutch, Gujarat, Andaman and Nicobar Islands, and in 4 5 most of the estuaries. Depth (ml

Seagrass beds in the lower intertidal region in the

Gulf of Kutch and a number of islands have experienced Figure 9.1a decline. Haiophila decipiens, reported earlier'"' along the west coast, has totally disappeared, which might be

due to its elimination during natural succession. ^ Total Overexploitation of fisheries, particularly sea cucum- r. Epiphytic bers and sea urchins, has impacted the resources ^M Seagrass associated with seagrass beds. Dugong dugon. which

was abundant five decades ago"", has totally dis- appeared along the Indian coast. The last report of dugong sightings dates back to 1994-95 in Andaman waters'"'. The loss of this mammal from the Indian coast could be attributed to overexploitation for fat and

meat, as well as the obvious declines in seagrass beds.

POLICY RESPONSES

In India, seagrass regions, along with mangroves and \ I L 0.5 1.0 1.5 2.0 3.0 4.0 5.0 10 15 corals, have been categorized as ecologically sensitive Depth Iml ecosystems under the Coastal Regulation Zone

Notification to the Environment (Protection! Act'"'. Figure 9.1b ^ 106 WORLD ATLAS OF SEAGRASSES

Case Study 9.1 KADMAT ISLAND

1°10'52"-1 Kadmat Island is located at 1 ri5'20"N fixed transects laid down from -10 m on the reef

and 72°45/ll"-72°4779"E. It stretches ca 8 km from slope up to ca 150-200 m above high-tide line on the

north to south, ranging in width from ca 50 to ca ^00 Island. The length of the transect varied from ca 1 to

m. with an area of 3.12 km^ The lagoon is on the 3.5 km depending upon the topography or the leeward Iwesternl side, with a depth of 2-3 m. The contour The samplings were done during the post- along the eastern side has an average monsoon (November 19981 and pre-monsoon (May

width of ca 100 m. A coralline algal ridge occurs 1999) seasons. The collections and observations along the breaking zone of the storm beach. The were made from depths of -10 m and -5 m on the

island IS a submarine platform with a coral reef in reef slope and from -1.5 and -2.5 m in the lagoon,

the form of an . It is crescent-shaped, having a and from exposed flats of reef and storm beach .

north-south orientation. The western margin of the The seagrass bed in Kadmat Lagoon occurs in

lagoon is a submarine bank marked by a narrow patches as well as longer stretches along the shore.

reef below. A dense meadow occurs towards the northwest

Sampling and observations occurred along five region of the lagoon covering some OAA km^ and

Cfiaracterlzation of a seagrass meadow at Kadmat Island, Lakshadweep

Period November 1998 March 1999

Zone Lagoon MId-lagoon Lagoon Lagoon MId-lagoon Lagoon

towards region towards towards region towards

fore reef land fore reef land

Deptfi Iml 1-1.5 1.5-2.5 0-0.5 1-1.5 1.5-2.5 0-0.5

Substratum StCD S S S+CD S S

Tfiickness of substratum Icml >2.5 5-10 >10 >2.5 5-10 >10 - - - Sand % (range) 97.1-97.95 97.8-98 9i.8-97.6 - - Silt % (range) 0.23-2.8 1.67-1.82 2.02-2.48 - - - Clay % (range) 0.1-2.03 0.32-0.42 0.41-2.74

Organic carbon (%) 0.11-0.27 0.21-0.23 0.36-0.42 1.08-1.4 1.52-1.96 0.92-1

Nature of seagrass beds SP LP BS SP LP BS

Quantitative aspect of seagrasses

Number of seagrass species 1 2 1 2 2 1

Thalassia hemprichii

% frequency of occurrence 10-20 10-20 A 10-20 50-70 A

Blomass Ig dry weight/m-j N 5 NA N 7.5 NA

Cymodocea rotundata - % frequency of occurrence A 10-20 50-70 50-70 >70 - Blomass (g dry welght/m'') NA 15 17 23 26

Total biomass (g dry weigtit/m') NA 20 17 N 30.5 26

Average total drifted biomass NA NA N NA NA 195

(g dry weight/m)

Notes:

- data not collected.

S sandy; CD coral debns; SP small patches; LP large patches; BS broken stretches.

A absent; N negligible. NA not applicable.

Source: Desaietal"". India 107

exhibiting marked zonation. Mostly sparse and small patches of Thalassia hemprichii occur in the shallow sandy regions towards the fore reef, while the mid- lagoon deeper region (1.5-2.5 m) harbors mixed dense beds of Thalassia hemprichii and Cymodocea rotundata. The shallow region 10.5-1.5 ml towards land supports intensive growth of Cymodocea rotundata. A similar kind of distribution trend has been reported from the other islands on the Laccadive Archipelago"™. The seagrass flora of Kadmat comprises two species with higher biomass

120-35 g dry weight/m^l occurring from the mixed zone in the mid-lagoon Isee table, left). A biomass of drifting seagrasses 1195 g dry weight/m'l was recorded during March when the biomass of the seagrass standing crop was higher 126 g dry weight/m^l. The frequency of occurrence of drifting seagrass increased from 20 percent to 70 percent during March, reflecting seagrass maximum bio- mass: It IS during this pre-monsoon period that high wind speeds cause disturbances in the state of the sea, including lagoon waters. Previously, five species of seagrasses were recorded from the lagoons of

Kadmat'^". It has been observed that the small-sized seagrasses, such as Hatophila spp,, commonly grow as pioneer species and form a suitable substratum

for other larger-sized seagrasses to follow during the Thalassia hempnctm. succession process"""'. The absence of such species from Kadmat Lagoon during this study might be due at Kadmat Island, to competition by the existing species during Bentfilc macrofauna In tfie seagrass bed succession. Lakshadweep A considerable amount of seagrass biomass Dominant contributes to the detrital food chain"". The benthic Macrofauna No. of No. of % faunal population from the seagrass beds has been group genera species composition taxa Lumbnconeries reported to be higher due to high organic carbon in Polychaeta 20 22 18.96 the sediments"^'. The organic carbon in the sedi- Syllis, Onuphis, ments, particularly from the seagrass beds, varied Polydora 18.71 - from 0.11 to T96 percent Isee table, left). Macro- Nematoda 1 40.17 - fauna from the seagrass bed of Kadmat Island Oligochaeta 1 Mesodesma, consisted of eight groups Isee table, right). Pelecypoda 3 2.96 Macrofauna were largely Oligochaeta K0.17 Donax Cenlhium, percent), but the maximum number of species 1221 8 2.32 Cerithidea were from Polychaeta group"*'. It was reported Amphipoda, earlier that Polychaeta \AA.6 percent) and Crustacea Crustacea 6

(42 percent) constitute the major macro- Isopoda 0.61 Echlurida Invertebrates in the seagrass beds of India'"'. Ophiuroidea 1 - The composition of meiofauna in seagrasses Aschelimmthes 4.47 varies seasonally"^'. The meiofauna from the Unidentified 0.44

seagrass bed of Kadmat'™ is represented by 19 groups dominated by Turbellaria 134.2 percentl, Note: - not identified to genus/species level. Nematoda 137.3 percentl and herpacticoid copepods

llO.l percent). Source- Branganza ela/."^' 108 WORLD ATLAS OF SEAGRASSES

The Ministry of Environment and Forests, laboratories to undertake investigations on the various , coordinates environment and aspects of seagrass ecosystems. biodiversity-related coastal zone management

programs in tfie country. Ttiis department has a vital ACKNOWLEDGMENTS

role in adapting and implementing educational and Ttie auttiors are grateful to tfie Director of Ifie National Institute of

management plans for the seagrass environments of Oceanography jCSIf?!, Donapaula, Goa, for tiis encouragement.

India, similar to those for mangrove and coral reef habitats. The necessary inputs based on research AUTHORS

would be of great importance in the formation of a T.G. Jagtap, D.S. Komarpant and R. Rodngues, National Institute of

national seagrass management plan. Hence, the Oceanograpfiy, Dona Paula, Goa - 403004, India. Tel: 91 101832 456700

ministry must encourage universities and national 4390. Fax: +91 10)832 456702/456703. E-mail: tanaiiScsnio.ren.nic.in

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Ahmedabad, funded by Ministry of Environment and Forests, 19 Siddique HN [19801. The ages of the storm beaches of the

Government of India, SAM/SAC/COM/SN/n/92. 100 pp. Lakshadweep iLaccadivel Marine Geology 3S: M11-M20. 2 Santapu H, Henry AN [19731. A Dictionary of the Flowering Plants 20 Das HS [19961. Status of Seagrass Habitats of Andaman and

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3 Untawale AG, Jagtap TG [19781. A new record of Halophita beccani 21 Jagtap TG, Inamdar SN [19911. Mapping of seagrass meadows from

lAschersI from Mandovi estuary, Goa. India. Mahasagar, Bulletin of the Lakshadweep Islands llndial, using aerial photographs. J Ind

the National Institute of Oceanography 10: 91-94. Soc Remote Sensing 1'):V -81.

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Proceedings. Donapaula, Goa. pp ni-lfh. 23 Swinchatt JP [19651. Significance of constituent composition,

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Seagrasses of Coromandel Coast, India. Flora of India, ser 4, BSI, sediments. Journal of Sedimentary Petrology 3b: 71-90.

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teccani (AschersI in Mandovi estuary, Goa. Indian Journal of Journal of Marine Sciences 53-59. Marine Sciences k 215-217. 25 Hacketl HE [19771. Manne algae known from Maldive Islands. Atoll

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Indian Journal of Marine Sciences 16: 56-260. Region. ICLARM, Manila, 46 pp.

8 Jagtap TG [19911. Distnbution of seagrasses along tfie Indian 27 Jagtap TG [19851. Ecological Studies in Relation to the Mangrove

Coast. Agualic Botany iO. 379-386. Environment along the Goa Coast, India PhD thesis, Shivaji

9 Jagtap TG [19961. Some guantitative aspects of structural University Kolhapur 212 pp.

components of seagrass meadows from the southeast coast of 28 Untawale AG, Jagtap TG [1991]. Flonstic composition of the deltaic

India. Botanica Marina 39: 39-45. regions of India, In: Vaidyanadhan R ledl Deltas of India,

10 Jagtap TG [19981. Structure of major seagrass beds from three Memoir 22. Publication GSI, Bangalore, pp 243-265.

coral reef of Lakshadweep, Arabian Sea, India, Aquatic 29 Jagtap TG [19921. Marine flora of Nicobar group of Islands,

Botany 60: 397-408. . Indian Journal of Marine Sciences 22: 56-58.

11 Untawale AG, Jagtap TG [19891, Marine macrophytes of 30 Parthasarthy N, Ravikumar K, Ramamurthy K [19881. Halophila

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12 Ansan ZA [1984]. Benthic macrofauna of seagrass [Thalassia dugonl. CMFWSuHehn. 42 pp.

hemprichiil bed at Minicoy, Lakshadweep. Indian Journal of Marine 32 Anon [19901, Coastal area classification and development

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13 Ansari ZA, Rivonker CV, Ramani P, Parulekar AH [1991]. Seagrass No. SC 595 IFl - Desk - 1/97.

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14 Sathe V, Raghukumar S [19911. Fungi and their biomass in detntus 34 Mann KH [1988]. Production and use of detntus in various fresh

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15 Jacobs RPWM [19821. A Report: Component Studies in Seagrass 35 Branganza C, Ingole BS, Jagtap TG. Unpublished data.

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BV.Mijderchl.pp 11-215. Distribution and diversity of manne flora in coral reef ecosystems

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and Management. CRC Press, New York. 309 pp. Atoll Research Bulletin. 17 Larkum AWD, McComb AJ, Shepherd SA [19891. Biology of

Seagrasses. Elsevier, New York. 841 pp.

-h^ Western Australia 109

10 The seagrasses of WESTERN AUSTRALIA

D.I. Walker

The coastline of Western Australia extends 12 500 almost 300 km, offshore reefs protect sandy beaches km, from tfie temperate waters of tfie Southern and high foreshore sand dunes from oceanic swell, Ocean at 35°S to the tropical waters of the Timor producing a calmer habitat between the reefs and the

Sea at 12°S, with the contiguous coastline of the shore, suitable for seagrass growth. At Twilight Cove Northern Territory extending across to Queensland. the cliffs again approach the sea and follow the

coastline to just east of Israelite Bay. From there to ECOSYSTEM DESCRIPTION Esperance, beaches and seagrass beds are sheltered

The long coastline has a diversity of environments that by the granitic islands of the Recherche Archipelago, 5- support seagrass, ranging from those tropical species 50 km offshore. associated with coral reefs and mangroves in the north From Esperance to Albany, sheltered beaches are to large temperate seagrasses, in the shelter of broken by granite outcrops although occasionally limestone reefs and in large embayments, on the west limestone reefs and eroded cliffs occur. Small rivers and south coasts. These are exposed to different tidal flow into a number of bays along this 500-km coastline, conditions (amplitudes 9 m in the north to less than 1 m but they have relatively low discharge rates, on the west and south coasts'"!, substratum types and particularly during the summer dry season. Offshore of exposure to wave energy. Although some areas of the these estuaries, seagrasses of the Posidonia Western Australian coast, such as Cockburn Sound, ostenfeldii group occur as they can withstand swell and have been the subject of much research, a great deal of sediment movement. the rest of the marine environment is poorly described From Albany to , limestone or understood. overlies granitic rocks tor much of the coast.

This chapter will provide a brief description of the Seagrasses occur in this region in sheltered inshore coastal geomorphology, seagrass species and habitats, lagoons protected by offshore reefs, and their biogeography. Current uses wiU be described , east of Cape Naturaliste, is north and current and potential threats to these habitats/ facing and the prevailing southwesterly swell is uses considered. Extensive use of Environment refracted into the relatively sheltered embayment. The Western Australia 1998: State of the Environment embayment has a thin sediment veneer (mean

Reporf and of The State of the Marine Environment thickness: 1 m) overlying Pleistocene limestone'^'. It

Report''^' has been made in compiling the latter section provides an ideal habitat for seagrasses'", and of this review. Issues of seagrass management will also extensive meadows are found to depths of 25 m. be discussed. A number of estuaries, larger than those further east, also afford habitat for seagrasses and other submerged Geonnorphology of the coast aquatic plants such as Ruppia" "' and their associated

The underlying geology of the coast consists of granitic invertebrates. rocks in the south and southwest, with extensive The western coastline, from Geographe Bay to mantling of tertiary limestone, and sandstones in the Kalbarri, is relatively straight and continuous, as it has northwest and north. In the southeast of the state, the been eroded by the action of winds and currents which vertical limestone cliffs of the southern edge of the have built up sand dunes and bars parallel to the coast.

NuUarbor Plain delimit a narrow . For There is also a fringe of limestone reefs running

-N^- WORLD ATLAS OF SEAGRASSES

parallel to the coast which are relict Pleistocene dune seagrass growth to shallow water On broad intertidal

systems composed of aeolianite; these break the Indian flats, seagrasses are restricted to those species which Ocean swells, forming relatively calm, shallow (i-10 m can tolerate high and desiccation, as well

deep) lagoons up to 10 km wide, in which the tidal as periodic freshwater inundation from rainfall.

range is small l<1 m), and the waters generally clear. The Kimberley coast Is a typical ria (drowned river These lagoons are dominated by seagrasses. valley) system, characterized by resistant basement

From Kalbarri to Steep Point Ithe most westerly rock, with faults oriented at angles to the shore,

point of the mamlandl. along Dirk Hartog Island, creating a rugged coastline. The area is subject to large

Bernier and Dome Islands and up to Quobba Point, tidal amplitudes and is remote and sparsely populated,

there are high cliffs composed of sandstone to the with little information available about the marine

south and limestone to the north. These cliffs shelter habitats. Embayments and sounds grade shorewards

Shark Bay, a large 113000 km'l, shallow, semi- into mangrove-covered tidal flats, and there are many

enclosed embayment Isee Case Study 10.11. This is an offshore islands. Extensive terracing of these expanses

area of intense carbonate sedimentation, which is of the Intertidal zone often results in seagrass,

affected by wind and tidal-driven water movement, particularly Enhalus acoroides'™'. high in the intertidal

leading to high turbidity It also has relatively low water just below the mangroves.

temperatures In winter [down to 13°C1"^ tvluch of the Kimberley landscape is of

North of Quobba Point, the Pllbara coastline has a extraordinary natural beauty, extending to Its coastal low relief with gently sloping beaches, numerous regions. With a vast land area and a small population, and many small offshore islands. Headlands the Kimberley has been, until recently, largely

are composed of Isolated patches of very hard unexplored by biologists. Its isolated coastline is

hematite-bearing quartzlte, which is more resistant to devoid of settlement along the 2 000-km stretch

erosion than the surrounding rocks. Normal erosion between Derby and Wyndham. The area is receiving processes, combined with submergence, have led to a growing attention from tourists, with Increasing broken, rough coastline. Mangroves become conspic- activity by small private boats and charter operators. uous. Coral reefs and atolls occur north of Quobba As part of the development of a marine park and

Point Inear the Tropic of Capricorn), where tropical reserve system in Western Australia, several areas are

seagrasses are found in lagoons, as well as in being considered as potential marine parks. In

mangrove swamps and around islands""'. There is a addition, some of the areas have been designated as progressive increase in tidal amplitude with decreasing potential Aboriginal reserves. These designations have latitude. Large tides affect seagrass distributions by been based on severely limited data available from the

resuspending sediments; the high turbidity limits few scientists and other people who have traveled in the area. The only substantial data on marine

organisms in the Kimberley relate to salt water

Table 10.1 crocodile populations and turtles. Ivlanne plants, fish Western Australian endemic seagrass species and invertebrates are largely unknown. Recent surveys

by the West Australian Ivjuseum, the University of Species Distribution Western Australia and the Northern Territory Museum, and by CSIRO (Australia's Commonwealth Scientific

Amphibolis antardica Soutfiern Australian endemic and Industrial Research Organisation), have yet to be

Amphibolis gnffithii Soutfiern Australian endemic published, but will help provide a basis for future

Cymodocea angustata Tropical Western Australian research. endemic

Thalassodendron pachyrhizum Southern Australian endennic | BIOGEOGRAPHY

Hydrocharitaceae Seagrasses recorded from Western Australia fall Into Halophila australis Australian endemic two general distribution patterns. Twelve species are

Posldonlaceae endemic to Western Australia or to the southern

Posidonia angustifolia Soutfiern Australian endemic Australian coast, and are confined to temperate, clear Posidonia australis Southern Australian endemic waters (Table 10.1). Twelve species are tropical and Posidonia conacea Western Australian endemic are found throughout the Indian Ocean and tropical

Posidonia denhartogii Southern Australian endemic .

Posidonia kirkmanii Western Australian endemic Australia's seagrasses can be divided Into Posidonia ostenfeldii Western Australian endemic temperate and tropical distributions, with Shark Bay on Posidonia sinuosa Southern Australian endemic the west coast and Moreton Bay on the east coast being located at the center of the overlap zones. Temperate

.Jy '

Western Australia

species have been studied most extensively, 200 JOO 600 Kilometers particularly the large genera Amphibolis, Posidonia and Zostera. but there are other species which have been little studied. Temperate species are distributed * Wyndhait' across the southern half of the , extending northwards on both the east and west coasts. The Rowley 4 Derby highest biomasses. and highest regional species diversity, occur in southwestern Australia, where Montcbcllo Is.

Harrow I , • seagrasses are found in the coastal back-reef Northern Ningatoo ^ Territory environments within the fringing limestone reef, or in Marine Park, :{$ semi-enclosed embayments.

In areas of northern Australia with a high tidal range, visibility is often poor, and conventional remote- Western Australia sensing techniques are of limited value for mapping.

The Northern Territory coastline is largely unexplored for seagrass distribution, and their associated animal South Austr^la communities, especially the Northern Territory prawn fisheries, remain largely unstudied. Recent research in the Kimberley region of Western Australia has provided Perth some distribution information. Seagrasses in that litoipiiithc Bin [ ^ Esparance ,. iBunbury y- Cape Naturalisle,, , ,— region either occur sparsely in coral reef environments •w-- hraeliw/.v I

Cape Leeuwnn ,« Recherche or can attain high biomasses within high intertidal Archipcbgo fnw/mo,.! Bo, ' lagoons, where seawater is ponded during the falling / -,,,.„„.„ ^,„„, Hurboin- Mhwn tliirhoiir nintOvslfr Uiiritoiir tide"". The environments are otherwise too extreme 110" E 120'_E _JUMl_

(tidal movements/turbidity/freshwater runoff in the wet Map 10.1 season) for seagrass survival"''. Again, the significance Western Australia of these seagrass communities for any associated fisheries species is unknown. water bodies exposed to relatively high rates of water In general, our knowledge of shallow water movement. Nevertheless, Australian species also

(<10 ml temperate seagrass distributions is reasonably occur where there is some protection from extreme good, but our understanding of deep water |>20 ml water movement and most are found in habitats with seagrasses throughout Australia is rudimentary. Areas extensive shallow sedimentary environments, shel- subject to more extreme water movement, either tidal tered from the swell of the open ocean, such as or wave induced, are also poorly studied compared with embayments (e.g. Shark Bay and Cockburn Soundl, seagrasses in more protected areas. protected bays (e.g. Geographe Bay and Frenchman's

The main habitats for seagrasses are very Bayl and lagoons sheltered by fringing reefs (e.g. the extensive shallow sedimentary environments that are western coast from 33° to 25°S|. sheltered from oceanic swell, such as embayments

(e.g. Shark Bay, Cockburn Soundl, protected bays (e.g. MECHANISMS OF SEAGRASS DECLINE IN WESTERN Geographe Bay, Frenchman's Bay] and lagoons AUSTRALIA enclosed by fringing reefs (e.g. Bunbury to Kalbarri). Seagrass declines have been well documented from

Seagrasses occupy approximately 20000 km' on the around Australia. There are a variety of mechanisms of

Western Australian coast""", ranging in depth from the seagrass loss, but the most ubiquitous and pervasive intertidal to A5 m"", making up a major component of cause of decline is the reduction of light availability. nearshore ecosystems. The diversity of seagrass Seagrasses are rather unique plants in that they have genera (101 and species (251 along this coastline is high minimum light requirements for survival unequaled elsewhere in the world""', mainly due to the compared with other plants"". These high minimum overlap between tropical and temperate biogeographic light requirements (10-30 percent incident lightl are zones, and the extent of suitable habitats. hypothesized to be related to the significant portions of

Large, mainly monospecific meadows of seagrass biomass that can be in anoxic sediments. southern Australian endemic species form about one Reduction in light availability can occur as a result of third of the habitat in the coastal regions of Western three major factors: chronic increases in dissolved

Australia. These meadows have high biomasses nutrient availability leading to proliferation of light- (500-1000 g/m'l and high productivities (>1 000 absorbing algae, either phytoplankton, macroalgae or g/mVyearl"^'. Southern Australian seagrasses occur in algal epiphytes on seagrass leaves and stems; chronic WORLD ATLAS OF SEAGRASSES

Habitat removal

Coastal development In Western Australia Is localized to centers of population, and takes the form of construction of ports, nnarinas and . Housing developments impact on coastal water quality, whereas

canal estates, such as In Carnarvon, have greater direct Impact on the marine environment. All these develop- ments have potential consequences for seagrass habitats and associated fauna.

Some developments have resulted in direct destruction of seagrass communities, by smothering or

deterioration in water quality, e.g. construction of the causeway at the southern end of Cockburn Sound"", where construction destroyed existing reef environ-

ments, and resulted in loss of seagrass habitat due to

reduced flushing. The construction of ports and

mannas in the Perth Metropolitan area has degraded existing seagrass and reef habitats, as well as fragmenting the remaining distributions. Subsequent

dredging and sediment infill has often reduced the

water quality and resulted in further losses.

Impacts of pollution

Pollution of coastal environments can result In major

changes to water quality, either from point or diffuse sources which can influence marine community

structure, especially in relation to seagrass. Marine disposal of sewage from the Perth Metropolitan

region's three outfalls contributes excess nutrients to

coastal areas'"'. The Kwinana Industrial Strip along the

shores of Cockburn Sound still relies on marine disposal of the industries' effluents, although now

Intertidal Enhalus acoroides. Leonie Island, Kimberley, Western under license conditions to regulate the amounts of

Australia. toxicants.

Increases In suspended sediments leading to Increased Water quality, especially nutrients

turbidity; and pulsed increases in suspended The Western Australian coastal environment Is sediments and/or phytoplankton that cause a dramatic particularly sensitive to nutrient enrichment from reduction of light penetration for a limited time period. human activities. The effects of this anthropogenic

eutrophlcatlon include an increase in frequency,

Loss of fiabitat duration and extent of phytoplankton and macroalgal

Seagrasses are limited to the photic zone, extending up blooms''", low oxygen concentrations in the water

to 54 m"". Reductions in water quality can lead to a column, shifts In species composition'""', loss of

reduction In the depth of the photic zone""', and hence seagrass and benthic vegetation""', decrease in

to a direct loss of habitat. Seagrasses In Cockburn diversity of organisms present""' and an Increase In

Sound, for example, are limited to a depth of less than diseases In fish and waterfowl. Western Australian

9 m, whereas In unpolluted areas the depth limit would marine waters are generally low in nutrients and

be 11-15 m. Increasing population pressure In Western biological productivity. Serious seagrass losses Australia leads to Increasing pressure on the coast. resulting from Increased nutrient loading have

Development of the coastal zone, all along the Western occurred in the Albany Harbours, Cockburn Sound and

Australian coastline. In the form of construction of parts of Geographe Bay. Cockburn Sound is the most

marinas, port facilities and canal estates, results in degraded marine environment in Western Australia, degradation of coastline causing direct destruction of having experienced the second largest loss of seagrass

seagrass communities as well as Indirect changes in in Australia (more than two thirds)'^'.

hydrodynamics and sedimentation. The major human-induced declines of seagrass

\

I Western Australia 113

in Western Australia are summarized in Table 10.2, with genera Ulva, Enteromorpha, Ectocarpus] which may suggested principal causes - in most cases, other originate as attached epiphytes''*'. Increased epiphytic factors interact to make the process of loss more growth results In shading of seagrass leaves by up to 65 complex. The general hypothesis for all these instances percent''", reduced photosynthesis and hence leaf of seagrass decline is that a decrease in the light densities"". In addition, the epiphytes reduce diffusion reaching seagrass chloroplasts reduces effective of gases and nutrients to seagrass leaves. seagrass photosynthesis. The decrease may result from increased turbidity from particulates in the water, Light penetration or from the deposition of silt or the growth of epiphytes As photosynthetically active radiation passes through on leaf surfaces or stems"". Seagrass meadows occur water. It is attenuated by both absorption and between an upper limit imposed by exposure to scattering. Attenuation is Increased by the presence of desiccation or wave energy, and a lower limit imposed suspended organic matter le.g. phytoplankton] and by penetration of light at an intensity sufficient for net inorganic matter, particularly In eutrophic systems photosynthesis. A small reduction in light penetration when phytoplankton concentrations are high"", thus through the water will therefore reduce the depth range reducing light penetrating to benthic primary of seagrass meadows, while particulates on leaves producers. In Cockburn Sound, where this continued could eliminate meadows over extensive areas of for extended periods of time, reduction In density and shallower water le.g. Princess Royal Harbour, Western loss of benthic macrophytes resulted'""'.

Australial'""'. The requirement of light by benthic macrophytes

Increasing turbidity of water above seagrasses makes the presence of submerged aquatic vegetation may occur directly, by discharge or resuspension of fine an Indicator of water quality (adequate light penetra- material in the water column from, for example, sludge tion! and hence, nutrient status li.e. low nutrient dumping. Indirect effects on attenuation coefficients concentrations!'"". Light reduction for extended occur through Increased nutrient concentrations periods, which is common In eutrophic systems, causes resulting from the discharge of sewage and Industrial loss of benthic macrophyte biomass''". wastes, or from agricultural activity In catchments, which In turn Increase phytoplankton biomass reducing Siltation light penetration significantly'" ^". The extent cf phyto- Changes in landuse practices often result in Increased plankton blooms associated with nutrient enrichment sediments In runoff from land, e.g. in Oyster Harbour will be determined by water movement, and mixing will Larger sediment loads reduce light penetration, as dilute nutrient concentrations. Deeper seagrass beds detailed above. Increased sedimentation can result in further from the sources of contamination may show no changes in the abundance and percentage cover of influence of turbidity. seagrass due to increased sediment deposition or scour'™. Epiphytes

In Cockburn Sound, nutrient enrichment has led not Toxic chennicals only to enhanced phytoplankton growth but also to In general the Western Australian coastal environment enhanced growth of macroscopic and microscopic is not subjected to large-scale inflows of toxic algae on leaf surfaces'"'. Macroalgae dominate over chemicals. The 1998 Western Australian State of the seagrasses under conditions of marked eutrophlcatlon, Environment Report does not consider them a threat'". both as epiphytes and as loose-lying species le.g. the Awareness of toxic, human-produced chemicals and

Table 10.2

Summary of major human-Induced declines of seagrass In Western Australia

Place Seagrass community Extent of loss Cause

Cockburn Sound, Posidonia sinuosa 7.2 l

Western Australia Posidonia australis two thirds!

Princess Royal and Oyster Harbours, Posidonia australis 8.1 km^ lost K6%l Decreased light, increased epiphyte

Western Australia Amptiibolis antarctica and algal loads

Source: CoclV"- 11A WORLD ATLAS OF SEAGRASSES

million metric tons of ballast water are discharged into this region's marine waters each year. Currently, controls are only voluntary. Introduced marine species may threaten native marine flora and fauna and human

uses of marine resources such as fishing and

aquaculture. Knowledge of species introduced and

their distribution has recently been updated. The risk of

damage to marine biodiversity is largely unknown but international experience suggests that the potential for

significant environmental impact is high'".

Displacement of existing flora and fauna by introduced species, intentional or accidental, has been widely reported elsewhere'^". The 1998 Western Australian Sfafe of the Environment Report estimated that over 27 exotic

species have been introduced to Western Australia'".

Twenty-one of these are known to have been introduced into Perth Metropolitan waters, the most highly visible being a large polychaete worm Sabelia spallanzani

ISabellidae family!. This worm occupied up to 20 ha of

the seafloor and most of the structures in Cockburn Sound, outcompeting the native Posidonia species, but

Underwater meadow of Posidonia australis abutting a limestone its incidence has been declining"^'.

reef. , Western Australia. ESTIMATE OF PRESENT COVERAGE their impacts on marine organisms has increased, and Large, mainly monospecific meadows of southern such industrial inflows are controlled by Licence Australian endemic species form about one third of the

Conditions from the Western Australia Department of habitat in the coastal regions of Western Australia and Environmental Protection. Urban runoff may include amount to some 20000 km'. The tropical species are

such chemicals, but in Western Australia the runoff is less abundant but add a further 5000 km'. separated from the sewage system. Some direct runoff

may still influence groundwater or the coastal THREATS

environment, and increasing population pressure will Human utilization of seagrass in Western Australia is

result in increased risk of contamination. relatively restricted. Few commercial and recreational

Fortunately, the aquaculture industry in Western species are taken from seagrass habitats. According to

Australia has avoided the use of antibiotics in fish the 1998 Western Australian State of ttie Environment

foodstuffs. The potential effects of antibiotics'^' ^*'' may Report', human activities most affecting coastal

result in widespread changes in microbial activities, seagrass habitats in Western Australia are: with consequences up the food web, as well as for direct physical damage caused by port and

nutrient recycling in coastal sediments. industrial development, pipelines, communi-

The effects of antifouling compounds are also a cation cables, mining and dredging, mostly in the concern. Tributyltin ITBTI has been recorded from Perth Metropolitan and Pilbara marine regions;

Western Australian locations'"', highest near marinas excessive loads of nutrients, causing seagrass

and ports. TBT contamination is present at various overgrowth and smothering by epiphytes, from

levels in all major ports in Western Australia. TBT industrial, domestic and agricultural sources,

contamination is widespread throughout Perth mostly in the Lower West Coast, Perth Metro- Metropolitan marine environment'". The use of TBT has politan and South West Coast marine regions;

been banned in Western Australia on vessels longer land-based activity associated with ports,

than 25 m. industry, aquaculture and farming, mostly in the Pilbara, Central West Coast, Lower West Coast, Introduction of exotic (alien) species Perth Metropolitan and South West Coast marine

Exotic marine organisms have been introduced to regions; Western Australia via ballast water and hull fouling direct physical damage caused by recreational from shipping, and threaten natural distributions of and commercial boating activities including

organisms, including seagrass. It is estimated that 100 anchor and trawling damage, mostly in the Western Australia 115

Kimberley. Pilbara. Shark Bay, Perth Metro- estuaries. Nutrient enrichment of some Western

politan and Geographe Bay areas. Trawling nets Australian estuaries continues to be a problem. The

remove sponges and other attached organisms introduction of exotic marine organisms from ballast

from the seafloor. water and via the aquarium industry remains an area

of concern.

The marine environment receives most of the surface water from land. The quality of this water is SEAGRASS MANAGEMENT affected by activities and the environment of the Protected areas catchments through which it flows. Soil and nutrients All the marine parks in Western Australia contain can be carried by river discharges to coastal waters, significant seagrass habitats. In particular the Shark causing water quality deterioration. Groundwater can Bay World Heritage Property (see Case Study 10.11 also carry terrestrial pollution into the marine contains more than U 000 km' of seagrass beds of high environment. Direct discharges such as sewage and/or diversity'", as well as a population of more than 10 000 treated wastewater and industrial outfalls, and dugong, and turtles. accidental discharges such as spills and shipping Two marine parks in the Perth area, Marmion and accidents, also influence coastal water quality'". Shoalwater Islands, contain about 20 percent seagrass. These land-based activities, their impacts on The Swan River has small sections of marine park, ground and surface water and the ultimate movement mainly declared for their migratory bird populations but of these waters into nearshore marine environments also including areas of the paddleweed, Haiophlla are the major human influence on the Western ovalis. Two coral reef areas to the north of Western

Australian coast. They result in most pollution of the Australia, Ningaloo and Rowley Shoals Marine Parks, marine environment and the resulting chronic contain small but relatively diverse seagrass degradation of marine habitat. Degradation of the populations'"". Three areas to be declared as marine marine environment leads to reductions in the area of seagrass, as well as corals and mangroves. Growing land- and marine-based tourism development in Western Australia and the central- ization of population growth will cause these impacts to increase unless adequate protection and management of the coast occurs.

Fisheries innpacts

Most fishing methods in Western Australia are suggested to have a limited effect on the shallow coastal environments where seagrasses occur'". Methods that may significantly affect the environment, for example dredging and pelagic drift gill-netting, are banned. Other methods, such as trawling, that alter the benthic environment are restricted to prescribed areas.

Currently, many of these impacts cannot be quantified'^', but current assessments of the sustainability of fisheries practices suggest that damage to seagrass beds is minimal. At present there are fewer than 100 trawlers operating in a series of discrete managed fisheries Divers airlifting sediment samples from a Posidonm sinuosa within the total Western Australian fishing fleet of meadow. Princess Royal Harbour, Western Australia. around 2000. The number of these trawl licenses will be reduced over time. Areas available to trawling within parks. Jurien Bay, Cape Leeuwin-Cape Naturaliste and each trawl fishery management area are also restric- Montebellos-Barrow Island, also have diverse seagrass ted. There are significant demersal gill-netting closures ecosystems represented. in areas of high abundance of vulnerable species such The establishment of the West Australian Marine as dugong (for example, Shark Bay and Ningaloo Reefl. Parks and Reserves Authority, in which marine

Pollution, loss of habitat, sedimentation from conservation reserves are vested, should help facilitate dredge spoil and agricultural runoff can impact heavily the development of a comprehensive series of on fish stocks, primarily in nearshore waters and reserves. This process is, however, slow, and current 116 WORLD ATLAS OF SEAGRASSES

Case Study 10.1 SHARK BAY, WESTERN AUSTRALIA: HOW SEAGRASS SHAPED AN ECOSYSTEM

Shark Bay is a large 113000 km'l. shallow l<15 ml, Although the area also has terrestrial hypersaline environment, dominated by seagrasses. significance, and is home to dolphins, the world's Situated on the West Australian coastline, at about largest stable population of dugongs and living

26°S. it contains the largest reported seagrass stromatolites, the seagrasses are responsible for meadows as well as the most species-rich seagrass some of the most impressive illustrations in the

assemblages. Shark Bay is also a World Heritage world of the interaction between seagrasses and

Property, one of only 1 1 World Heritage sites in the their environment. Shark Bay provides an out-

world to have been listed under all four categories standing example of the role that seagrasses can

for nomination: play in influencing the physical, chemical and outstanding examples representing the major biological evolution of a marine environment.

stages of the Earth's evolutionary history; outstanding examples representing significant DESCRIPTION OF SHARK BAY

ongoing geological processes, biological Shark Bay is a semi-enclosed basin, with restricted evolution and humans' interaction with their exchange with the Indian Ocean, situated in an arid natural environment; landscape where evaporation exceeds precipitation superlative natural phenomena, formations or by a factor of ten. There are two gulfs, the eastern features, for instance outstanding examples of and western, formed by pleistocene dunes, creating the most important ecosystems, areas of a series of inlets and basins. Astronomical tides are

exceptional natural beauty or exceptional less than 1 m. thus atmospheric conditions influence

combinations of natural and cultural water levels. In summer, strong southerly winds elements; transport about 1-1.5 m of water northwards out of the most important and significant natural the bay. exposing sand flats up to 2 km wide. There is habitats where threatened species of animals a well-developed salinity gradient developed as the

or plants of outstanding universal value still marine waters cross the shallow carbonate banks of

survive. the Faure Sill. Salinities in Hamelin Pool may reach

issues such as extensive plans for aquaculture wilt take a long-term commitment to fund these developments being implemented by another section multidisciplinary studies.

of government IFisheriesI may compromise the A more coherent approach to managing the

effectiveness of the Parks Authority. The development marine environment is required by government

of marine conservation reserves within Western agencies. Some 15 different government agencies have Australia must form part of the framework being some responsibility for management of the Western

developed federally for Australia, and it must be Australian marine environment. The 1998 State of the

assessed to see if it provides the necessary Environment Report" recommends that the state comprehensiveness, adequacy and representativeness government should establish a formal framework to

for marine conservation to be effective. coordinate environmental management within Perth's Metropolitan marine region and between these waters Policy and their land catchments. This should be used as a On an urgent basis, more detailed studies of the pilot program for expansion to other areas under

Western Australian marine environment are required if pressure from domestic and rural discharges.

a sound basis for management is to be developed, both A recent change in state government in Western within the marine park and reserve system and outside Australia has seen major changes to the structure of

it. There have been tew coherent, broad-based studies government departments that may alleviate some of

(both in time and space! that have researched the the previous problems.

cumulative impact of pollution. siUation, habitat

fragmentation and introductions of invasive species on AUTHOR

the community structure of marine communities'^'. Diana Walker. Sctiool of Plant Biology. University of Western Australia.

Further effort is needed on the influence of these WA 6907, Australia. Tel: t61 1018 9380 2089/22U. Fax: +61 10189380 1001.

human activities on the whole community, although it E-mail: diwalkerOcyllene.uwa.edu.au

rt~r--jj'. 1

Western Australia 117

70 psu. Strong tidal currents, up to 8 knots, flow banks under the seagrass, forming the Faure SiU, as

through channels in the Faure Sill. well as the extensive sand flats.

Seagrasses, particularly the southern The build-up of the banks underlying the

Australian endemic species seagrass, in turn, has restricted the circulation of and Posidonia australis. dominate the subtidal oceanic seawater, which with high evaporation and

environment, to depths of about 12 m. The intertidal low rainfall results in the hypersalinity gradient in

flats are composed of mixed Halophila ovalis and the inner reaches of the bay. This makes the

Halodule uninervis. The 12 species of seagrass in southern areas of Hamelin Pool unsuitable for

Shark Bay make it one of the most diverse seagrass seagrasses, but has allowed the development of

assemblages in the world. Seagrass covers more stromatolites. than 4000 km' of the bay, about 25 percent, with the

1 030-km^ Wooramel Seagrass Bank being the HIGH RATES OF PRODUCTION

largest structure of its type in the world. The waters flowing over the seagrasses are

depleted in phosphorus by the seagrasses them- A STABILIZING ROLE selves. For Shark Bay as a whole, the seagrass The presence of extensive, monospecific beds of meadows represent an enormous pool, with some

these large, lengthy 12 ml seagrasses. baffle the 86 million kg of nitrogen and 6 million kg of

currents and modify the sediments underlying the phosphorus being required to support the seagrass seagrass. The plants trap and bind the sediments growth. Only about 10 percent of this can be accreting from calcareous epiphytes and associated supplied from the oceanic inflow, so the high rates

epifauna. The plants can significantly slow the rate of production must be supported by tight recycling,

of water movement over the bottom, and stabilize both from decomposition in situ and from internal the otherwise unstable sediments. Rates of retranslocation.

sediment accretion associated with Amphibolis Seagrasses in Shark Bay thus represent "an antarctica are higher than those associated with outstanding example representing significant on-

coral reefs. This is related to high rates of leaf going geological processes, and biological evolu-

turnover, depositing more calcareous sed'ments. tion", demonstrating how important seagrasses are

Over geological time, this had led to the build-up of throughout the world.

REFERENCES Seagrasses: A Treatise on ttie Biology of Seagrasses witti Special

1 Anon [19941. Australian National Tide Tables 1995. Australian Reference to ttie Australian Region. Elsevier/, 182-210. Government Publishing Service, Canberra. 256 pp. Amsterdom. pp

2 Anon [19981. Environment Western Australia 1998: State of ttie 10 Walker Dl, Pnnce RIT [19871. Distnbution and biogeography of

Environment Report. Department of Environmental Protection, seagrass species on the north-west coast of Australia. Aquatic 19-32. Western Australia. 135 pp. Botany 29:

3 Zann LP, Kailola P ledsl [1 995]. Ttie State of ttie Marine 1 Walker Dl [19971. Manne Biological Suniey of the Central Australia. Environment Report. Technical Annex I. The Manne Environment. Kimberley, Western Report to the National Estates

4 Zann LP [19961. Ttie State of ttie Marine Environment Report for Committee. 159 pp.

Australia. Technical Summary. Department of Environment, Sport 12 Dennison WC, Kirkman H [19961. Seagrass survival model. In: Kuo

Phillips Dl, and Territones, Commonwealth oi Australia. 515 pp. JJS, R, Walker Kirkman H ledsl Seagrass Biology:

5 Searle JD, Logan BW [19781. A Report on Sedimentation in Proceedings of an International Workstiop. Rottnest Island,

Geographe Bay. Research Project R T 2595. Department of Geology, Western Australia, 25-29tti January 1996. Faculty of Science,

University of Western Australia. Report to Public Works University of Western Australia, Perth, pp 341 -344. H, Dl [1989]. Australian seagrass. Department, Western Australia. 72 pp. 13 Kirkman Walker Western In:

6 McMahon K, Young E, Montgomery S, Cosgrove J, Wilshaw J, Larkum AWD, McComb AJ, Shepherd SA ledsl Biology of

Walker Dl [19971. Status of a shallow seagrass system, Geographe Seagrasses: A Treatise on Itie Biology of Seagrasses witti Special

Bay, south-western Australia. Journal of ttie Royal Society of Reference to ttie Australian Region. Elsevier/North Holland,

Western Australia 80: 255-262. Amsterdam, pp 157-181.

7 Congdon RA, McComb AJ [19791. Productivity of Ruppia: Seasonal 14 Cambridge ML [19801. Ecological Studies on Seagrass of South

changes and dependence on light in an Australian estuary. Aquatic Western Australia with particular reference to Cockburn Sound.

eoOny 6: 121-132. PhD thesis. University of Western Australia, Perth. 326 pp.

8 Carruthers TJB, Walker DL Kendnck GA [19991. Abundance of 15 Hillman K, Walker Dl, McComb AJ, Larkum AWD [1989].

Ruppia megacarpa Mason in a seasonally variable estuary. Productivity and nutnent limitation. In: Larkum AWD, McComb AJ, Estuarine Coastal and Stielf Science iS: m-W. Shepherd SA ledsl Seagrasses: A Treatise on the Biology of

9 Walker Dl [19891. Seagrass in Shark Bay - the foundations of an Seagrasses with Special Reference to the Australian Region.

ecosystem. In: Larkum AWD, McComb AJ, Shepherd SA ledsl Elsevier/North Holland, Amsterdam, pp 635-685. :

118 WORLD ATLAS OF SEAGRASSES

16 Dennison WC, Orth RJ, Moore KA, Stevenson JC, Carter V, Dollar S. 27 Wells FE, Walker Dl, Hutchings PA [1991]. Seagrass, sediment and - Bergstrom PW, Batiuk RA [1 9931. Assessing water quality with infauna a comparison of Posidonia austrahs, Posidonia sinuosa submersed aquatic vegetation. Bioscience i3: 86-9/i. and Amphibolis antarctica in Princess Royal Harbour. South-

17 Kirk JTO [1994]. Light and Photosynthesis in Aquatic Ecosystems. western Australia III. Consequences of seagrass loss. In: Wells FE.

Cambridge University Press, Cambridge. Walker 01. Kirkman H, Lethbridge R ledsl Proceedings of the 3rd

18 Walker Dl, McComb AJ [1992]. Seagrass degradation in Australian International Marine Biological Workshop: The Flora and Fauna of

coastal waters Marine Pollution Bulletin 25: 191-195, Albany, Western Austraha. Vol 2. Western Australian Museum, pp

19 Cambridge ML, Chiffings AW, Briitan C, Moore L. McComb AJ 635-639.

[1986], The loss of seagrass in Cockburn Sound, Western Australia. 28 Chiffings AW, McComb AJ [1981], Boundaries in phytoplankton

II. Possible causes of seagrass decline. Aquatic Botany 24: 269-285- populations. Proceedings of the Ecological Society of Austraha 1 1

20 Lord DA [1 994]. Coastal eutrophication: Prevention is better than 27-38.

cure. The Perth Coastal Water Study t,b: 22-27. 29 Silberstein K, Chiffings AW, McComb AJ [1986]. The loss of

21 Lukatelich RJ, McComb AJ [1989]. Seasonal Changes in seagrass in Cockburn Sound. Western Australia. III. The effect of

Macrophyte Abundance and Composition in a Shallow epiphytes on productivity of Posidonia austrahs Hook, f. Aquatic Southwestern Australian Estuanne System. Waterways Botany 24: 355-371 Commission. Perth. Western Australia. 30 Kendrick GA [1991], Recruitment of coralline crusts and

22 Lukatelich RJ, McComb AJ [19861. Distribution and abundance of filamentous turf algae in the Galapagos archipelago: Effect of

benthic microalgae in a shallow southwestern Australian estuarine stimulated scour, erosion and accretion. Journal of Experimental

system. Marine Ecology Progress Series 27: 287-297. Marine Biology and Ecology 147: 47-63.

23 Lavery PS, Lukatelich RJ, McComb AJ [1991]. Changes in the 31 Coyne R. Hiney M, O'Connor B, Kerry J, Cazabon D. Smith P [1994].

biomass and species composition of macroalgae in a eutrophic Concentration and persistence of oxytetracycline in sediments

estuary. Estuarine Coastal and Shetl Science 22: 1-22. under a marine salmon farm. Aquaculture 12311-21: 31-42.

24 McMahon K, Walker Dl [19981. Fate of seasonal, terrestrial nutrient 32 Kerry J, Hiney M. Coyne R, Cazabon D. Nicgabhainn S, Smith P

inputs to a shallow seagrass dominated embayment. Estuanne [1994]. Frequency and distribution of resistance to oxytetracycline

Coastal and Shelf Science hb: 15-25. m micro-organisms isolated from marine fish farm sediments

25 Bastyan G [1986]. Distnbuhon ofSeagrasses in Princess Royal following therapeutic use of oxytetracycline. Aquaculture 123(1-2]: Harbour and Oyster Harbour on the Southern Coast ol Western 43-54.

in Journal Australia. Technical Series 1 . Department of Conservation and 33 Kohn AJ, Almasi KN [1993]. Imposex Australian Conus.

Environment, Perth. Western Australia 50 pp. of Marine Biology Association UK 73: 241-244.

26 Walker Dl, Hutchings PA. Wells FE [1991], Seagrass. sediment and 34 Sindermann CJ [1991]. Case histories ol effects of transfers and

infauna - a comparison of Posidonia australis, Posidonia sinuosa introductions on marine resources - Introduction. Journal du and Amphibolis antarctica, Princess Royal Harbour. South-Western Conseif 47: 377-378.

Australia I. Seagrass biomass. productivity and contribution to 35 Chaplin G. Evans DR [1995]. The Status of the Introduced Marine

sediments. In: Wells FE, Walker Dl. Kirkman H. Lethbridge R leds] Fanworm Sabella spallanzanii m Western Australia: A Preliminary

Proceedings of the 3rd International Marine Biological Workst]op: Investigation. Technical Report 2. Centre for Research on

The Flora and Fauna of Albany, Western Australia. Vol 2. Western Introduced Marine Pests, Division of Fisheries, Hobart, .

Australia Museum, pp 597-610. 34 pp. Regional map: Australasia

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t. ••• » '/• b s g § A VI WORLD ATLAS OF SEAGRASSES

SEAGRASS ECOSYSTEMS

A manatee [Tnchechus manatus], ieixe-boi in Portugese

over a Halodule wrightii bed m Recife, Brazil,

A sea horse. Hippocampus whitei. amongst Zostera capncorni in Sydney

Harbour. Australia

Mediterranean Posidonia oceanica seagrass beds with

saupe ISarpa sarpa] and bream IDiplodus spp.l

Snails grazing epiphytes en Zostera Sea star in Enhalus acoroides and

manna blades in southern Norway Thalassia hempnchii. Micronesia.

Dungeness crab in Zostera King helmet in Thalassia

manna. Puget Sound. USA. (estud/num.Turks & Caicos. Lizard fish in Amphibolis antarctica. Western Australia

// Eastern Australia 119

1 1 The seagrasses of EASTERN AUSTRALIA

R. Coles

L. McKenzie

S. Campbell

Seagrass meadows are a prominent feature of the sheltered estuaries and bays. AmphihoUs is an eastern Australian coastline which extends from Australian endemic. They possibly had a much wider

the tropics (10°S) to the cool temperate zone distribution in the early Paleocene \bh million years agol (4i°Sl and includes the Great Barrier Reef World with rapid climatic and tectonic changes since that time

Heritage Area. The area includes the restricting their distribution to southern Australia'".

to the north and around the coastline of Australia to Posidonia has a fractured distribution at the present Tasmania and to Spencer Gulf. There are extensive time (southern Australia and the Mediterranean], also

seagrass habitats in this region including tropical and likely to be the result of localized extinctions in the

temperate seagrass assemblages. An overlap between past'". The genus Zostera has both temperate and these two zones occurs in Ivloreton Bay, southern tropical species in Australia.

Queensland'", Both tropical and temperate species in The tropical meadows are highly diverse, but

Australia are mostly found growing in water less than 10 generally have lower biomass than those in temperate

m below mean sea level'^'. Some species of tropical parts. While bays such as Hervey Bay and Moreton Bay

Haiophila can be found to depths of 60 m'^'. have large areas of seagrass, most tropical seagrasses

The eastern Australian coast includes areas of are found in the intertidal or shallow subtidal environ-

diverse physical characteristics. The tropical north ments of the Gulf of Carpentaria and the central and coast and Gulf of Carpentaria are monsoon influenced, southern Great Barrier Reef World Heritage Area

mostly with muddy sediments, low human population lagoon with extension into deeper waters in the central and low levels of disturbance. The tropical and most of and northern sections. the temperate subtropical Queensland east coast is The importance of seagrass meadows as struc- sheltered by the Great Barrier Reef and is effectively a tural components of coastal ecosystems has resulted

long lagoon. The temperate east and south coasts are in research interest being focused on the biology and sandier and more exposed and include the large |by ecology of seagrasses and on the methods for mapping,

Australian standards) population centers of Brisbane, monitoring and protection of critical seagrass habitats.

Sydney, Ivlelbourne and Adelaide with a standard suite Seagrasses of eastern Australia are important for of associated anthropogenic coastal disturbances. stabilizing coastal sediments, providing food and

The highest species diversity of seagrass is found shelter for diverse organisms, as a nursery ground for

near the tip of Cape York in the very north, with a shrimp and fish of commercial importance, and for gradual decline in diversity moving south down the nutrient trapping and recycling"". In eastern Australia east coast'". This is thought to be a result of - the marine mammal, Dugong dugon, and the green sea graphic distance from a center of diversity in the turtle, Chelonia mydas. feed directly on seagrasses. Malaysian/Indonesian region driven by the east Both animals are used by traditional Australian

Australian current which runs roughly north to south""', communities for food and ceremonial use. Both species combined with changes in temperature, topography have declined in number, and protection of their habitat

(available substrate], past changes in sea level and and food source is vital. exposure to wave action'". The extent of seagrass areas and the ecosystem

The temperate species in the southern half of the values of seagrasses are the basic information required

region include members of the genera Amphiboiis, for coastal zone managers to aid planning and

Posidoniaaud Zosfera which are found predominately in development decisions that will minimize impacts on WORLD ATLAS OF SEAGRASSES

seagrass habitat. In general, our knowledge of intertidal and the 2 600-km Great Barrier Reef with its reef and shallow subtidal (down to 10 ml distributions is platforms and inshore lagoon. good; however, we have only a basic understanding of Carruthers et a/."" classified the northeast coast deepwater (>10 ml seagrasses throughout the region. It seagrass systems into river estuaries, coastal, is important to document seagrass species diversity and deepwater and reef habitats. All but some of the reef distribution and identify areas requiring conservation habitats are significantly influenced by seasonal and measures before significant areas and species are lost. episodic pulses of sediment-laden, nutrient-rich river flows, resulting from high-volume summer rainfall. BIOGEOGRAPHY Cyclones, severe storms and wind waves, as well as Gulf of Carpentaria and Torres Strait macrograzers (dugongs and turtles) influence all

The Gulf of Carpentaria is a large, shallow, muddy habitats in this region to varying degrees. The result is marine bay. Extensive open coastline seagrass a series of dynamic, spatially and temporally variable communities, mainly of the genera Halodute and seagrass meadows. Ha/op/7//aintertidally, and Syringodiumand Cymodocea River estuary habitats include a wide range of subtidally, are found along the southern and western subtidal or intertidal species and can be highly sides of the gulf'". Along the exposed eastern coast of productive. The species mixture, growth and distri- the gulf, seagrasses are generally sparse and bution of these seagrass meadows are influenced by restricted to the leeside of islands, protected reef flats, terrigenous runoff as well as temperature and salinity and estuaries and protected bays. The coastline of the fluctuations. Increased river flows in summer cause eastern gulf is extremely shallow and regularly higher sediment loads and reduced light, creating disturbed by prevailing winds. Sediments throughout potential light limitation for seagrass"". Associated the gulf are predominately fine muds, and these are erosion and unstable sediments make river and easily resuspended due to the shallow bathymetry habitats a seasonally stressful environment for resulting in increased turbidity, which restricts seagrass growth. These meadows often have high seagrass distribution and growth. Reef flat communi- shoot densities but low species diversity'". Differences ties are dominated by Thatassia. Meadows in estuaries in life history strategies, resilience to habitat variability, and sheltered bays are mostly of the genera Halodule, and the physical characteristics of the inlet act to with Cymodocea and Enhalus. control species assemblages in different river and inlet

The Torres Strait is a shallow (mostly 10-20 m systems. depth) body of water 100 km long and 250-260 km Coastal habitats also have extensive intertidal wide (east-west), formed by a drowned land ridge and subtidal seagrasses. Intertidal environments are extending from Cape York to Papua New Guinea. The impacted by sediment deposition, erosion, tidal area has a large number of islands, shoals and reefs. fluctuations, desiccation, fluctuating and sometimes Reefs are generally aligned east-west, streamlined very high temperature, and variable salinity'"'. Tidal by the high-velocity tidal currents that pour through range can be as large as 6 m. These communities are the inter-reef channels. Seagrass communities occur affected rapidly by increased runoff with heavy rain or across the open seafloor, on reef flats and subtidally cyclone events""', but a large and variable seed bank adjacent to continental islands. A well-defined line of can facilitate recovery following disturbance"^'. Inshore large reefs runs northwards from Cape York, seagrass communities are found in varying quantity including the Warrior Reefs with extensive seagrass- along the eastern Queensland coastline, mostly where

covered reef flats. Mixed species occur on these flats, they are protected from the prevalent southeast winds most commonly of the genera Halodule, Thalassia, by the Great Barrier Reef. Along the southern Thalassodendron and Cymodocea. The large ex- Queensland coast, the Great Barrier Reef offers little panses of open water bottom are covered with either protection and coastal seagrass meadows are sparsely distributed Halophila or mixed species restricted to sheltered bays, behind headlands and in {Halodule, Thalassia and Syringodium] communities. the lee of islands. Extensive coastal seagrass meadows

Lush Halophila ovalis and Halophila spinulosa occur in north-facing bays such as Moreton Bay, Hervey

communities are also found in the deep waters Bay and Shoalwater Bay

|>30 m) of the southwestern Torres Strait. Increasing distance from the coast decreases the

impacts from pulsed terrigenous runoff, and in these Northeast coast regions clear inter-reef water at depth (>15 ml allows

Tropical seagrass habitats in northeastern Australia for deepwater seagrass growth. Throughout the Great are extensive, diverse and important for primary and Barrier Reef region, approximately 40000 km^ of secondary production""'. A high diversity of seagrass lagoon and inter-reef area has at least some seagrass,

habitats is provided by extensive bays, estuaries, rivers most of low density (<5 percent cover)''". Eastern Australia 121

Deepwater seagrass areas are dominated by (46' e ;„,„.,, .v™« ISO'S < Cape Von> i species of Halophlla" ^^'''. Large monospecific mead- ^. . J

of seagrass occur In Ifiis liabitat composed mainly ows ^ y^ Fniuev: Cliarhlh- Bm of Haiophila decipiens or Halophila spinulosa. / Carpvniana Halophila spp. display morphological, physiological and ^\ CORAL St A

^i "''-'^'" Inland life history adaptations to survival In low-light environ- ^,_ V * ments. Halophila spp. can be annuals In the Great * &« ^'^^^^ Barrier Reef »C! World Heritage Area region, rapid Barrier Reef have growth rates and are Townsville^w Bowef^^ft considered to be pioneering species"". An Important 20* S characteristic of this strategy is high seed production. Nontiem Rates of 70 000 seeds/m'/year have been estimated TwTitofy Queensland Veppoon tfjC, from field observations of Halophila tricostata'^". JL llmvv The distribution of deepwater seagrasses W~ Bm appears to be mainly Influenced by water clarity and a Deception Bm' ' AUSTRALIA "'ansbanei~ M,.u„,„ combination of propagule dispersal, nutrient supply 0,1, and current stress. High-density deepwater sea- South grasses occur mostly on the inner shelf in the central Australia 30° S narrow-shelf section of the east coast which Port Macquane _ New South Wales experiences a moderate tidal range and is adjacent to high-ralnfall rainforest catchments. Where there are A ^'"'^y-BolmyBm large tidal ranges, just to the south of Mackay, no major >/J/*k Adelaide b* exist, deepwater seagrass areas but some meadows i 4/)'- °. G occur further south in Hervey where tide ranges Bay Coomng \ Melbourne, . Mallacoota Likes •, _ 4j» moderate again'". Deepwater seagrasses are uncom- PortHacldng^ • -y"-*^ »•„«,„,»„,«„, mon north of Princess Charlotte Bay, a remote area of y Bam Sirun » 40" S fori Phillip Bay' k T low human population and little disturbance. This may Tasmania - • Freyanet the result of the east Australian current diverging at be 200 400 600 Kilometers J ,.^' ^^H^^II^-^^H - Umnv Island 1 Princess Charlotte Bay and the far northern section may not receive propagules for colonization from Map 11.1 southern meadows. Much of this coast is also silica Eastern Australia sand and low in rainfall and stream runoff, and It is possible that limited availability of nutrients restricts the most common as they dominate in estuaries and seagrass growth'". coastal lagoons'^". In Victoria and Tasmania, Posidonia Reef seagrass communities support a high and Amphibolis are also found, mainly near estuary biodiversity and can be extensive and highly productive. entrances, or In sheltered bays adjacent to Bass Strait Shallow unstable sediment and fluctuating tempera- Islands. ture characterize these habitats. Low nutrient availa- The distribution and occurrence of seagrasses bility is a feature of reef habitats, and seagrasses are depends on the estuary type. I.e. drowned river valley, likely to be nitrogen limited"". Seagrasses are more barrier estuary or coastal lagoon"". Seagrass species likely to be present on reefs with vegetated cays than on composition and distribution is associated mostly with younger reefs with highly mobile sand. Intermittent sediment type and with differing exposure to wave sources of nutrients arrive when seasonal runoff energy from the open ocean. Seagrasses are generally reaches the reef. In some localized areas, particularly more abundant several kilometers upstream from the coral cays, seabirds can add high amounts of estuary entrance due to lesser tidal and wave phosphorus to reef environments. The more successful disturbance. Seagrasses In coastal lagoons may also be seagrass species in reef habitats of the Great Barrier affected by the frequency with which the lagoon

Reef Include Thalassia hemprichii, Cymodocea entrance is open to the ocean or closed by shifting sand rotundata, Thatassodendron ciliatum, the colonizing banks, changing conditions from brackish to saline. species Halophila ovalis, and species of the genus Agricultural development and poor catchment practices

Halodule. in some regions have resulted in high sediment and nutrient loads reducing light availability and favoring New South Wales, Victoria and Tasmania species which can tolerate lower light levels. In other Ten species of seagrass (excluding Lepilaena cylindro- localities, reduced freshwater flows (due to industrial

carpa] are recorded In this region'™. Species of the and agricultural extraction! have Increased salinities. genus Zostera (Including the former Heterozostera] are In protected sites, mixed stands of Zostera ^ff ^ WORLD ATLAS OF SEAGRASSES

tasmanica, Zostera capricorni (formerly Zostera enclosed waters such as tvloreton Bay and Westernport muelleri] and Halophila avails dominate. Ruppia Bay have undoubtedly influenced the modern

meadows are common In areas of high freshwater distribution of seagrasses, particularly in temperate

input. A feature of estuarine habitats in this region is waters. Less easy to determine is the likely effect In heavy winter-spring rains with associated high turbidity, tropical waters where turbidities are already naturally followed by high salinity and low rainfall in summer. high. Dramatic declines in grazer populations (turtle

In less-protected areas dominated by sandy and dugong! from increased hunting would be expected sediments le.g. north coast of Tasmania. Bass Strait to allow an Increase in seagrass, particularly of islands! mixed seagrass communities consist of larger, biomass where climax communities can now develop. slower growing species such as Posidonia australis. with Traditionally, the fruit of Enhalus acoroides was small, faster growing species such as Zostera tasmanica eaten in the northern islands and the leaf fibers were and Halophila ovalis occupying the gaps between possibly used to make nets and cord. This use was meadows and areas close to freshwater inputs. At the likely to have been infrequent and of low Importance to

mouth of some bays and in areas dominated by sandy seagrass distribution as the human population was siliceous sediments and exposed to ocean swells in very small before European migration. Seagrasses Victoria, the slow-growing seagrass Amphibolis were used to make matting and for bed mattresses antarctica [Amphibolis gnffithii fills the same role in during the Second World War. They were also used for

South Australia! forms patches of varying sizes rather fertilizer, such as in in southeastern than extensive monospecific meadows. In these areas, South Australia, where Posidonia angustifolia leaf drift

nutrient inputs are low and sediments are nutrient poor. and wrack is still harvested from the beach for soil

Large oceanic bays In southeast Tasmania have conditioner and compost mixes'"'. Such activities are

meadows of Halophila and Zostera species. Seagrass now illegal in many parts of Australia where both live distribution is influenced by biogeography and geo- and dead seagrasses are protected. morphology as well as wave energy. Deep, oceanic There are reports from the southern and eastern seagrass beds of Posidonia australis and Amphibolis Australian coastline that seagrass communities have

antarctica are also present to depths of 22 m in clear declined in recent decades'^". Anecdotal reports of 30

non-polluted water. Their distributions are influenced by years ago from residents in the Hervey Bay and Great

depth, bottom type, wave energy and geomorphology. Sandy Strait region describe large long-leaved l>30 cm!

Most seagrasses in southeastern Australia are restric- Zostera capricorni meadows abundant over the ted to depths of less than 20 m by light availability. intertidal banks. Long-time residents report abundant

fishing and bird life (especially black swans! and say

South gulf coast of Southi Australia that the seagrass wrack was so plentiful that it was

Seagrass distribution in South Australia is dependent harvested from the beaches for garden mulch. Today,

on coastal topography, bathymetry and environment''". much of the seagrass on the Intertidal banks in the

.The most extensive meadows are found in the large region is sparse or low-cover Zostera capricorni with

expanses of sheltered shallow water in Spencer Gulf short (<10 cm! and narrow leaves. Fishing is reported and Gulf St Vincent. These are predominantly Posidonia to have declined and black swans no longer frequent and Amphibolis meadows, with Halophila and Zostera the region. Unfortunately, accurate mapping programs species. Large seagrass meadows which are were not instigated until the late 1980s so these types

dominated by species of Zostera also occur along the of report are Impossible to verify and may well be

southeastern coast of South Australia in coastal overstated.

lagoons le.g. Lake Alexandnna and Lake Albert!. In Victoria there are unquantified reports of

Zostera loss in Westernport Bay during the 1950s. The

HISTORICAL PERSPECTIVES decline coincided with a reduction in fish catches.

Australia has had a relatively stable climate with the Anecdotal reports and photographs from local

northward movement of the continent compensating residents in the north and eastern regions of

during past episodes of global cooling. The biomass Westernport Bay, prior to the loss of seagrasses,

and diversity of seagrass seen today Is most likely to describe "lush seagrass meadows". Similarly in Corner

have remained relatively unchanged on a continental Inlet, Victoria, a decline in Posidonia australis in the

scale for tens of millions of years. 1960s was followed by a reduction in fishermen

Agriculture and coastal development started in operating in the region'^".

Australia with the arrival of European migrants only 200 years ago and coastal Influences on seagrass AN ESTII^ATE OF HISTORICAL LOSSES before that date would have been almost entirely More than A50 km' of seagrass have been lost from

natural. Sediment and nutrient loads to estuaries and Australian coastal waters In recent years, largely Eastern Australia 123

attributed to eutrophication, natural storm events, and thousands of hectares of seagrass. which were present reductions in available light due to coastal prior to the 1 980s, have been destroyed by the effacts of development. It is worth noting that there is a high canal estate development. Deception Bay seagrasses probability of bias tow/ards reporting decline, and that have declined since 1996 in what may be a cyclic increases in biomass and area are often not reported. pattern. Both cases were due to low light and poor There have been several well-documented cases of seagrass loss in eastern Australia over the past 50 years'"'. In Port Macquarie iNew South WalesI 1 1 .3 km' of seagrass was lost between 1953 and 1985 due to increased turbidity from human activity, resulting in declining fish stocks'"'. Similarly in Botany Bay, a loss of 2.5 km' of Posidona sinuosa, representing 58 percent of the bays seagrass, was lost between 19i2 and 1986, a consequence of dredging activities and eutrophication''*'.

In South Australia there has been a significant decline in seagrasses on the eastern side of Gulf St

Vincent due to sewage effluent. Approximately 60 km' of Posidona sinuosa and Amphibolis antarctica meadows were lost between 1935 and 1987'"'. In Spencer Gulf, fishermen and local residents have reported widespread loss of Amphibolis close to the Rob Coles visually estimating seagrass aL.. . :-d mapping intertidal zone. Recent loss (1992-931 of mixed distribution (using differential GPSI, Sfioalwater Bay, Queensland. meadows of Posidonia australis, Zostera tasmanica and Zostera capricorni were due to sediment accretion water quality associated with urban development and and desiccation caused by exposure to high air possibly agriculture"". Loss from climatic events temperatures and low humidity'"'". (storms, flooding and cyclones] has occurred in a

In Victoria, the recorded loss of seagrass has number of regions including Hervey Bay 11 000 km'' and been from the large marine bays of Westernport Bay, 27.75 km' in separate events in the 1990sl and

Port Phillip Bay and Gippsland Lakes. In Westernport Townsville. Anecdotal evidence and evidence collected Bay, persistent high turbidity and poor water quality during lobster fishery surveys suggests that thousands due to agricultural runoff, sediment inputs and of hectares have been lost in the northwest Torres resuspension of sediments caused seagrass to decline Strait due to flooding and sedimentation from Papua from 196 km' in the early 1970s to 67 km' in 198/1'"'. New Guinea, but these are remote locations and Seagrass recovery has occurred (15i km' by 2001)"*', difficult to track effectively. but seagrass meadows have failed to recolonize the In northeastern Australia, most seagrass losses intertidal mud flats in north and western regions and in have been followed by significant recovery. For some areas seagrass meadows have at least 45 percent example, approximately 1 000 km' of seagrasses in lower biomass compared to 25 years ago"". A near Hervey Bay were lost in 1 992 after two major floods and complete loss of seagrass lea 31 km'l in the Gippsland a cyclone within a three-week period added to

Lakes from the 1920s to 1950s coincided with reduced pressures on the system from agricultural commercial fish catches'"™. More recent estimates of development and land development associated with seagrass abundance suggest that there has been little increases in human populations"". The deepwater decline over the past 30 years'"" except for some seagrasses died, apparently from light deprivation localized replacement by algae. Similarly, in Port caused by a persistent plume of turbid water from the

Phillip Bay, little change in seagrass area was recorded floods and the resuspension of sediments caused by from 1957 176 km'l to 1981 196 km-'l"""'. From 1981 to the cyclonic seas. The heavy seas uprooted shallow-

2000, the area of seagrass in Bay declined water and intertidal seagrass. Recovery of subtidal from 96 km' to 68 km""', possibly due to increased seagrass lat depth >5 ml began within two years of the turbidity and eutrophication in Corio Bay and Swan Bay initial loss"", but recovery of intertidal seagrasses was

(early 1990sl in the west and southwest of Port Phillip, much slower These seagrasses only started to recover respectively. Drifting algal communities have replaced after four to five years and did not fully recover until some areas of seagrass vegetation. December 1998"".

In Queensland, declines of seagrass area resulted The capacity of tropical seagrasses to recover from flooding and sedimentation. In Moreton Bay, appears to be a consequence of morphological,

*- * tf^ 124 WORLD ATLAS OF SEAGRASSES

physiological and life history adaptations; the plants can sediment accretion'"'. Zostera capncorni meadows

be fairly resilient in unstable environments. Halodule were found to recolonize through vegetative growth and uninervis and Halophila ovalis are considered pioneer can therefore survive small-scale disturbances'""'.

species, growing rapidly and surviving well in unstable Queensland's east and gulf coasts have areas or depositional environments'""', Halophila tricostata where seagrass meadows have expanded. Little is

is an annual, only appearing in late September through known about long-term cycles in seagrass meadow

to February and being sustained by a sizeable seed size and biomass. The losses and gains being bank'"". Cymodocea serrutata occurs in deeper measured may fall within a natural range. In heavily sediments and has been linl

Case Study 11.1 MAPPING DEEPWATER (15-60 M) SEAGRASSES AND EPIBENTHOS IN THE GREAT BARRIER REEF LAGOON

Seagrasses in waters deeper than 15 m in the Great reef edge up to 120 km from the coast. Seagrass Barrier Reef World Heritage Area were surveyed presence, species and biomass were recorded with between 199'1 and 1999. A real-time video camera depth, sediment, Sechii disk depth, associations

and dredge were towed for four to six minutes on with algae and epibenthos, and proximity to reefs.

1 ^26 sites to record bottom-habitat characteristics Five seagrasses were present, all from the

and seagrasses. In conjunction with the camera tow, genus Halophila, in depths down to 60 m. Sea-

a sled-net sample of benthos and a grab sample of grasses were present at 33 percent of sites the sediment were collected. sampled- The species Halophila ovalis, Halophila Sampling included the Great Barrier Reef spinulosa. Halophila decipiens. Halophila tricostata

province from the tip of Cape York Peninsula at 10°S and Halophila capncorni were found. Halophila

to approximately 25°S, or 1 000 nautical miles of tricostata is a species endemic to northern

coastline. Sites were located from inshore out to the Australia and Halophila capncorni is found only in the southern Indo-Pacific. All other species are broadly distributed throughout the Indo-Pacific

region"". Most seagrass seen in video tows was of low density |<5 percent cover] and biomass ranged

from less than 1 g to 45 g dry weight/m' (the highest was recorded from a Halophila sp/nu/osa-dominant

meadow in 21 m). Mean biomass was 3.26 ±0.36 g dry weight/m^

The map of seagrass was generated using generalized additive models incorporating Loess smoothers'"'. The degree of smoothness was

minimized but sufficient to account for both spatial effects and spatial correlation The location of the data points was receded based on the proportion of the distance the point was located between the coast and the outer edge and the proportion from 10°5 to the southern edge. The model estimated that as much as 40000 km^ of lagoon and inter-reef area may have at least some seagrass'"". This type of map

or statement of probability is necessary when

factors such as depth make it impossible to plot

around the edge of the meadow even if that could be

defined. With areas of very low biomass and very large areas with patchy seagrass, the concept of a

defined meadow is not always appropriate. Using

Probability of occurrence of deepwater seagrasses in the Great probability to estimate the likelihood of seagrass

Barrier Reef Lagoon Icontours obtained by spatial smoothing!. presence must be explained with care as the Eastern Australia 125

turtle populations, increases in meadow size and Queensland Department of Primary Industries IQDPII biomass may reflect simply changes (decreases! in mapped 18A km" in the eastern gulf'"' and 225 km' herbivore populations and be an indicator of around the Wellesley Island Group (southern gulf) in disturbance rather than a positive measure. 1984"^ Using probability models and ground-truthing.

AN ESTIMATE OF PRESENT COVERAGE the Torres Strait is estimated to contain 13425 km- of

Gulf of Carpentaria and Torres Strait seagrass habitat on reef platforms and non-reef soft

Approximately 779 km' of seagrass in the western Gulf bottoms''^ '". much of which is valuable habitat for of Carpentaria were mapped in 198^'°'. In 1986, juvenile commercial shrimp.

outcome may be scale dependent and the outcome

is definitely not a "map" in the sense it is normally 40

used. If you define the sampling unit as the entire ^U Halophila decipiens ^^ Great Barrier Reef Region, the probability of finding Halopiiils spinulosa Halophila ovalis seagrass in that sampling unit will be 100 percent, A ^ — Bi Halophila tricostata — smaller unit will have a lower probability Typically S ,,. Halophila capricorni the ability of a map drawn this way can be improved ^ m Seagrass present if physical factors such as light and bottom-type B 20 location can be incorporated in the model, "o &15 1 DEEPWATER SEAGRASSES

Deepwater seagrasses were most common in the 1 10 — 11- — Li central narrow shelf regions which experience a 5 1 moderate tidal range and are adjacent to high- IT' a rainfalt rainforest catchments. Highest densities 1 1 1 occurred between Princess Charlotte Bay and 15-25 25-35 35-i5 45-55 55-65 Cairns, and south of 23°S. Halophila tncostatawas Deptti strata (ml found only between Princess Charlotte Bay and

Mackay, Other species were spread throughout. Frequency of probability of occurrence (percent adjusted for

Seagrasses [Halophila ovalis. Halophila spinulosa. sampling frequency] of seagrasses within each depth stratum. Halophila decipiens and Halophila capncorni]

occurred to 60 m depth. The frequency of occurrence Note: Seagrass present = all species combined (including

of seagrasses declined below 35 m, Halophila unidentified].

decipiens was the most commonly found species at

all depths. Dense algae beds (mainly Caulerpa and principles of comprehensiveness, adequacy, and

Halimeda] were found on the outer shelf north of representativeness. This "representative areas"

Cooktown. Where there are large tidal velocities and program has used two processes: a data-based ranges {i-6 m tidal range], just to the south of statistical approach and a delphic expert Mackay. no major deepwater seagrass areas occur experience-based questionnaire approach. Thirty- Some seagrass habitats were apparent further eight relatively homogeneous inter-reef bioregions

south in Hervey Bay where tidal ranges moderate. have been identified based on the presence and The ecological role of inter-reef seagrasses distribution of seagrasses. algae, other benthos,

and algae is not well understood. Some deepwater sediment and habitat descriptions. This information

meadows l<25 m) of Halophila ovalis and Halophila will be used to select areas to protect in "no-take"

spinulosa are important dugong feeding habitat. zones and to minimize the loss of economic use of Commercial fish and crustacean species were reef areas by the tourist and fishing industries and

uncommon in deep water compared to catches in by recreational users. The deepwater seagrass and

coastal intertidal and shallow subtidal meadows'"'. epibenthos mapping is an excellent example of This seagrass and benthic community seagrass maps being used directly to support good

information is one of the major databases management decisions.

supporting development of a multi-use marine park

plan tor maintaining the biodiversity of the Great

Barrier Reef World Heritage Area based on the Source: Coles et al 126 WORLD ATLAS OF SEAGRASSES

Northeast coast It IS difficult to estimate the exact seagrass area The northeastern Australia coastline is either within as published information is from overlapping zones and the Great Barrier Reef World Heritage Area with high information is being constantly updated as mapping conservation values or includes coastline with sea- improves. The most accurate estimates of seagrass grass meadows supporting valuable shrimp fisheries, meadows along the northeast coast are 5668 km' green turtle or dugong populations. The perceived intertidal and shallow subtidal (down to 15 m water

importance of seagrasses in these regions, as well as depth!''"'"'. concern about the downstream effects of agriculture, From Cape York to Cairns, seagrass communities effects of fishing and the possibility of shipping are predominantly subtidal Halophita species with

accidents""', have led to an extensive mapping program. approximately equal area of sparse and dense cover Broad-scale surveys conducted between 198^ and 1989 Species of Cymodocea and Synngodium are found in mapped seagrass habitats down to 15 m depth in shallow subtidal areas where there is shelter from the estuaries, shallow coastal bays and inlets, on some southeast winds. Between Cairns and Bowen, around

fringing reefs, barrier reef platforms, inner reef and 70 percent of the area of seagrass is less than 10 Great Barrier Reef Lagoon""'. Since 1989 there have percent cover and mostly a mixture of Halodute and been repeated surveys at finer scales of resolution in Halophila species, both intertidal and subtidal. certain localities as a result of specific issues le.g. port Between Bowen and Yeppoon approximately 50 percent developments, dugong protection areas). Some studies of the area of the mainly intertidal Halodule have repeated surveys at a locality once or twice yearly communities is between 10 and 50 percent cover South

for up to four or more years'""'. of Yeppoon, the seagrass communities are mostly

Case Study 11.2 Point (eastern region) and Point Leo (southwest WESTERNPORT BAY region). From 1956 to 1974, there was a decrease in seagrass distribution at three (Rhyll, Corinella and

Westernport Bay is a large estuarine tidal bay in Stony Point) of the four sites. From 1973-7i to 1983- of and southern Victoria. It encloses two large islands and 84 an 85 percent reduction seagrass

has an area of 680 km' of which 270 km' is intertidal macroalgal biomass, from 251 km' to 72 km', was "', mud flat. Intersecting the mud flats is a series of reported in the bay'"' much of it on intertidal complex channels where sediment movement is banks. A number of studies examined the causes of

influenced by the water movement patterns in a net this dramatic loss of seagrass habitat'"'"'"' focusing clockwise direction. on the effects of light reduction on seagrass

Westernport Bay is an area of high biological communities as a result of increased sediment

diversity because of its wide range of habitats, loads in the water column. These studies also including seagrass meadows, mangroves, salt examined the increased elevation of intertidal banks,

marsh and deepwater channels. It is an inter- the loss of pooling and the increased exposure of nationally significant coastal wetland acknowledged seagrasses to desiccation, a consequence of

by nomination to the Ramsar Convention on increased sediment inputs from catchment sources Wetlands. The bay consists of extensive intertidal and resuspension of sediments in the water column. seagrass meadows, subtidal meadows and macro- Annual sediment inputs from the northeastern algal communities. The dominant seagrasses are catchment (>86200 mVyear) were found to be six to Zostera tasmanica and Zostera capncorni. The seven times the loads of sediments into other

dominant macroalga associated with seagrass is regions of the bay (13000 mVyear)"" leading to Caulerpa cactoides. which, with other algae, decline in light availability in this region. Other comprises about 16 percent of the total marine causes such as the effects of industrial effluents on vegetation. invertebrate fauna and subsequent reduced grazing

The catchment to the north of Westernport Bay of epiphyte loads were examined. No conclusive

was cleared of vegetation in the late 1800s for evidence was found that identified a single major

agriculture, and the bay is now subject to inputs of factor as the cause of seagrass loss. The effects of

nutrients and suspended particulates"". Change in seagrass loss on fish populations were also studied seagrass distribution from 1956 to 2000 was and findings suggested that Westernport Bay

examined using aerial photography at four sites m seagrass meadows play an important role in

Westernport Bay"^'. The four sites were Rhyll enhancing fish production and marine invertebrate

(southern region), Corinella (eastern region], Stony numbers'"'. 1

Eastern Australia 127

denser, with approximately 60 percent of the area of Hawkesbury region and Port Hacking, but this seagrass greater than 50 percent cover These information is not yet available. seagrass areas are dominated intertidally by The Victorian Department of Natural Resources Zostera/Halodule communities and subtidally by and Environment has recently produced maps for bays Halophila communities. and inlets of Victoria that include 470 km' of seagrass.

Waters of the Great Barrier Reef World Heritage Fine-scale maps 11:100001 detailing seagrass species

Area deeper than 15 m have been surveyed and it is composition and estimates of abundance have been

likely that as much as 40000 km' of habitat that may produced for large bays including Gippsland Lakes, support seagrass populations is present in the reef Corner and Nooramunga Inlets, Westernport Bay and

lagoon''". The map in this case was based on spatial Port Phillip Bay Smaller inlets that have been mapped probability and cannot be compared with a map drawn include Anderson, Mallacoota, Shallow, Sydenham, from global position system points taken on the edge of Tamboon and Wingham Inlets. The dominant seagrass a meadow. communities include sparse to dense meadows of Zostera tasmanica, Zostera capncorni and Posidonia New South Wales, Victoria and Tasmania australi^''".

Estimates of seagrass area in New South Wales from The Tasmanian Aquaculture and Fisheries

mapping exercises prior to 1985 were 155 km* in 1 1 Institute mapped areas of seagrass in six bioregions of estuaries. In New South Wales the Conservation Tasmania. The total area of mapped seagrass was 845

Division of New South Wales Fisheries is presently km^ The Boags, Flinders and Freycinet bioregions have

mapping seagrasses in large estuaries of the been mapped primarily from aerial photographs and

Subsequent mapping of seagrass and These regions are closest to inputs of nutrients and

macroalgal habitats in Westernport Bay in 1995 sediments from a rapidly expanding urbanized

showed that seagrass and macroalgal cover in the catchment with extensive agricultural activities.

bay had partly recovered, from an area of 72 km' in Management strategies are being implemented to

1983-84 to 113 km-' in 1995. A further increase to 154 improve water quality in the northeast region by

km' was recorded in 1999'™', Despite these reducing flows of freshwater and loads of nutrients

increases, the seagrasses in the north and and sediments. These strategies are useful, but

northeast regions of Westernport Bay either remain existing sediment resuspension issues and changes

in poor condition or have not recovered"'"'. This is to intertidal bank topography will limit the possibility

likely to be a result of poor water quality as of full recovery of seagrass in this region. chlorophylls and suspended sediment concen-

trations increased in the northeastern waters of Westernport Bay between 1975 and 2000"". This

trend has reduced light availability and reduced the

biomass and productivity of seagrasses.

In April 2000, the effects of poor catchment

practices and water quality again resulted in

hundreds of hectares of seagrasses being lost during

a flood event. Although some recovery of seagrasses

has occurred over the last 15 years, seagrass

meadows in Westernport Bay would still appear to be threatened by flooding and high turbidity even over

time periods as short as days to weeks.

The range of information from published papers and technical reports on Westernport Bay

fails conclusively to attribute a single cause to the

dramatic loss of seagrass from 1974 to 1984. By

1999, seagrasses in the region had shown some

recovery, more than doubling the area present in

1984. Nevertheless, there are vast regions in West-

ernport Bay that have failed to recover, or they are at

their threshold of survival during high turbidity"". Distribution of estuarine habitats in Westernport Bay, Australia. 128 WORLD ATLAS OF SEAGRASSES

LANDSAT (1:100000 or greater!. The Bruny bioregion of the coast have a species gradient from entrance to

has been recently mapped in detail from aerial head with Posidonia species being replaced with photography with extensive ground-truthing'^- "'. No Amphibolis along the gradient. Three genera. Zostera,

mapping has been conducted in the Davey, Franl

Otway bioregions, but it is unlikely there is much mud flats occur. Coastal lagoons with a marine

seagrass in these because of exposure to ocean swells environment, such as the Coorong which is 100 km long

and because of high tannin loadings in estuaries (i.e. and less than 2 m deep, are unique in this region. They Port Davey and Macquarie Harbour!'^". feature an association of marine and brackish water genera such as Ruppia. Zostera and Lepilaena together

South gulf coast of Soutfi Australia with some marine algae'""'.

Seagrasses in South Australia cover an area of approximately 9 620 km'. Shepherd and Robertson'"' USES

recognize three seagrass zones: exposed coasts, gulfs Seagrass habitats in this region are noted for their and bays, and coastal lagoons, each with different importance as nursery areas for juvenile fish and for species composition. The exposed coasts are mainly the commercial penaeid shrimp fishery in

patchy Posidonia typically where islands or reefs give northeastern Australia. Coles et a(.'"' recorded 134

local protection. The two gulfs which are a main feature taxa of fish and 20 shrimp species in the seagrasses

Case Study 11.3 EXPANSION OF GREEN ISLAND SEAGRASS MEADOWS

Seagrasses are an integral and important part of From the interpretation of aerial photographs, coral reef systems. The Green Island seagrass a high-density seagrass meadow of 0.39 ±0.3 ha was

meadows are one of many seagrass meadows found first visible in 1936 as an isolated patch near the

on reef platforms in the Great Barrier Reef waters"". northwest tip of the cay It appears to have expanded

At a time when declines in seagrass biomass and into the back-reef area northwest of Green Island in distribution have been widely reported. Green Island the 1950s to a small patch covering approximately

is one of the few localities in the eastern Australian 1.1 ±0.3 ha in 1959, It increased from the 1950s to 6.5

region where expansion of seagrasses has been ±1.3 ha in 1972, 15.31 ±2.29 ha in 1992, 22,71 ±3.3 ha

recorded. in 1993 and 22.9 ±2.4 ha in 1994. A survey in 1997

Green Island is a vegetated coral cay located found little change'^^'.

approximately 27 km northeast of Cairns. Ground- In 1994 Halodute uninervis (average above-

truthmg and mapping of seagrass distribution was ground biomass, all sites pooled, 16.61 ±1.4 g dry

conducted in 1992, 1993 and 1994. Systematic weight/m'l was the dominant species in the meadow. mapping by transects was adopted on each occasion Cymodocea rotundata was the next most common

and vertical aerial photography 11:120001 was used if species 13.95 ±1 .6 g dry weight/m'l, with Cymodocea captured within the same season that ground serrulata and Synngodium isoetifolium occurring in

surveys were conducted. Transects were located small patches of the meadow (4.12 ±0.7 g dry

along compass bearings from permanent markers. weight/m'l. Halophiia ovalis (0.91 ±0.3 g dry weight/ A theodolite was used to accurately determine m^l occurred intermixed with Halodule uninervis geographic location of survey sites (±1.5 ml. beyond the intertidal and subtidal edges of the mam

Estimates of above-ground seagrass biomass (three meadow. Thalassia hemprichiiwas uncommon in the replicates of a 0.25 m^ quadrat], species composition meadow 10.03 ±0.02 g dry weight/m'l.

and sediment depth were collected every 20 m. It has long been believed that the expansion of

Underwater video and still photography were used to Green Island seagrass meadows was the result of

provide permanent records. All data were entered biological and anthropogenic disturbances on the

onto a geographic information system. Boundaries reef. It was first thought that the increases in area of of seagrass meadows were determined based on the dense seagrass meadows to the northwest of

the geographic position of a ground-truthed site and Green Island Cay were linked to increases in tourist aerial photograph interpretation. Digitally scanned visitation and increased nutrients from the adjacent

and rectified vertical aerial photographs were used sewage outfall. This is because low nutrient to map the past 11936, 1959 and 1972) seagrass availability dominates reef habitats such as Green

distribution to the northwest of Green Island Cay. Island and seagrasses are nitrogen limited"". Eastern Australia 129

of Cairns Harbour. Seagrasses also provide food for THREATS dugong and whicfi are the subject of Ivlost Australian recorded losses of seagrass are conservation measures. probably the result of light reduction due to sediment

Apart from licensed worm and bait collecting loads in the vi/ater'"'. Quantifying loss of seagrass has there is little or no gleaning activity on seagrasses in been difficult in many locations as maps are often eastern Australia. imprecise or unreliable and local change may be

Larkum ef al."" sum up the values of seagrass in indistinguishable from map error'"'. Long-term data six basic axioms: sets are not common so the extent to which loss of

stability of structure; seagrass can be attributed to natural long-term

provision of food and shelter for many organisms; cycles is impossible to estimate. Improved mapping of high productivity; seagrass meadows will enable losses to be more recycling of nutrients; accurately measured and tracked. stabilizing effect on shorelines; Coastal development, dredging and marina

provision of a nursery ground tor fish. developments are generic threats to seagrass in the

tourist regions of Australia's east coast. While these

In our \/\evj this remains an excellent summary of issues raise considerable public interest and concern the uses and values of seagrass. they are usually closely managed through legislative

In 1972, a sewage system for hotel buildings discharge in addition to regional changes in nutrient

and public toilets on Green Island was established'™'. availability.

Sewerage effluent from this was discharged onto Seagrass composition at Green Island con-

the Green Island reef for 20 years, until December tinues to change, with a rapid increase in the area of

1992 when a tertiary treatment facility was Synngodium isoetifolium which was first recorded at

completed. It is estimated that approximately 70-100 the island in the mid-1980s. With detailed maps and m^ of sewage was discharged per day'"". With no geographic information system (GISj formats,

treatment to the effluent, it was essentially raw changes in the future can be readily quantified and

sewage (nutrient loads unknown] being dumped the dynamics of reef island seagrass meadows onto the western edge of the reef platform. better understood.

It was, however, unlikely that sewage provided

the major nitrogen source, as in September 1994, Source; Udy et a(."" and Queensland Department of Primary

Udy et al"'" measured leaf tissue '^N and recorded Industnes"*'.

values from 1 .3 to 1.7 parts per thousand suggesting that the primary nitrogen source comes from either

fertilizers or N2 fixation"^'. If the primary nitrogen source was from sewage, the seagrass would have

had a leaf tissue '^N value closer to 10 parts per

thousand"^'. It could be assumed that '^N values

would have been higher prior to the cessation of raw

sewage discharge in 1992. but '^N values tend to be

highly conservative duo to internal recycling of

nitrogen in the seagrass. Also, the expansion of the seagrass meadow before the sewage pipe was installed indicates that

increased nutrient availability associated with the

sewage outfall in 1972 was not a primary cause of the meadow expansion. This suggests other factors including water seepage and nutrient translocation from the cay, as well as regional changes

(agriculture and urban development! in nutrient

availability in Great Barrier Reef water may have |S]1936 H1959 ^1972 caused the observed expansion prior to 1972. The r, jcayvegytation reet.flal continued expansion of the seagrass meadow after

1972 may have been influenced by the sewage Seagrass distribution at Green Island in 1994, 1972, 1959, 1936.

-P T ,^ X?i 130 WORLD ATLAS OF SEAGRASSES

Although deepwater seagrasses are the least understood seagrass community, they could be impacted by coastal runoff land associated light

reduction! and to some extent prawn/shrimp trawling

activities" "', although the scale of any impact is largely

unknown and difficult to determine.

SEAGRASS PROTECTION Seagrasses are habitat for juvenile fish and

crustaceans that in many parts of the world form the

basis of economically valuable subsistence and/or

commercial fisheries. The need to manage fisheries In

Thalassia hemprichii meadow on flat adjacent to Rhizophors forest, a sustainable way has itself become a motivating factor

Piper Reef. Queensland- for the protection of seagrasses"".

Approaches to coastal management decision-

processes and tfie actual areas of seagrass destroyed making are complex, and much of the information

are generally small. exists only in policy and legal documents that are not

Coastal agriculture may add to sediment loads in readily available. Local or regional government author-

catchments and the presence of herbicides in seagrass ities have control over small jurisdictions with

sediments'" '"' is a worrying trend, as unlike small-scale regulations and policies that may apply.

coastal developments, this has the potential to destroy Approaches In eastern Australia to protecting large areas. Often the risk factors for the seagrass seagrass tend to be location specific or at least state

environment are many kilometers away In upper water- specific. The approach used depends to a large extent

sheds. The Coorong Lakes seagrasses are affected by on the tools available in law and to the cultural approach

changes in nutrients and freshwater flows in the Ivjurray of the community; In Australia these tools and

River catchment which extends from South Australia up approaches have their origin In British common law.

to central Queensland thousands of kilometers north. While there Is no International legislation, there Is Port development and the management of risk a global acceptance through International conventions

can Influence seagrass survival and many sheltered (e.g. the Ramsar Convention on Wetlands, the seagrass sites are also Important port locations. The Convention on Conservation of Migratory Species of

configuration of shipping lanes in northeastern Wild Animals and the Convention on Biological

Australia directs large ships transiting south of Papua Diversity! of the need for a set of standardized data on New Guinea into Great Barrier Reef Lagoon waters. the location and values of seagrasses. Numerous Shipping accidents remain a major concern for coastal studies worldwide have presented ideas for seagrass

habitats and, while infrequent, can be potentially protection. Cappo e( a/."'"' summarized the main

devastating. Major programs exist in the western Pacific pressures on fish habitats and seagrasses in Australia.

to provide advice on shipping-related incidents"". Leadbltter ef a/."", Lee Long et at""' and Coles and Estuarlne seagrass communities are increasingly Fortes"" expanded the implications for research and

the most threatened of the seagrass habitats in eastern management, a discussion that has Australian as well Australia" "'. As provincial centers develop along the as global relevance.

Queensland coast, rivers and Inlets are often highly

affected and need careful management to maintain Protection by legislation

these seagrass habitats and the fisheries they support'"'. In the eastern Australian states of New South Wales Coastal habitats are threatened by coastal and Queensland, marine plants cannot be damaged

development as well as the Impacts of runoff from without a permit"' "'. In Queensland, the legislation poorly managed catchments, particularly when directly protects marine plants. Marine plants are

associated with large bays such as Botany Bay, defined as "a plant (a tidal plant] that usually grows on,

Moreton Bay and Hervey Bay. or adjacent to, tidal land, whether living, dead,

Reef seagrass habitats are the least threatened standing, or fallen", a definition which includes living seagrass community with minor damage from boating plants as well as seagrass plant material washed upon and shipping activities. High tourist visitation rates and the beach. This definition recognizes the role of even

associated sewage and poor anchoring practices are dead plant material in the bacterial cycle that identified as a threat at some localities. Acute Impacts ultimately supports fisheries productivity.

such as ship groundings and associated spills would The Queensland Fisheries Act"" allows for

impact heavily on reef platform seagrasses. destruction or damage of seagrass only when a permit Eastern Australia 131

has been assessed and issued. All permit issue is common are MPAs specific to a site and designed to directed by a policy that must be taken into account by protect an area identified as having important the person delegated under the Act to make the ecosystem functions. decision. The policy requires that no reasonable The Queensland Fisheries Act"" allows for the alternative exists. In states such as Queensland, fines establishment of fish habitat areas IFHAsI that include well in excess of US$0.5 million are applicable for areas of coastal seagrass. FHAs are usually small |up to damaging seagrasses. with the possibility of associated several thousand hectares! MPAs designated specifically restoration orders. to protect fisheries habitat structure over areas

All eastern Australian states have similar considered especially important or critical to fisheries"". protections in either Fisheries Acts or in National Park In recent years there has been a growing or Ivlarine Park Acts. Australia, in fact, has approxi- realization that we should identify and protect mately 'iO legislative instruments that directly influence representative examples of the diversity of habitats and marine plant and/or seagrass management"", not processes upon which species depend rather than just including regulations and management plans that as areas identified as having some especially important subsidiary legislation may also be operationally vital to characteristic'™'. A representative area is an area that is seagrass protection. An example of this would be typical of the surrounding habitats or ecosystem at a fisheries legislation that limits areas where bottom chosen scale. This approach would: trawling can take place. maintain biological diversity at the ecosystem. habitat, species, population and genetic levels; Protection by nnarine protected areas iMPAs) allow species to evolve and function undisturbed; Overlying state and local approaches, Australia also provide an ecological safety margin against has national legislation addressing international issues human-induced and natural disasters; such as treaties and conventions including the provide a solid ecological base from which

Convention on International Trade in Endangered threatened species or habitats can recover or

Species of Wild Fauna and Flora ICITESI and world repair themselves; heritage area declarations. The Great Barrier Reef maintain ecological processes or systems.

World Heritage Area is protected in legislation by the world's largest MPA, the Great Barrier Reef Marine Typical of establishing a representative area

Park. This is unique in that it possibly has as much as approach to protecting seagrasses is the need for very

40000 km' of seagrass'^', much of which is afforded a detailed maps and quantitative data on species and level of protection by the MPA. This can lead to biomass. Presently this information is inadequate for confusingly high levels of regulation; a seagrass many of our seagrass areas. Compiling a global report scientist working in east coast tropical Queensland card and synthesis of seagrass knowledge will provide a requires permits and must meet conditions from base for future protective decisions and implementation. national and state authorities. However, the Great Barrier Reef Marine Park AUTHORS model would not be appropriate in many situations as Rob Coles, Len McKenzie and Stuart Campbell, Queensland Department the money to fund a large administrative authority, of Primary Industries, Northern Fisheries Centre, PO. Box 5396, legislative support, ongoing research and long-term Cairns, Queensland 4870, Australia. Tel: +61 1017 4035 0111. monitoring, and compliance is not available. More Fax: +61 1017 4035 4664, E-mail: rob.colesriadpi.gld.gov.au

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of seagrass. In: Butler A, Jernakoff P (edsl Seagrass in Australia: Committee on the Project 88/91 : Consequences for Commercial

Strategic Review and Development ofanR&D Plan CSIRO, Fisheries of Loss of Seagrass Beds in Southern Australia. Victorian

Collmgwood. pp 116-139. Institute of Marine Sciences, Victoria.

59 Haynes D. Michalek-Wagner K [2000al. Water quality in the Great 78 Sargeant 1 (19771. A Review of the Extent and Environmental Effects

Barrier Reef World Heritage Area: Past perspectives, current of Erosion in the Westernport Catchment. Environmental Studies

issues and new research directions. Marine Pollution Bulletin itV. Series Publication No. 174. Ministry for Conservation. Victoria.

428-434. 79 Lee Long WJ, Coles RG. Helmke SA. Bennett RE [1989]. Seagrass

60 Haynes D. Ralph P, Prange J, Dennison B [2000bl. The impact of Habitats in Coastal. Mid Shelf and Reef Waters from Lookout Point

the herbicide Diuron on photosynthesis in three species of tropical to Barrow Point in North-eastern Queensland. QDPI Report to the

seagrasses. MannePoKudoneuHetin 41: 288-293. Great Barrier Reef Marine Park Authority. Queensland Department

61 Rasheed MA. Coles RG, Thomas R [2001]. Fisheries habitat of Primary Industries, Cairns.

monitoring in Queensland tropical ports - a tool for port 80 Baxter IN [19901. Green Island Information Review. Report to the - management. In: Proceedings of the 15th Australasian Great Barrier Reef Marine Park Authority August 31 . Great Coastal and Ocean Engineering Conference and the 8th Barrier Reef Marine Park Authority, Townsville.

Australasian Port and Harbour Conference, 15th- 18th September 81 Morissette N [19921. Identifying Areas of Seagrasses within the

2001. pp 89-95. Great Barrier Reef Region Threatened by Anthropogenic Activibes. 62 Lee Long WJ, McKenzie LJ. Rasheed MA. Coles RG [1996b]. Great Barrier Reef Marine Park Authority. Townsville.

Monitoring seagrasses in tropical ports and harbours. In: Kuo J, 82 Udy JW. Dennison WC (19971. Growth and physiological responses

Phillips RC. Walker Dl, Kirkman H (edsl Seagrass Biology: of three seagrass species to elevated nutrients in Moreton Bay. Proceedings of an International Workshop, Rottnest Island, Australia. Journal of Experimental Marine Biology and Ecology 217:

Western Australia 25-29 January, 1996. Faculty of Sciences, 253-277.

University of Western Australia, Perth, pp 345-350. 83 AM. Loneragan NR. Dennison WC [1996]. Light intensity and 63 Coles RG, Lee Long WJ, Squire BA, Squire LC. Bibby JM the interaction between physiology, morphology and stable isotope

[1987]. Distribution of seagrasses and associated juvenile ratios m five species of seagrass. Journal of Experimental Marine

commercial penaeid prawns in north-eastern Queensland Biology and Ecology m:<}]-1]0. waters. Australia Journal of Marine and Freshwater Research 38: 103-119. 134 WORLD ATLAS OF SEAGRASSE5

12 The seagrasses of NEW ZEALAND

G.J. Inglis

'". Zealand lAotearoal is an isolated archi- assemblages'^ Stands vary in extent, biomass and '". Newpelago, consisting of two main islands and a stability, depending upon their location'^ ' In large,

number of smaller islands whicfi lie in the shallow estuaries subject to , and on southern Pacific Ocean. Until quite recently, the platform reefs exposed to oceanic waves, stands of

seagrass flora of New Zealand was thought to consist Zostera capricorni typically consist of a mosaic of

of two species of Zostera: Zostera capricorni, which patches that range in size from less than 1 m" to 15 m''

also occurs in eastern Australia, and an endemic and which exhibit large interannual fluctuations in " "'. species, Zostera novazelandica. ITwo species of Ruppia extent'*' The largest persistent stands appear to - Ruppia polycarpa and Ruppia megacarpa - also occur occur in estuaries and embayments with relatively

in brackish and freshwater wetlands in New Zealand'", clear, tidal waters that are situated away from major but are not considered further here.l Zostera urban centers, such as Parengarenga Harbour, novazelandica was originally described by Setchell in Farewell Spit, Whanganui Inlet and estuaries of the 1933 on the basis of morphological variation in eastern Coromandel Peninsula. vegetative characters, using a relatively limited sample Despite the wide geographic distribution of

of plants'". In tact, there is quite large morphological Zostera capricorni in New Zealand, there have been

variation within natural stands of Zostera in New relatively few published studies of its extent, Zealand and reproductive structures occur infrequently demography or ecology Part of the reason for this may

in many populations'^"'. This variation has caused be its relative scarcity in many New Zealand estuaries.

considerable uncertainty in identification over the past Zostera capricorni is absent from, or occurs in century, and workers have variously referred to the relatively small areas within, many of the shallow, New Zealand Zostera as Zostera nana, Zostera turbid estuaries in New Zealand. Seagrass habitats muelleri, Zostera marina and Zostera tasmanica"'-^ ". A have been mapped in only 22 of New Zealand's 300- recent molecular phytogeny of the Zostera group, plus estuaries (Table 12.11. The areas that have been however, demonstrated that Zostera capricorni and mapped typically represent less than 3 percent of the

Zostera novazelandica are, in fact, conspecific and that total intertidal area of each estuary. Exceptions include

there is likely to be only a single species in New tidally dominated embayments, such as Whanganui

Zealand, hereafter referred to as Zostera capricorni''". Inlet and Whangamata, where seagrass meadows cover up to 31 percent and 18 percent of the intertidal DISTRIBUTION area, respectively. Just over half (5^ percent] of New Zostera capricorni occurs throughout the mainland Zealand's estuaries are unsuitable for seagrass growth

coast of New Zealand, from Parengarenga Harbour in as they are shallow, barrier-formed estuaries, built

the north to Stewart Island in the south (Tables 12.1 and around the mouths of rivers"", so Zostera capricorni is

12.2). It is found predominantly between mid and low likely to be a relatively uncommon benthic habitat in

tidal levels in estuaries and sheltered harbors'"". On the many estuarine environments. eastern coastline of the two main islands, patchy

stands of Zostera capricorni also occur on the tops of ECOSYSTEM DESCRIPTION

siltstone platform reefs in open coastal areas, where Zostera capricorni stands in New Zealand, like those

they are interspersed with algal beds and biotic elsewhere in the world, support a diverse and abundant assemblages more characteristic of rocky, intertidal assemblage of invertebrates that is often richer than s E

New Zealand 135

Piliviifitjii'ufid thirhi'lir unvegetated habitats nearby" The composition llouhora Ifafhutir of the invertebrate assemblages varies with the size V .tfhdttfiiini llmhitlir and stability of the seagrass stand and its position Koipulti lliirhnir relative to other habitats"", Builomorph and proso- Auckland (_ nfoniiUHlcl PcmnMil; ^Ujiuikati lliirlxmi -^ f Whangamata branch gastropods are distinctive components of the r AS,HAS SEA I I'liiii iiik:ii llurNni Kinvliia Harhom epibenthic fauna''". Small crustaceans and polychaetes, ID'S which are particularly abundant within seagrass Wuimcti hilcl larcwcll Spir \ are important sources of food for wading meadows, Wlum^umii hilt I v.; oystercatcher. bar- Te Angiangi birds, such as the pied Marine Ressrve

tailed godwit. pied stilt and royal spoonbill: and for IiiIl'I \ Puniiliiliiiniii Okonli) Lii^oiMi fishes such as mullet, stargazers and juvenile ' Kailiiun. IVTiin.Mil.1 flatfish""'. Seagrass fragments are also a common boutn Island 15- ^ ^^^ ZEALAND • riittiii liiiy food of garfish (family Hemirhamphidael, which are Ihrhmr Wailuiia ^ popular with recreational fishermen'"'. Lagoon 100 200 300 Kdometets Large densities of small cockles, Austrovenus *• Olii^o lUirhiiir ' Sicw-jn Mnnd • hyuniti lltii stutchburyi, and other bivalves are common in 165' E 170'^E 180' "'^". seagrass habitats" l^^lany of these species are not Map 12.1 restricted exclusively to seagrasses, but are often New Zealand more abundant within them as juveniles. Several authors have also drawn a strong historical determine how their distribution and extent have association between the distribution of seagrasses changed over time. Seagrass meadows undoubtedly and beds of the New Zealand , Pecten supported elements of the economies of pre-European novazelandiae" '''. However, the life cycle of the Pecten and early European life in New Zealand. The name novazelandiae is not dependent on seagrass habitats given to Zostera capricorni by New Zealand's and commercial stocks exist in areas where Zostera capricorni is not present'™'. A recent survey of more than 25 harbors in Table 12.1

in estuaries where benttiic northern New Zealand suggests that seagrasses may Area of seagrass New Zealand | be important nursery habitats for newly settled habitats have been mapped snapper [Pagrus auratus, family Sparidael'"'. Snapper

area of is arguably New Zealand's most sought-after marine Estuary Total fish and is the subject of a large commercial and Zostera capricorni Ikm'l recreational fishery. Adult snapper spawn in large bays, Mahurangi Harbour"*' 0.03 but juveniles are found predominantly in sheltered bays Whangateau Harbour"" 0.33 ,71 g and shallow estuaries during their first summer, before Pahurehure Inlet (Manukau Harbour they move to deeper coastal waters'™'. Snapper under Arm of "" one year old have been found in few other coastal New River Estuary"" 0.94 habitats and appear to occur mostly in clear-water, Matal

Macrophthalamus hirtipes is more widespread and not Havelock"" 0.009

necessarily restricted to seagrasses. Whanganui Inlet'™' 8.59 Avon-Heathcote Estuary"" 0.137

HISTORICAL CHANGES IN DISTRIBUTION Kaikorai Estuary"" The lack of detailed mapping and long-term study of Harwood, Otago Harbour'"' 0.82

seagrass habitats in New Zealand makes it difficult to 1

xl/ 136 WORLD ATLAS OF SEAGRASSES

indigenous Maori - rimurehia - suggests tinat they may described Zostera as "extremely common in shallow

have recognized the food value of its starchy estuaries" where it "covers the muddy floor... for many

underground rhizome. Rimu is the general term for square yards at a time"'"*". At that time, seagrass was seaweed or sea plant and rehia v^as a type of jelly-lil

stew that was made by boiling marine plants Imore proposed harvesting it for export to London, where usually algael with tutu berries, the fruit of a wetland dried Zostera fetched between £7 10s and £10 per ton

plant [Conana spp I'"'. Seagrass leaves were also as a stuffing for mattresses and upholstered occasionally used by Maori to adorn items of clothing. furniture"' "'. This suggestion does not appear to have

Hamilton in 1901 described widows wearing mourning been acted upon. Other accounts describe Zostera as caps [potae taua] that had veils made from seagrass'"'. "common in many of the lagoons and estuaries which Historical accounts by early European naturalists occur along the coast"'"', and as covering "extensive suggest that meadows were quite widespread at the areas of sheltered mud flats between the tides""".

end of the 19th century. Colenso in 1869 described Oliver in 1923 described extensive meadows of Zostera them as "very plentiful" and occurring in "many places in Parengarenga Harbour, Tauranga Harbour and

in the colony" from the top of the North Island to Golden Bay, Stewart Island'"'. According to him, Stewart Island'''"'. Leonard Cocl

Table 12.2

List of locations where seagrasses have been recorded in New Zealand

Location Description

Parengarenga Harbour"" Extensive tidal sand flats 142 km'l mostly covered in seagrass. Important feeding grounds for large fish

and bird populations

Muriwhenua Wetlands""' Includes Houhora (10.5 km'l and Rangaunu Harbours 174 km'l. Extensive tidal sand flats mostly

covered in dense beds of seagrass, supporting abundant mollusks, polychaeles, anemones, asteroids

and crustaceans. Important feeding grounds for large fish and bird populations

Whangarei Harbour'"-"' Lush seagrass beds present until late 1960s. Some recent recovery

Whangapoua Wetlands'"' Seagrass present on mud flats leal 4% of the area]. Significant site for shellfish gathenng

Waitemata Harbour'"' Seagrass meadows much reduced since 1960s, now in small abundance in a range of locations

Tairua Estuary'™' Around 1.25 km'' in 1995, covering ca 23% of the tidal flats

Whangamata Estuary'™' Around 0.51 km' in 1995, covering ca 18% of the tidal flats

Wharekawa Estuary'™' Around 0.50 km' in 1 995. covenng ca 32% of the tidal flats

Kaipara Harbour'"' Extensive mud flats and sand flats, but limited area of seagrass ""' Manul

temporally variable

Firth of Thames'"' Internationally important feeding area for waterfowl IRamsar Sitel. Around 0.3 km' of seagrass on

tidal flats of ca 85 km' Traditional food gathenng area. Important local fishenes for snapper and flounder

Kawhia Harbour'"' Seagrass beds often present on tidal sand and mud flats

''' Tauranga Harbour'"' Around 29.3 km' of seagrass remaining 119961. Decline of 34% overall from 1959 and 90% in subtidal

meadows. Important shellfishery, spawning and nursery areas for manne fishes

Mal(etu-Waihi Estuaries'"' Intertidal mud flats and sand flats have local areas of seagrass

Ohiwa Harbour'"™"' About 23.8 km' of intertidal flats with 1.1 km' of seagrass. Outstanding

importance as an area for traditional shellfish collection

Ahurin Estuary and Wetlands'^ Patches of seagrass in the marine reaches of the estuary, along with

Ruppia and green algae. Important nursery for fish. High diversity and abundance of invertebrates,

especially cockles

Te Angiangi Manne Reserve-East Patches of seagrass on coastal reefs. Marine reserve

Te Tapuwae Rongokako Patches of seagrass on coastal reefs. Marine resen/e

Pauatahanui Inlet'^" Large areas of Zostera capricorni on the banks of the inlet near deltas of Horokiwi and

Pauatahanui streams

Farewell Spit'"'*" Extensive areas of sand and mud Hats. Large areas of seagrass.

Internationally important area lor waterfowl IRamsar sitel New Zealand 137

storms and washed onto beaches or swept out to sea in grounds for wading birds, which were hunted these areas. extensively at the time for food and sport''"'". At least

In the nnajor South Island city. Chnstchurch, mud ten families had made their living harvesting shrimp flats of the Avon-Heathcote Estuary were reportedly from what they referred to as "shrimp grass""". By

"covered In great expanses of eelgrass IZosferaj" prior 1952, the seagrass had disappeared almost completely, to European settlement"". Early photographs clearly with only a few, very small patches remaining in the show dense meadows lining the sand banks of the main northern channel of the Avon River'"". Since then, channels'""' and accounts described seeing eels patches have waxed and waned in abundance. By 1970 feeding in "lush paddocks" of seagrass that grew in the Zostera had almost completely disappeared'^"". In deep channels"". Later records document the rapid 1981, small patches covered around 1A percent of the disappearance and stuttering recovery of Zostera in the tidal flats, but these disappeared later in the same year estuary. By 1929, the "lush paddocks" had been with almost complete defoliation occurring in many

reduced to sparse, small patches'"'. Loss of the areas'"'. The most recent surveys, in 1999, show a total meadows was associated with the decline of small area of around 0.137 km' that comprises around eight fisheries for shrimp and periwinkles in the estuary and consolidated patches'"". caused a "severe and rapid degradation" of feeding Seagrass losses have also been reported in other

Location Description

Whanganuilnlet'^'"' Large seagrass beds 18.6 km'l, especially in the northern part of the inlet.

Important nursery for manne fishes. Marine reserve

Waimea Inlet'"'" Extensive bar-built estuary. Around. 0.28 km^ of seagrass

Parapara Inlet'"' Zostera capricorni on silt deposits on the rock platform and on mud flats

Moutere Inlet'"' Large mud flats with extensive beds of Zostera capncorni and shellfish.

Important nursery for manne and freshwater fishes

Waikawa Bay (Queen Charlotte]'"' Patches of Zostera capricorni present

Wairau Lagoons"'-'" Extensive areas of algae, Ruppia megacarpa and some Zostera. Nursery

habitat for manne and freshwater fishes ''^^ Kaikoura Peninsula'*' Zostera capricorni present on coastal siltstone reefs at Wairepo flats and l^ludstone Bay

Karamea Estuary'^" Mud flats with extensive areas of seagrass and large densities of invertebrates

Saltwater Lagoon'^" Bare or sparsely vegetated tidal mud flats

OkantoLagoon'^''"' Middle reaches of lagoon dominated by Zostera. upper reaches charactenzed by dense beds

of Ruppia, Lepidena and Nitella

Avon-Heathcote Estuary, Patches of seagrass grow between low and mid tide close to the Avon Channel. Seagrass more

Chnstchurch'^''"' abundant pnor to 1929. Nationally important area for waterfowl. Among the most important food

gathenng sites for South Island Maon in pre-European times

Akaroa Harbour"" Extensive areas of seagrass on tidal flats at Duvaechelle and Takamatua Bays

Purau Bay, Lyttieton Harbour"" Patches of seagrass

Brooklands Lagoon'""' Scattered, large circular patches of Zostera capricorni prior to 1978, None recorded in 1991

Otago Harbour'""' Around 0.8 km' of seagrass on tidal flats at Harwood

New River Estuary"" Extensive mud flats with seagrass. Important source of iiaimoana. Nationally important wildlife area

Awarua Bay"" Extensive mud flats with seagrass. Important source of kaimoana. Nationally important wildlife area

Toetoes Harbour"" Mud flats with extensive areas of seagrass and large densities of invertebrates. Nationally

important wildlife area

Freshwater"" Mud flats beyond the support seagrass

Paterson Inlet. Stewart Island""

Moeraki Beach"" Patches of seagrass on coastal reefs

Mahurangi Harbour"" Around 0.03 km' in 1999 in a single meadow.

Whangateau Harbour"" Around 0.33 km' in 1999 consisting of two main beds in the southern arm

Whitianga Harbour""' Around 0.5 km' in 1995, occupying ca 0.6% of the estuary area

Manaia Harbour""' Around 0.27 km' in 1995, covering ca 7.5% of the estuanne flats

Te Kouma Harbour"™ Around 0.05 km' in 1995, covering ca 2% of the tidal flats

Otahu Estuary""' Around 0.002 km' in 1995, covenng ca 0,4% of the tidal flats 138 WORLD ATLAS OF SEAGRASSES

parts of the country. Zostera was reputedly once very been implicated in the disappearance of extensive areas '". abundant in Waitemata Harbour, the location of New of seagrass'"

Zealand's largest city, Auckland (population ca 1 Armiger reported the widespread die-back of

millionl. Before 1921. seagrass dominated large areas seagrass throughout New Zealand during the 1960s"".

of Hobson Bay and Stanley Bay, but by 1931. it had all In 196^, she isolated a slime mold from some of the but disappeared'™ '". Powell'^" associated this loss with affected populations that resembled Labyrinthula

marked reductions in catches of snapper and other zosterae""', the pathogen responsible for the infamous

carnivorous fishes. At the time, he speculated that "in wasting disease epidemic in North Atlantic Zostera respect to depletion of harbour fishing grounds during the 1930s'""'. Subsequent collections and

generally [loss of seagrass] may be a more important observations showed that the mold and symptoms of factor than either over-fishing or assumed harbour die-off were present throughout both the North and pollution". This hypothesis has been given greater South Islands'^". Other studies have reported sporadic ''^'". weight by research that suggests an important nursery outbreaks in some populations'* Curiously, the first

role of seagrasses for juvenile snapper'^''. recorded disappearance of seagrass meadows in New

Extensive meadows in the Tamaki Estuary, Zealand, from Waitemata Harbour and the Avon- Howick Beach, Okahu Bay, Kawakawa Bay, Torpedo Heathcote Estuary, occurred at much the same time as

Bay and Cheltenham in the Auckland district that the epidemic and corresponded were present during the early 1960s disappeared by with reports of the large-scale disappearance of

the 1 980s'" "^ Well-developed stands of seagrass also Zostera in South Australia'"'. occurred on Te Tau Banks and along the northern tidal

flats of Manukau Harbour in the early 1960s"". PRESENT THREATS

Descriptions at the time referred to "splendid Zostera There has been no recent assessment of the condition

fields of the Manukau Harbour... in some places up to of New Zealand's estuaries and, therefore, of a mile across""". Most of these areas had also contemporary threats to seagrass habitats. New

disappeared or were severely reduced in size by the Zealand is relatively sparsely populated lea 3.8 million

early 1980s'"'. people in a total land area of 268021 km') so that.

Further north, "lush beds" of seagrass on mud although most of its estuaries have settlements

flats in Whangarei Harbour disappeared in the early nearby, only six are located within urban environments

1960s'"'". In Tauranga Harbour. Park recorded a that contain more than 80 000 people'"'. Estuarine

decline of around 1 5 km' (about a third of the total area habitats have, however, been progressively modified

of seagrassl between 1959 and 1996'"'. Subtidal since the times of Polynesian (ca 800 years agol and meadows were most affected, with just 0.A6 km' European (ca 200 years agol settlement. Land

remaining out of the i.79 km' present in 1959 la 90 clearance, shoreline reclamation, harbor development, percent reduction]. flood mitigation works and discharge of pollutants have The causes of these declines are generally had direct impacts. Less than 23 percent of the land

unclear They have variously been attributed to a range area of the country now remains in native forest with

of different human activities and natural events. In the significant areas converted to agricultural production

Avon-Heathcote Estuary, the loss was linked to the 151 percent! or plantation forestry (6 percent]'"'.

practice of "river sweeping" which began in 1925 to Sedimentation is the most widespread problem in

clear silt and plant growth that had accumulated in the New Zealand's estuaries. New Zealand is a

two rivers which feed into the estuary'"'. Large predominantly mountainous and hilly country, with

quantities of sediment were released during the 25 nearly half of the land mass at slopes steeper than 28

years that the sweeper operated, producing a muddy degrees. Its rivers carry a particularly high load of

sediment layer in the estuary up to 25 cm deep. suspended sediments as a result of the steep terrain

Untreated sewerage effluent and industrial waste from and relatively high annual rainfall'"'. Deforestation and

the rapidly growing city of Christchurch were also rural land management have exacerbated the delivery

discharged into the estuary at this time and may have of suspended sediments to coastal areas and many of

contributed to the decline"". In Waitemata Harbour, the New Zealand's larger estuaries are very turbid (light

disappearance of seagrass was attributed to waterfront attenuation coefficients up to 0.75/m'l, with compara-

construction, channelization of tidal streams and runoff tively high rates of sediment accretion. In some of fine sediments from surrounding land develop- northern estuaries, this has meant that the area of

ment'^"'. In Whangarei Harbour, a major cement works intertidal habitat has slowly been reduced by increases

discharged around 106000 metric tons of limestone in the area of mangroves and supratidal . washings each year into the surrounding waters. The Losses of seagrass habitat have been attributed to

discharge significantly reduced water clarity and has increased sedimentation and turbidity in a number of

V New Zealand 139

U. 22. a. 52, 561 estuaries and it remains the biggest for example, horse riding and four-wheel drive bikes challenge for restoration of submerged aquatic occasionally rip up rhizomes and roots leading to the vegetation. formation of large bare patches that can take longer

Large areas of plantation forest are now coming than one year to regrow. Heavy trampling (more than into production in New Zealand and harvests are ten passes in one areal across the seagrass flats has expected to double within the next ten years to more also been shown to cause trench formation and lasting than 600 km' per year The largest increases are likely damage, but it is unclear how widespread this is'"'. to occur in regional areas of the North Island Occasional, recurrent outbreaks of wasting

(Northland, Coromandel. East Cape, Hawkes Bay, and disease appear likely In New Zealand seagrass southern North Island!, and to include areas bordering populations. Further study is required to understand some of the most significant remaining areas of sea- the epidemiology of these outbreaks and, in particular, grass (e.g. Parengarenga, Houhora and Coromandel if they are exacerbated by human activities. In the first

Harbours]. It will be Important for industry and regional instance, this requires an understanding of the authorities to manage sediment and nutrient runoff resilience of different meadow types (e.g. large versus from this activity to avoid additional impacts on the patchy, persistent versus ephemeral! to outbreaks of ecology of these estuaries. the disease and the method of transmission of the

Nutrient enrichment from land-based sources is a pathogen from one location to another significant problem In some urban estuaries. Recurrent Nevertheless, there are positive signs that blooms of macroalgae in Tauranga Harbour and the seagrass meadows are slowly returning to some areas

Avon-Heathcote Estuary in Christchurch have been from which they had been lost. In Whangarei Harbour, attributed to nutrient loads from wastewater discharge improvements in water quality over the past two and urban runoff. No direct studies have been done of decades have led to the re-establishment of the effects of nutrient loading from these sources on seagrasses In areas from which they had disappeared. seagrass growth, although both estuaries have had Discharges of limestone washings into the harbor significant seagrass meadows in the past'''"'". Less ceased in 1983 and, since then, improvements in

Information Is available on nutrient loads to estuaries sewerage wastewater and other discharges have outside the major urban centers. The most widespread greatly increased water quality"". This pattern has sources of nitrates entering New Zealand rivers are been repeated in other estuaries as point sources of likely to be associated with effluent and runoff from pollution have been removed or have been better agricultural production"". It is unclear what impacts managed over the past 20-30 years. Regrowth of these diffuse sources have had on seagrass habitats. seagrasses in the Avon-Heathcote Estuary Is no doubt

In some areas, recreational activities have had attributable, in part, to improvements in water quality localized Impacts on seagrasses'^^ "'. In Otago Harbour, that have been made through upgrading treatment of

Figure 12.1

An example of changes in the historical distribution of seagrasses in New Zealand

Moncks Bay in the Avon-Heathcote Estuary, Chnstchurch at low tide in 1885 (left! and 2003 (nght!. The channel morphology has changed

considerably since 1885 and the once extensive intertidal sand banks have all but disappeared. Seagrass meadows, which can be seen

clearly as dark bands lining the sand banks in 1885, are no longer present. It is unclear whether the change in channel morphology

preceded the loss of seagrass or resulted from it, as the root and rhizomes of seagrass meadows trap and hold soft sediments in place. 0^, H 140 WORLD ATLAS OF SEAGRASSES

wastewater and urban runoff and ending disturbance of development of the regional coastal plans. Wetlands

river habitat'""'. Non-point sources of pollution and are specifically Identified as a "matter of national

urban stormwater, however, remain significant importance" in the RMA that must be taken Into problems for many estuaries. account when decisions are being made about resource use. Because of this, many freshwater and POLICY AND MANAGEMENT estuarlne wetlands are specifically listed as "areas of Seagrasses and other aquatic macrophytes are not significant conservation value" in existing and specifically protected by legislation m New Zealand, but proposed coastal plans, and are subject to relatively are provided for under a variety of resource man- strict development controls. In some instances, agement and conservation legislation. Responsibility regional authorities have used regulatory measures for the protection and management of coastal habitats such as estuarme protection zones to exclude

Is split among several national and regional damaging activities from sensitive environments. authorities. Regional authorities are also responsible for

The Resource Management Act 1991 (RMAI is an maintaining coastal water quality under the RMA and

overarching piece of legislation that governs the use of regulate land-based activities that can detrimentally most natural and physical resources (excluding affect water quality.

fisheries! In New Zealand. Under the RMA, regional The New Zealand Fisheries Act 1996 provides for authorities have principal responsibility for managing the "utilization of fisheries resources while ensuring

the use of coastal environments and are required to sustainabillty". This includes managing the current and prepare regional coastal plans as the strategic basis potential production of fisheries in New Zealand and

for guiding decisions about resource use In these their impact on the habitats that support them.

areas. Development activities within the coastal Although marine vegetation is not specifically mention-

marine area require approval ("resource consent") ed In the Act, It establishes environmental principles to from the local authorities under the RMA and must be guide the utilization of fisheries resources. These consistent with the provisions of the coastal plan. include the "maintenance of biological diversity" and

Priorities for coastal management were set by the the "protection of habitat of particular significance for

Minister of Conservation in the New Zealand Coastal fisheries management". Provisions allow for the pro- Policy Statement and these serve as a guide for tection of specific areas that are Important for local and

Case Study 12.1 opportunity to study the causes of rarity and A SEAGRASS SPECIALIST extinction In marine environments and to determine

what Impact (If any) loss of the North Atlantic limpet

An unusual seagrass specialist in New Zealand Is may have had on other species that live and feed in the small endemic limpet, Notoacmea helmsi seagrass meadows.

[scapba] (see drawing, right). This species appears

to occupy an almost identical niche to the North Atlantic species Lottia alveus. which reputedly

became extinct during the wasting disease epidemic : of the 1930s'^". Lll

Unfortunately, there have been no studies of 4nim

Its life history, so it is unclear it it is as specialized as

its North American counterpart and, although it was reportedly once widespread in New Zealand""', there - y i i IS no contemporary information on its distribution 1 i and abundance. The absence of detailed study also

means that there is some uncertainty about whether

Notoacmea helmsi [scapha] is a true species or Morphology and habit of the New Zealand seagrass limpet

simply a morphological variant of the larger Notoacmea helmsi [scapha]. estuarine limpet Notoacmea helmsi helmsF''°\

The New Zealand limpet provides a unique Source: Redrawn from Morton and Miller''"

tf I New Zealand Ui

customary fisheries Uaiapure], traditional fishing [mataitai] and for the protection of specific stocl

Legal protection of coastal waters is mostly administered by the Department of Conservation under the Marine Reserves Act 1971. Marine reserves contain the highest level of protection for natural marine environments in New Zealand; all species and habitats are protected from exploitation. There are currently 16 marine reserves in New Zealand that encompass around 7633.5 km^ However, only two of these contain significant areas of seagrass. Whanganui (WesthavenI

Inlet contains around 8.59 km' of seagrass'"' which are protected through a combination of a marine reserve and a wildlife management reserve that cover a total area of 26.^8 km^ Te Angiangi Marine Reserve, on the east coast of the North Island, also encompasses extensive stands of seagrass on intertidal platform reefs"". The exact area of seagrass in the reserve is not known, but in this open coast environment it is likely to be highly variable'". Pliotograpliers negotiating the tidal cfiannels near New Brighton in

The Wildlife Act 1953 and Reserves Act 1977, also the Avon-Heathcote Estuary in the early 1900s. The elevated intertidal administered by the Department of Conservation, have banl(s are clearly vegetated vi/ith extensive stands of Zostera. been used to protect intertidal habitats in some estuaries where there are important wildlife, scenic, has had similarly dramatic effects on the distribution scientific, recreational or natural values. and abundance of invertebrates, fishes and other

Five wetlands in New Zealand are registered estuarine wildlife that depend upon them, including under the Ramsar Convention as of special importance some species of commercial significance. The high to wading birds'^". Three of these contain coastal or turbidity of many New Zealand estuaries - caused by a marine environments that include areas of seagrass. combination of natural topography and changes in land

Farewell Spit, on the northwest of the South Island, use - means that restoration efforts are likely to be long contains an extensive area of intertidal sand and mud term and broad based, necessitating changes in land flats with Zostera caphcorni meadows'"'. It has been and catchment management. Immediate conservation protected as a Nature Reserve since 1938 and is a IS, therefore, best focused on the relatively few areas significant area for a variety of wading birds and where there are large, persistent meadows. There are, waterfowl. In particular, it is the site of the major however, promising signs of improving water quality in molting congregation of the native black swan, Cygnus a number of estuaries and of the recent expansion of atratus. More than 13000 swans have been recorded in seagrass habitats in some areas. the area, at densities of up to 1000 birds per km'""".

During these congregations, Zostera capricorni is the ACKNOWLEDGMENTS largest component of their diet. The two other coastal Preparation of the review; and attendance at the Global Seagrass

Ramsar sites are in the Firth of Thames in the North Workshop was supported by a Technical Participatory Programme grant

Island and Waituna Lagoon at the southern tip of the from the International Science and Technology Linkages Fund. Thanks

South Island. are due to Diane Gardiner [Ministry of Research, Science and

Technology), Megan Linwood IMinistry for the Environment! and Rick

CONCLUSION Pndmore [National Institute of Water and Atmospheric Research Ltdl lor

The collage of historical and contemporary information facilitating this. Valuable information from, and discussions with, Mark assembled in this review suggests strongly that Morrison, Anne-Maree Schwarz [NIWAj, Paul Gillespie [Cawthron seagrass habitats were once much more widespread in Institute], Stephanie Turner [Environment Waikatol and Don Les

New Zealand's estuaries. Their demise appears to be [University of Connecticut] improved the content of the manuscnpt. the result of a combination of disease and human activities that have reduced the quality of estuarine AUTHOR waters. Despite relatively limited information on the Graeme Inglis, National Institute of Water and Atmospheric Research ecological functions of these habitats in New Zealand, Ltd, RO. Box 8602, Christchurch, New Zealand. Tel: +64 [0]3 348 8987. historical information suggests that loss of seagrass Fax: +64 [0]3 348 5548. E-maiL g.inglisOniwa.cn.nz

\/ \

J 142 WORLD ATLAS OF SEAGRASSES

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20 Turner SJ, Riddle B [in review]. Estuarine Sedimentation and Heathcote Estuary, Christchurch: A study of the effect of urban

Vegetation - Management Issues and Monitoring Priorities. development around a tidal estuary. New Zealand Journal of Environment Waikato Internal Series 2001/05, Hamilton, New Marine and Freshwater Research 22:101-127.

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21 Cromarty P, Scott DA [1996]. A Directory of Wetlands in Estuary. Report to the Chnstchurch Drainage Board, Christchurch,

New Zealand. Department of Conservation, Wellington, New New Zealand.

Zealand. 44 Deely J [19921. The last 150 years - the effects of urbanisation. In:

22 Park SG [1999]. Changes in the Abundance of Seagrass Owen SJ ledl The Estuary - Where Our Rivers Meet the Sea.

[Zostera spp.l in Tauranga Harbour from 1 959-96. Environmental Christchurch s Avon-Heathcote Estuary and Brooklands Lagoon. Report 99/30, Environment Bay of Plenty, Tauranga, New Parks Unit, Christchurch City Council, Christchurch, New Zealand, Zealand. pp 108-121.

i New Zealand 1A3

45 Thompson EF [1930], An Introduction to the Natural History of the 58 Sagar PM, Schwarz A-M, Howard-Williams C [1995]. Review of the

Heathcote Estuary and Brighton Beach, Unpublished MSc thesis, Ecological Role of Black Swan ICygnus alratusl. NIWA Science and

Canterbury College, Christchurch, New Zealand. Technology Series No. 25, NIWA Christchurch.

46 de Their W [1976], Sumner to Ferrymead: A Christchurch History 59 Carlton JT, Vermeij GJ, Lindberg OR, Carlton DA, Dudley EC [1991].

Pegasus Press, Christchurch, New Zealand The first historical extinction of a marine invertebrate in an ocean

47 Knox GA [1992], The Ecology of the Avon-Heathcote Estuary, Report basin: The demise of the eelgrass Impel Lottia alveus. Biological for the Christchurch City Council and Canterbury Regional Council, SuHedn 180: 72-80.

48 Bruce A [1953], Report on a Biological and Chemical Investigation 60 Powell AWB [1978] New Zealand l^ollusca. Collins, Auckland, New of the Waters of the Estuary of the Avon and Heathcote Rivers, Zealand.

Christchurch Drainage Board Report, Christchurch. New Zealand. 61 Knox GA. Bolton LA, Sagar P [1 978]. The Ecology of Westshore

49 Cameron J [1970], Biological aspects of pollution in the Heathcote Lagoon. Ahuriri Estuary, Hawkes Bay Estuarine Research Unit

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50 Hounsetl WK [1935], Hydrographical observations in Auckland 62 Knox GA, Bolton LA, Hackwell K [1977]. Report on the Ecology of

Harbour Transactions of the Royal Society of New Zealand 64: the Parapara Inlet, Golden Bay Estuarine Research Unit Report No,

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Auckland and l^anukau Harbours, Transactions of the Royal 63 Davis SF [1987], Wetlands ol National Importance to Fisheries. Society of New Zealand b6: 354-401, Freshwater Fisheries Centre. MAFFish. Christchurch. New Zealand.

52 Dromgoole Fl, Foster BA [1983], Changes to the marine biota of the 64 Stephenson RL [1977]. Waikawa Bay IQueen Charlotte Sound): An

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wasting disease of eelgrass, Zostera marina. Canadian Journal of 66 Knox GA, Fenwick GD, Sagar P [1976] A Preliminary Investigation Botany 70: 2081 -2088 of Okarito Lagoon. Weslland. Estuarine Research Unit Report No.

55 Griffiths GA, Glasby GP [1985]. Input of river-derived sediment to 5. Estuarine Research Unit. University of Canterbury, New Zealand.

the New Zealand continental shelf: I Mass. Estuarine. Coastal and 67 Inglis G. Personal observations.

Shelf Science 2] -m-ni 68 Knox GA, Bolton LA [1978]. The Ecology of the Benthic Macroflora

56 Healy WB [1980]. Pauatahanui Inlet: An Environmental Study D5IR and Fauna of Brooklands Lagoon, Waimakariri River Estuary.

Information Series 141. New Zealand Department ol Scientific and Estuarine Research Unit Report No. 16. Estuarine Research Unit.

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Otago Harbour, New Zealand. Unpublished MSc thesis. University

of Otago, New Zealand.

Cfy 144 WORLD ATLAS OF SEAGRASSES

13 The seagrasses of THAILAND

C. Supanwanid

K. Lewmanomont

coastline of Thailand is 2583 km along the Gulf sandy or muddy sand substrates from the upper littoral

Theof Thailand and the Andaman Sea, and coastal to subtidal areas. Two species occur only in the Gulf of habitats support abundant populations of Thailand: Halophila m/norwhich grows on muddy sand

commercial fish and associated nearshore fisheries. in the intertidal zone and Ruppia maritima in mangrove

Seagrasses occur in many locations along the Thai areas or brackish water ponds. Cymodocea serrulata, shoreline. The occurrence, community structure and which grows on muddy sand, fine sand or sand with biomass of seagrasses have been studied at different coral rubble substrates in the intertidal zone, occurs in

locations in 19 provinces along the coastal areas of the both regions but is mainly distributed along the

Gulf of Thailand and the Andaman Sea. Among the 12 Andaman Sea coastline. Two species are found in the

species of seagrasses found in Thailand, Hatophila Andaman Sea and not the Gulf: Cymodocea rotundata,

avails is the most widely distributed, because of its which occupies the lower littoral zone on muddy sand

ability to grow in different habitats. Enhalus acoroides, area or sandy bottom mixed with dead coral fragments

the largest species, is also common in the major and Syringodium isoetifolium which occurs densely in

seagrass areas. Seagrasses are more abundant in the subtidal areas on fine sediment.

Andaman Sea than in the . A total of 68.5 km' along the coast of Thailand is known to be covered by seagrasses, but actual BIOGEOGRAPHY coverage must be much greater given the lack of

Most of the seagrass beds are multispecies beds measurements in 11 of the 2U locations in Table 13.1.

located in enclosed or semi-enclosed embayments Seagrass distribution is more extensive in the Andaman

from the intertidal area to 5 m in depth depending on Sea than in the Gulf of Thailand. seagrass species, chemical and physical factors. The four most important seagrass beds in

Distribution and habitat of the 12 seagrass species in Thailand are Head Chao Mai National Park, in Trang

Thailand is summarized in Table 13.1, Seven species province on the southern coast of the Andaman Sea and

are widespread in both the Gulf of Thailand and the just north of Malaysia, Ko Talibong ITalibong Island).

Andaman Sea. Enhalus acoroides occurs in brackish also in Trang province, Kung Krabane Bay, in water canals down to the lower intertidal and subtidal Chanthaburi province on the eastern coast of the Gulf of zones on mud, muddy sand and sandy coral substrates; Thailand near to Cambodia, and Ko Samui (Samui

Thalassia hemprichii grows on muddy sand or Island], in Sural Thani province, and part of the

fragmented dead coral substrates in the upper littoral southern coast of the Gulf of Thailand.

zone or coral sand substrate in subtidal areas; The seagrass beds at Haad Chao Mai National Halophila beccarii grows on mud or muddy sand Park, Trang province are the largest of these seagrass

substrates in estuarine and coastal areas in the beds and cover 18 km^ with the highest species

intertidal zone; Halophila decipiens was previously diversity for a single area in Thailand"". The beds cover

thought only to occur in waters 9-36 m in depth but has a small area around a peninsula called Khao Bae Na

been found in the intertidal areas where it is exposed and a larger area between the islands of Ko Muk and

during low tides; Halophila ovalis is found growing on Laem Yong Lum on the mainland. There are nine

various substrates such as mud, muddy sand and dead species in this area; Enhalus acoroides, Thalassia

coral fragments in the upper littoral to subtidal areas; hemprichii, Hatophila decipiens, Halophila ovalis,

Haiodule pinifolia and Halodule uninervis both grow in Halodule pinifolia, Halodule uninervis, Cymodocea Thailand 145

rotundata, Cymodocea serrulata and Synngodium

isoetifoiium"" . Halophiia decipiens Is considered to be Rayong a deepwater seagrass species in Thailand, However " ,»Chanthaburi this species occurs in the intertidal zone at Khao Bae • ,Tral Kiiiti; KruhiJiii- Ba\

Na and pure stands of Halophila decipiens are A4YANMAR •, Khan i '>.' 'Prachuab Khm therefore exposed during low tide down to the depths of 5 m" '". Until recently the only available information on the seagrass beds at Haad Chao Mai National Park was III J,/ • Chumphon qualitative and restricted to the intertidal zone, but in Ranong 2000 the distribution and biomass of seagrasses over i^ the entire subtidal and intertidal bed was t* Kii Samui investigated"^'. biomass was highest at shallower The (ialf uf ThailuuJ depths l<2 m) all along the coastline. Enhalus _^ lhanvnarat' acoroides was the most abundant species, followed by Halophila ovalis and Thalassia hemprichii. Both ^1 J Trang ,PI Halophila ovalis and Thalassia hemprichii were Haad Chao Mai ,* dominant at the upper intertidal area and formed Nalional Park Pattani Libony Island monospecific patches in sand dunes and tide pools Ko Uilibong • ^ respectively. Average above-ground biomass of 50 100 150 Kilometers seagrasses in the intertidal area (15 g/m'l was 1.5 times greater than the biomass of subtidal seagrass beds (10 g/m'l. Enhalus acoroides was the most Map 13.1 dominant species in the subtidal and lower intertidal Thailand zones'"'. The sedimentation rate inside the Enhalus acoroides beds was greater than those inside the IS limited to 2.5 m"". At the eastern end of the island, Thalassia hemprichii and Halophila ovalis beds seagrasses grow on muddy flats and are exposed to the because of the shape and size of the Enhalus acoroides air during low tide. Nine seagrass species were found: plants"^'. It has been suggested that distribution of Enhalus acoroides, Thalassia hemprichii, Halophila seagrass beds in this area is primarily controlled by the beccarii, Halophila ovalis, Halodule pinifolia, Halodule physical conditions of the local environment, principally uninervis, Cymodocea rotundata, Cymodocea serrulata the roughness of weather during the monsoon season and Syringodium isoetifolium"". Enhalus acoroides and and the amount of shelter available at different Halophila ovaliswere the dominant species in intertidal locations"". This is also true for the seagrass beds at flats while Halophila ovalis was widely distributed in Ko Talibong. The strong southwest waves during the the subtidal area to the southeast of the island. monsoon season (May-Octoberl induces instability of In the Gulf of Thailand, two major seagrass beds bottom sediments and high turbidity preventing are located in the almost enclosed Kung Krabane Bay seagrass settlement and growth in the area directly in Chanthaburi province and Ko Samui in Thani facing offshore waters"". Consequently seagrasses province" '*". Kung Krabane Bay has a small narrow only flourish in areas sheltered by the offshore islands. opening to the sea and an area of approximately 1 5 km'

At the muddy flat of Ko Talibong. 15 km from the which is surrounded by mangroves and shrimp ponds. southern end of the Haad Chao t^ai National Park bed, Five species of seagrasses grow here: Enhalus 7.0 km^ of nine seagrass species are distributed along acoroides, Halophila decipiens, Halophila minor, the northern, eastern and southeastern coasts of this Halophila ovalis and Halodule pinifolia, and cover "'". island. This bed is very important as a feeding ground 7.0 km'" The deepest part of this bay does not for the dugong IDugong dugonf"'. One hundred and exceed 6 m. Enhalus acoroides and Halodule pinifolia twenty-three dugongs were found in Haad Chao Mai were the two dominant species among the five'".

National Park and Ko Talibong seagrass beds in 2001. Ko Samui is the largest island on the west coast with the largest herd size being 53 dugongs in the Ko of the Gulf of Thailand and a major destination for

Talibong seagrass bed'"". foreign tourists. Five species of seagrasses grow in

Compared to the seagrass bed at Haad Chao Mai beds that almost completely surround the island:

National Park, the seagrass bed at Ko Talibong is highly Halodule uninervis, Halophila minor, Halophila ovalis, affected by siUation from the Trang River. These Halophila decipiens and Enhalus acoroides cover a seagrasses grow in a highly turbid environment with a total area of 7.7 km' and grow in association with transparency of about 1-2 m on mud and muddy sand corals, mainly Acropora spp. and massive species of substrates. As a result the maximum depth of seagrass coral, scattered around the island. Most of the seagrass 1A6 WORLD ATLAS OF SEAGRASSES

Table 13.1

Occurrence of seagrass species ir Tliailand

Province/major Se agrass species No. of Area

seagrass area Ea Th Hb Hd Hm Ho Hp Hu Cr Cs Si Rm species Ikm'l

Chop Buri / / / / / / 6 id

Rayong / / / / / 5 Id

Makampom Bay / 1 2.5

Chanthaburi / / / / / / 6 id

Kung Krabane Bay / / / / 5 7.0

Trat / / / / / / / 7 Id

Phetchaburi / 1 Id

Prachuab Khiri Khan / / 2 Id

Chumphon 1 Id

Surat Thani / / / / / 7 id

Ko Samui / / / / 5 7.7

Nakhon Si Thammarat / / / / i id

Songkhla / / / h Id

Pattani / / / / 5 4.2

Ranong / / / / / 7 1.2

Phangnga / / / / / / / / / 10 4.0

Krabi / • / J / / / 9 10,0

Phuket / / / / / / / / 10 4.7

Trang / / / / / / / / / / 10 27.1

Haad Chao Mai National Park / / / / / / / / 9 18.0

Ko Talibong / / / / / / / / 9 7.0

Satun / / / / / 5 0.06

Phatthalung / / 2 id

Narathiwat / / 2 0.04

Notes Ea Enhalus acoroides, Th Thalassia hen pnchii. Hb Halophil 3 becca r//; Hd Haiophita di cipiens Hnr Halophila minor. Ho Halophila ovalis,

Hp Hatodule pmihiia. Hu Hatoduk uninen/is, Cr Cymodocea rot mdala. Cs Cymodo cea Si rrulala Si Synngodium isoetifolium, Rm Roppia

maritima.

id insufficient data.

Source: Various sources'"".

areas were formed outside tfie area of living corals or Lewmanomont reported the occurrence of seagrasses

on reef flats inside tfie coral reef. Enhalus acoroides belonging to Halophila, Enhalus and Cymodocea in the grows on coarse substrates ranging from medium and mangrove areas'"'. Christensen and Anderson found

coarse sand to coral rubbles at a deptfi of 0.5-1.0 m. two seagrass species in Surin Island in 1977"". Two

Halodule uninen/is, l-lalophila ovalis, Halophila minor species were recorded in Koh Kram in Chon Buri

and Halophila decipiens are distributed on fine to province'". After this, many reports were published on

medium sand at 2.5-7.0 m in depth.'" the occurrence, community structure, biomass and area of seagrasses. Many studies on the ecology and biology

HISTORICAL PERSPECTIVES of seagrasses have been initiated under the ASEAN- "^*'. The first report of Halophila ovalis and Halodule Australia Ivlarine Science project since 1988"

uninen/is in Thai water was made in 1902 when For Thai people, the main importance of

Halophila decipiens was also described as a new seagrasses is their role as fishing grounds and as species. There were no further reports until 1970 when habitats for many commercially important species and

den Hartog found five species in Thailand: Cymodocea endangered marine mammals, but the value of

rotundata, Thalassia hemprichii, Halophila ovalis, seagrasses to provincial and national economies has

Halophila ovata and Halophila decipien^"'. In 1976, not been quantified. Indirect uses of seagrasses in Thailand H7

Thailand include their role in coastal protection and as maintain a unique physical environment in terms of nursery grounds for marine species. water motion and sedimentation which protects the Before 1999 there was no information on the coastline from the adverse effects of high wave action importance of seagrasses in coastal protection in during the monsoon season"^'.

Thailand. Then studies on the water flow and Thai seagrass beds are a nursery ground for hydrological factors in seagrass beds at Haad Chao Mai juvenile fishes and other marine animals. At Haad Chao National Park were conducted. The studies showed that Mai National Park, 30 families of fish larvae have been the Intensity of bottom water movement in seagrass recorded in the nearshore seagrass bed. The beds at lower depths was less than that at the upper abundance of fish larvae in the seagrass bed, at 2 06^ depths. This study demonstrated the effectiveness with individuals/1 000 m', was higher than in open sandy which Enhatus acoroides beds retard the intensity of areas, with 1217 individuals/1 000 ml Economically water motion: current speed inside the Enhatus important fish larvae found in this area were acoroides beds was 15 cm/s on the seafloor and 25 Carangidae, Nemlpteridae, Engraulidae, MuUldae and cm/s at 0.5 m in depth. This was a slower movement of Callionymidae'"'. At Haad Chao Mai National Park water than inside the other seagrass beds, and over seagrass bed, juveniles of the Malabar grouper, bare sand where currents speeds were 22.5 cm/s and Epinephelus malabaricus, were collected by small fish

35 cm/s on the seafloor and at 0.5 m depth, respectively. traps and cultured in net cages in the canals near the

The width and length of Enhatus acoroides blades is the seagrass bed'"'. Twenty-two species of juvenile fishes greatest among the seagrass species of Thailand, and were reported in the seagrass bed at Kung Krabane the blades not only greatly reduce the rate of water flow Bay, Chanthaburi province. Among these, Serranldae under and over the meadow but also induce a higher are the most abundant and are also the most important sedimentation rate as a result. In this way, the seagrass species for fisheries. From October to December, beds at Haad Chao Mai National Park create and fishermen collect juveniles of Serranldae species

Case Study 13.1 weight, 13.0 kg wet weight/day'^". Recently, other

THEDUGONG A FLAGSHIP seagrass species were found in the stomach content

SPECIES of dugongs in Trang province. The species included Halodute pinifotia, Halodute uninervis, Hatophila In Thailand, most fishermen and local people know ovatis, Cymodocea rotundata. Cymodocea serrutata.

that seagrass is an important food for the dugongs Synngodium isoetifolium, Thatassia hempnchii and

iDugong dugon]. The dugong in Thailand is an Enhatus acoroided'^^\

endangered species and is protected under the Thai The dugongs in the Andaman Sea are a Fishery Act 19-17. flagship species based on their specialized relation-

Before the first aerial survey for dugong in ship with seagrasses and they are further evidence 1992, not many Thais knew what dugongs and of the value and importance of the seagrass

seagrasses were. During the first survey in 1993, ecosystem. Recent surveys have shown that more

dugongs were found near the seagrass bed in Trang than 60 percent of the people along the Andaman Province and the Royal Forestry Department Sea appreciate the Importance of the dugongs and

announced that this was the last herd of dugong in seagrasses'^".

Thailand'^''. However, dugongs may still exist on the

eastern coast of the Gulf of Thailand'^". Fishermen in Rayong province have seen dugongs and their

feeding trails on small seagrass species'^".

More dugong feeding trails on l-lalophila ovatis

at Haad Chao Mai National Park were reported In 1996"^'. At that time. Thai people believed that dugongs preferred feeding on small seagrass

species. In 1998, the study on dugong grazing on

Halophita ovatis beds at Haad Chao Mai National

Park was carried out. It was reported that in a 100 x 100 m quadrat, one dugong could produce U.9

feeding trails 15.1 mVdayl. The estimated grazing

rate of l-lalophita ovatis by a dugong was 1.1 kg dry Dugongs and seagrass on a Thai stamp. 148 WORLD ATLAS OF SEAGRASSES

lapproximately 2.5 cm in length] in the morning using HISTORICAL LOSSES

scoop nets, and culture them In net cages until they It is very difficult to estimate the seagrass loss in

grow to marketable size, when each Individual weighs Thailand because there are no reports on historical

more than 0.8-1.5 kg''*'. coverage or loss. Most of the studies on seagrasses in

Seagrass beds in Thailand are very important Thailand were conducted recently and over very short

areas for fisheries, over and above their role as nursery periods of one to two years. There has been no long- areas, with both demersal and highly mobile species of term monitoring in the country. Even the present

fish being harvested from seagrass areas throughout seagrass coverage cannot be completely estimated.

the country. At least 318 species representing 51 However there is evidence showing that a small

families have been identified in seagrass beds in ASEAN seagrass bed at Khao Bae Na in Haad Chao Mai countries. They have economic value mainly as food and National Park has been covered by sand.

aquarium specimens"". In Thailand the diversity of fish Khao Bae Na is a small embayment of flat sand

is lower in seagrass beds in the Gulf of Thailand (where which had a dense HalophUa ovalis meadow extending 38 species of fishes from 29 families have been over approximately 30000 m'' and served in the past as

recorded from six seagrass beds'"""'! than in the a feeding ground for dugongs. The feeding trails of Andaman Sea (where 78 species of fishes from i6 dugongs were clearly seen during low tide. Some families have been recorded from the seagrass beds at Cymodocea rotundata, l-1alophila decipiens and small Haad Chao Mai National Park]. Many species are very patches of Enhalus acoroides occurred In this area.

important in terms of economic value such as Tidal level of the meadow was about 1 .8 m above mean Epinephelus malabancus, orange-spotted grouper lower low water"". Since the monsoon season in 2000, {Epinephetus coioides], great barracuda [Sphyraena this seagrass bed has been covered with a high level of barracuda], squaretail mullet [Liza vaigiensis], brown- sediment. Only small patches of Halophila ovalis and

stripe red snapper {Lutjanus vitta], Russell's snapper Cymodocea rotundata have survived and their

iLutjanus russeliil. mangrove red snapper [Lutjanus distributions have been limited by the high

argentimacutatus], oriental sweetlips [Plectorhmchus sedimentation rate. It is thought that the dugongs have

orientabs], silver sillago [Sittago sihama] and Indian moved their feeding grounds to Ko Muk and Talibong mackerel iRastrelliger kanagurta]'"'. Island seagrass beds.

In addition to the fishes in the seagrass area, On 20 January 2002. damage to the seagrasses at

crabs and sea cucumbers are also important to Baan Pak Krok in Phuket by the use of mechanized

fisheries. Since 1998, local fishermen have been push seines was reported in the press, but the area

collecting sea cucumbers from many seagrass beds in affected was not estimated. The Natural Resource

summer, during low tide. After drying the sea Conservation Group of Baan Pak Krok requested the

cucumbers, the fishermen sell them to Malaysian government to strengthen law enforcement. There is

buyers. At present, three species of sea cucumber have other anecdotal evidence of damage to seagrass areas

been harvested, namely, . Holothuria in Thailand but it would be impossible to determine the atra and . Fresh sea cucumber actual loss. costs US$12-15 (500-600 Bahtl per kg while the dried

ones cost US$25 per kg'"'. Eighty percent of the crabs THREATS

exported from Thailand are portunids, mainly Portunus Seagrasses in Thailand are threatened by a '^" pelagicus, coming mostly from seagrass areas. combination of illegal fisheries and fishing practices,

Direct use of seagrass is less apparent in Thailand and land-based activities, especially mining. The

although the seeds of Enhaius acoroides are eaten by destruction of seagrass beds is caused by fishing gear Thai fishermen. They believe that someone who has a such as small-mesh beach seines and mechanized chance to eat the seeds of Enhalus acoroides will be push seines.

lucky. However, they do not like to harvest the fruits of Before 1992, the local fishermen in five villages

Enhalus acoroides for food because of the time near Haad Chao Mai National Park used mechanized

necessary to collect enough seeds. Local people in push seines that decreased the number of marine

some areas in Thailand use dry seagrass leaves and animals and seagrass area. Paradoxically the

rhizomes for the treatment of diarrhea. At present, fishermen's Income also decreased while the use of

extracts from many species are being screened for these Illegal fishing gears increased. They started to

biological properties. For example a group of research- fish by using dynamite and cyanide in the seagrass bed. ers from Kasetsart University has been testing crude After 1992. the Royal Forestry Department announced

seagrass extracts and conducting five bioassays [anti- the occurrence of dugong in Haad Chao Mai National

bacterial, antifungal, cytotoxicity, antialgal and toxicity Park, and a mass media campaign helped to spread

tests) on these extracts. awareness of dugong and seagrass conservation in Thailand 149

Thailand. Local organizations implemented dugong and seagrass conservation projects to persuade local fishermen to stop using beach and push seines in seagrass areas. They can now only use traps for fishing. One year later, the seagrass bed at Haad Chao Mai

National Park had increased in size and the fishermen's income had increased because of larger catches from within the protected seagrass areas. However, the Royal

Forestry Department still found mechanized push seine trails in other seagrass areas"".

In Thailand, tin mining is centered in Phuket,

Phangnga and Ranong provinces. It has been suggested that sediments from tin mining in Phuket cause chronic problems for seagrass beds in Phuket and Phangnga provinces. Mining activities have now decreased drastically in most areas, but the seagrasses are still affected by other activities, such as land development resulting in landfill, open topsoil on roads and construction on hill slopes"".

A major threat to seagrasses in Thailand is Dugong feeding trails on Halophila ovalis at Haad Chao Mai reduced water clarity in many areas resulting from National Park. upland clearing, development along rivers and destruction of mangrove forests.

LEGAL AND POLICY INITIATIVES

In Thailand, there are only two seagrass protected areas. These are Haad Chao Mai National Park and Libong Island Non-hunting Area. Haad Chao Mai

National Park is administered by the Royal Forestry Department under the auspices of the Marine National Park Division. Haad Chao Mai National Park was established in 1981 and encompasses 230.9 km' - 59

percent of the area is an aquatic zone. Hunting and collecting are forbidden since this is the largest seagrass bed with the highest diversity in Thailand. Libong Island Non-Hunting Area IKo Talibong Non-

Hunting Area) was established in 1 960. The only activity

restricted here is hunting. Seven square kilometers of

seagrass bed distributed in this area serves as a feeding ground for more than 53 dugongs. Most of the

officers of Libong Island Non-hunting Area are the local

people of the island. They not only protect the area from hunting but also help other local people understand the Seeds of Enhalus acoroides.

importance of seagrasses to the marine environment. There have been several other policy initiatives operatives declared the prohibition of trawlers,

designed, in part, to conserve seagrasses. In 1972, the mechanized push seines, purse-seines and nets in the

Ministry of Agriculture and Co-operatives declared that area along Phangnga Bay which includes Phuket,

all mechanized fishing gears were prohibited within Phangnga and Krabi coastlines.

3000 meters of the coastline in all coastal provinces. In In 1998, the Office of Environmental Policy and 1993, Trang Provincial Notification was empowered Planning proposed policies for the management of under Fisheries Act B.E. 2/.90 (Fisheries Act 19i7| seagrass resources including:

Section 32'^' to declare that trawlers, mechanized push accelerated management and control of water

seines, beach seines and gill nets were prohibited in pollution; Haad Chao Mai National Park seagrass bed and at Ko increasing efficiency in management of seagrass

Talibong. In 1997, the Ministry of Agriculture and Co- conservation through landuse planning; 1

150 WORLD ATLAS OF SEAGRASSES

support for studies on seagrass research and governmental organization in Thailand, the Yad Fon conservation; Association, has been deeply involved with local campaigns to heighten and improve public people, spreading knowledge and enabling them aw/areness of the importance of conserving to understand the importance and usefulness

seagrasses, at all levels of the community; of seagrass beds. At this stage, seagrass and review and adjustment of laws, regulations and dugong conservation are mostly concentrated in the enforcement concerning seagrasses so that they Andaman Sea. work more efficiently by recognizing the import-

ant roles of local authorities and communities; ACKNOWLEDGMENTS

the monitoring of the status and problems of the We are grateful to Dr FT Short and Dr R G. Coles for

seagrass beds, with the cooperation of central their great support. Sincere thanks go to Assistant Professor Dr C.

government, local authorities and local people"". Meksampan, P. Wisespongpand, S, Putchakarn, S. Wongworalak,

S. Pitaksintorn, K. Adulyanukosol, Assistant Professor Dr S.

So far seagrass monitoring, restoration and Satumanatpan and N. Suksunthon for their information and help.

conservation in Thailand has not been widely

successful in the long term because of a lack of AUTHORS funding and a suitable methodology. Law enforcement Chatcharee Supanwanid and Khanjanapaj LewmanomonI, Department

alone has not led to the successful protection of the of Fishery Biology, Faculty of Fishenes, Kasetsarl University, Chatujak,

seagrass ecosystem. It is necessary to involve local BKK 10900, Thailand. Tel: +66 (012 579 5575. Fax: +66 1012 940 5016, people through information and education. A non- E-mail: ffischsSku.ac.th

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1 LewmanomonI K, Deethae S, Srimanopas V [1991]. Taxonomy and species composition of seagrass beds along the Andaman

Ecology of Seagrass in Thailand Final report submitted to the Sea coast of Thailand. Phuket Marine Biology Center Bulletin 59:

National Research Council of Thailand, Bangkok (in Thail. 43-52.

2 Snmanobhas V (1980). Some marine plants of Koh Kram, Chon 12 Poovachiranon 5, Puangprasarn S, Yamarunpattana C [20011. A Bun. Manne Fishenes Laboratory Technical Paper WU22I2. Survey ol Seagrass Beds at Krabi Bay Abstract paper presented at

3 Phuket Marine Biological Center (1998). Seagrass Management and the Seminar on Fishenes 2001, 18-20 September 2001. Department

Dugong Consen/ation. 1998 progress report submitted to Fishery ol Fisheries, Bangkok (in Thai(.

Department, Bangkok (in Thai(. 13 Nakaoka M, Supanwanid C (20001 Quantitative estimation ol the

4 Sudara S, Nateekarnianalarp S, Plathong S (19921. Survival and distribution and biomass of seagrasses at Haad Chao Mai National

growth rate of transplanted seagrasses Habdule piniloiia and Park, Trang Province, Thailand. Kasetsarl University Fishery

Enhalus acoroides in different types of substrata. In: Chou LM, Research Bulletin 22: 10-22.

Wilkinson CR ledsl Third ASEAN Science and Technology Week 14 LewmanomonI K, Supanwanid C 120001. Species composition of Conference Proceedings, Voi6, Marine Science: Living Coastal seagrasses at Haad Chao Mai National Park, Trang Province,

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Kung Krabane Bay Report to Fishery Department Research seagrass beds at Haad Chao Mai National Park in Trang Province,

Conference, 16-28 September 1992. Fishery Department, Bangkok Thailand. In: Koike I led) Effects of Grazing and Disturbance by

(inThai(. Dugongs and Turtles on Tropical Seagrass Ecosystem. University

6 LewmanomonI K, Deetae S, Snmanobhas V (1996). Seagrass of of Tokyo, Tokyo, pp 1-16.

Thailand In: Kuo J, Philhps RC, Walker Dl, Kirkman H (edsl 16 Koike I, Nakaoka M, lizumi H, Umezawa Y, Kuramoto T, Komatsu T,

Seagrass Biology: Proceedings ol an International Workshop. 25-29 Yamanuro M, Kogure K, Supanwanid C, LewmanomonI K (1999].

January 1996, Rottnest Island, Western Australia. University of Environmental factors controlling biomass of a seagrass bed at

Western Australia, Nedlands, Western Australia, pp 21-26. Haad Chao Mai National Park, Trang, Thailand. In: Koike I (edi

7 Nateekarnchanalarp S, Sudara S (19921. Species composition and Effects of Grazing and Disturbance by Dugongs and Turtles on

distribution of seagrasses at Koh Samui, Thailand. In: Chou LM, Tropical Seagrass Ecosystem. University of Tokyo, Tokyo, pp 66-81.

Wilkinson CR (edsl Third ASEAN Science and Technology Week 17 Ostenfeld CH (19021. Hydrocharitaceae, Lemnaceae, Potedenaceae,

Conference Proceedings, Vol S, Marine Science: Living Coastal Potamagetonaceae, Gentianaceae (LimnanthemumI,

Resources. National University, Singapore, pp 251-260, Nymphaeaceae. In: Schmidt J (edl 1900-1916 Flora of Koh Chang. 8 Chumphon Fishery Center (19981 Coral Reef Observation Report. Bianco Luno, Copenhagen, pp 363-366.

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of the Study of Seagrass Management in Thailand. Office of Distribution and Biology of the Dugong [Dugong dugonl in Thailand.

Environmental Policy and Planning, Bangkok (in Thaii. Abstract paper presented at the Seminar on Fisheries 2001, 18-20

9 Phuket Marine Biological Center (19961. Seagrass Management and September 2001. Department of Fisheries, Bangkok.

Dugong Conservation. 1996 progress report submitted to Fishery 19 den Hartog C (19701. Seagrasses of the World. North-Holland

Department, Bangkok (in Thai). Publishing, Amsterdam.

10 Supanwanid C, Nimsantichareon S, Chirapart A 11998). The 20 LewmanomonI K [19761. Algal flora of the mangrove areas. In:

Biodiversity of Seagrass in Ranong Research Station Coastal Area, Proceedings of the First National Seminar of Ecology of Mangrove,

1997-1998. Report submitted to Kasetsarl University Research and Vol. 2, Part 2. National Research Council of Thailand, Bangkok, pp

Development Institute, Kasetsarl University, Bangkok (in Thaii. 202-213 (in Thail. Thailand 151

21 Chnstensen B, Anderson W [1977], Mangrove plants, 30 Sudara S, Satumanatpan S, Naleekanjanalarp S [1992].

seagrasses and benthic algae at Sunn Islands, west coast of Seagrass fish fauna in the Gulf of Thailand. In: Chou LM.

Thailand. Phuket Marine Biological Center Research Bulletin U: Wilkinson CR ledsl Third ASEAN Science and Technology

1-15. Week Conference Proceedings. Vol. 6. Marine Science:

22 Poovachiranon S [1989]. Survey on Seagrass in the Andaman Sea Living Coastal Resources. National University of Singapore

from Phuket to Satun Provinces Final report of ASEAN-Australia and National Science and Technology Board, Singapore,

Coastal Living Resources Project, submitted to Office of the pp 301-306.

National Environmental Board. 34 pp. 31 Putchakarn S. Personal communication.

23 Sudara S. Nateekarn|analarp S [19891. Seagrass Community in the 32 Sea Aueng S, Witayasak W, Lukanawakulra R. Pearkwisak W,

Gulf of Thailand. Final report of ASEAN-Australia Coastal Living O'Sullivan P [1993]. A survey of dugong in seagrass bed at

Resources Project, submitted to Office of the National Changvtfat Trang. In: The 3lst Kasetsart University Annual

Environmental Board. 68 pp. Conference. Kasetsart University, Bangkok, pp 363-368.

24 Fortes MD [1990]. Taxonomy and Distribution of Seagrasses 33 Naleekanjanalarp S. Sudara S [1994]. Dugong protection

in the ASEAN Region. Paper presented during the SEAGRAM 2 awareness: An approach for coastal conservation In: Sudara 5.

Advanced Training Course/Workshop on Seagrass Resources Wilkinson CR, Ming CL ledsl Third ASEAN-Australia

Research and Management, 8-26 January 1990, Quezon City, Symposium on Living Coastal Resources, 16-20 May 199i. Philippines. Department of Marine Science. Chulalongkorn University. Bangkok. 25 Naleekanjanalarp S, Sudara S, Chidonnirat W [1991]. Observation pp 515-525.

on the spatial distribution of coral reef and seagrass beds in the 34 Pitaksintorn 5. Personal communication.

Gulf of Thailand. In: Alcala AC ledl Proceedings ol the Regional 35 Supanwanid C [1996]. Recovery of the seagrass Halophila ovalis

Symposium on Living Resources in Coastal Areas. Marine Science after grazing by dugong. In: Kuo J, Phillips RC, Walker Dl, Kirkman

Institute. University of the Philippines, Quezon City, Philippines, pp H ledsl Seagrass Biology: Proceedings of an tnternahonal 363-366. Workshop, 25-29 January 1996, Rottnest Island, Western Australia.

26 Duangdee T [1995]. Identification and Distribution of Fish Larvae in University of Western Australia, Nedlands. Western Australia, pp Seagrass Bed at Haad Chao Mai National Park, Changwat Trang. 315-318.

MSc thesis, Kasetsart University. Bangkok (in Thai). 36 Mukai H, Aioi K, Lewmanomont K, Matsumasa M, Nakaoka M.

27 Janekitkarn S [1995]. Some Ecological Aspects of Fishes in the Nojima S, Supanwanid C, Suzuki T, Toyohara T [1999]. Dugong

Seagrass Bed at Haad Chao Mai National Park. Changwat Trang. grazing on Halophila beds in Haad Chao Mai National Park, Trang

MSc thesis, Kasetsart University. Bangkok [in Thai]. Province, Thailand: How many dugongs can survive' In: Koike I led]

28 Sudara S, Naleekanjanalarp S. Thamrongnawasawat T, Effects of Grazing and Disturbance by Dugongs and Turtles on

Satumanatpan S. Chindon»/iv»at W [1991]. Survey of fauna Tropical Seagrass Ecosystem. University of Tokyo. Tokyo.

associated viith the seagrass community in Aow Khung Krabane. pp 239-254.

Chantabun. Thailand. In-. Proceedings ol the Regional Symposium 37 Adulyanukosol K, Poovachiranon S, Natakuathung P [2001].

on Living Resources in Coastal Areas. University of the Philippines. Analysis of stomach contents of dugongs [Dugong dugon] from

Manila. Philippines, pp 347-352. Trang Province. F/stery Gazette 54(21: 129-137 [in Thai].

29 Poovachiranon S, Fortes MD, Sudara S, Kisviiara W, 38 Mines E [2000]. Population and Habitat Assessment of the Dugong

Satumanaptan S [1994]. Status oi ASEAN seagrass fisheries. In: (Dugong dugoni off the Andaman Coast of Thailand. Final report

Wilkinson CR. Sudara S. Ming CL ledsl Third ASEAN-Australia submitted lo the Ocean Park Conservation Foundation, Hong Kong.

Symposium on Living Coastal Resources, 16-20 May 19%. 39 Satumanatpan S. Sudara S. Navanugraha C [2000]. Slate of the

Department of Marine Science, Chulalongkorn University. seagrass beds in Thailand. Biologia Marina Mediterranea 7121:

Bangkok, pp 251-257. 417-420. 152 WORLD ATLAS OF SEAGRASSES

14 The seagrasses of MALAYSIA

J.S. Bujang M.H. Zakaria

Malaysia's coastline is around 4800 km long, policies governing the conservation and management stretching along the Malay Peninsula, Sabah of mangroves by the National Mangrove Committee''"' and Sarawak, bounding much of the southern and corals under the Fisheries Act 1985. However the

part of the . In and adjacent to this importance of seagrasses at local and national levels, coastline are three major coastal ecosystems - and from the standpoint of conservation, has received mangroves, coral reefs and, less well known, far less attention. There are no specific reserves or seagrasses. Corals are found on the outer edge of the legislation for seagrasses. Given the importance of

coastal zone while mangroves are on the inner edge. In seagrass as fisheries habitat, nursery and feeding

general, coastal areas between mangroves and corals, grounds in Malaysia, this neglected and relatively

from low-tide level to the coral reef fringe, form the lesser known resource must be afforded the same

habitats for seagrasses in Malaysia. Seagrasses are priority and be as well managed as mangroves and also found around offshore islands with fringing corals. corals to provide for future renewable resource

Here they are usually found in the outer region between utilization, education and training, science and the corals and the semi-open sea. The earliest account research, conservation and protection.

of seagrasses in the shallow bays all around the coast

of Peninsular Malaysia dates back to 1924'". ECOSYSTEM DESCRIPTION

Information on seagrasses is scattered and appears in The majority of seagrasses in Malaysia are restricted to

a number of books, scientific publications and sheltered situations in the shallow intertidal associated

monographs'''"'"'. These have been largely taxonomic in ecosystem, semi-enclosed lagoons and also in subtidal

nature and list habitats of at least seven species of zones. In these areas they sometimes form diverse

seagrasses: Enhalus acoroides (then referred to as extensive communities. The overview of the seagrass

Enhalus koenigii by Ridley and HolttumI, Halophiia distribution and description in this section is given

ovalis, Halophiia minor (referred to as Halophiia ovata separately for Peninsular and East Malaysia (Sabahl. by Henderson!. Halophiia spinulosa, Halodule uninervis We include specific examples to illustrate the types of

(then referred to as Diplanthera uninervis], Thalassia seagrass bed found in Malaysia. hempnchii and Ruppia mantima.

In recent years more research has been carried Peninsular Malaysia

out on seagrasses in Malaysia. Consequently there are Along the west coast, patches of mixed species

now a number of reports in the literature that describe seagrass communities usually occur on substrates ^" """' the extent and richness of flora'" and fauna'" in from the sandy mud to sand-covered corals in the Malaysian seagrass beds. Unlike other terrestrial extreme northern region along the coast of Langkawi

communities that can be lived in, managed or exploited, Island, Kedah, to the central region of Port Dickson. seagrasses offer only a few direct uses. The ecological Negri Sembilan"^', extending as far as Pulau Serimbun.

role and importance of seagrasses has not been fully "^'. The Port Dickson area, at Teluk Kemang, is

understood. Much more effort has been spent on the only area in mainland Peninsular Malaysia that has

quantifying and managing mangroves and corals. intertidal seagrass on reef platform. In the southern Mangrove reserves have been established and coral region, around the Sungai Pulai area, Johore, mixed

reefs are protected and conserved in marine parks and species seagrass beds exist at depths of 2-3 m on both marine protected areas. There are guidelines and sandy mud banks of the mangrove estuary'"' and

-T^^ Malaysia 153

w^ i04T 20 40 60 80 100 Kilometers Si) i' Til I lll\.l A Pengkalan Nangka ii I Uak-Uak 7°N • Pulau Pertientian Tanjung d ^' Putau Redang , Mengayau SULU St.i

,u„ga, ,a,u, MefChang , •7u„^„ Abdul Rahman Turtle Islands Marine Pari,s iiOUTII Pulau .:>T •^ Paka CHINA Gaya • I ^ Sungai Mengkabong . Sandakan •" - Kemasik ^^^ PENINSULAR Sepangar Bay MALAYSIA • Telaga Simpul Kemaman Pulau Tiga Sabah MALAYSIA Labuan Island LahadDatu " Sirail uf Pulau Tabawan —• • Kuata Lumpur Putau Liohay Pulau Ttnjyih Pulau Maganling'^ / Dulang

{3 PuUu Tioniun Teluk lAPort Dickson Kemang ^^ Pubu Bcsar-- ^ -Malacca Kalimantan Piii.iu Tiinj^;. INDONESIA Pulau Sipndan PuIju Tanjung "PiiijuSibii Scnmbur AdangDaral Mirramhong. Map U.2 I SINGAPORE INDONESIA Tanjung; Sabati (Sumatra) A dung Laul.^vX Biion

50 100 150 Kilometers islands with fringing coral reefs such as Pulau Sibu, Pulau Tengah, Pulau Besar and Pulau Tinggi"^ '^', Pulau Map U.1 Redang and Pulau Perhentian''" and Pulau Tioman"".

Peninsular Malaysia Seagrasses are usually found in the outer region between the corals and the semi-open sea. calcareous sandy mud subtidal shoals of Merambong"^', Tanjung Adang Darat"" and Tanjung East Malaysia

Adang Laut''"'. These subtidal shoals, at depths of The west and southeastern coasts of Sabah harbor

2-2.7 m, support nine species [Enhalus acoroides, mixed species seagrass beds in the intertidal zone Halophiia ovalis. Halophila minor. Halophila spinulosa, down to a depth of 2.5 m. Seagrasses grow on

Thalassia hemprichii. Cymodocea serrulata, Haloduie substrates ranging from sand and muddy sand to coral pinifolia, Haloduie uninervis, Synngodium isoetifolium] rubble. There are six areas of intertidal mixed of seagrasses. the highest species nunnber for any associations of seagrass and coral reef along the west locality in Peninsular t^^alaysia or East Malaysia'"'. coast at Bak-Bak, Tanjung Mengayau, Sungai Salut,

These beds measure 1-1.2 km in length and 100-200 m Sungai Mengkabong, Sepangar Bay and Pulau Gaya. in width according to estimates based on the visible The four isolated offshore islands of Pulau Maganting, portion exposed several times in a year by low tides. Pulau Tabawan, Pulau Bohay Dulang and Pulau

This is therefore probably the largest single seagrass along the southeastern coast have subtidal bed in Peninsular Malaysia. The south has a greater seagrasses growing on coral rubble'""""'^'. diversity of seagrasses than the northern region with In Sarawak, other than records of herbarium just three species [Halophila ovalis, Cymodocea specimens of Halophila beccarii, collected by Beccari in serrulata and Haloduie uninervis] in Tanjung Rhu and Sungai Bintulu" "", and Halophila decipiens collected at

Pantai Penarak in the north. Pulau Talang Talang, Semantan"''', nothing much is Intertidal areas of the eastern coastline are known about the seagrass habitats, distribution and devoid of seagrasses. Beds of two species, Halophila species composition. beccarii and Haloduie pinifolia, inhabit the fine sand substrate of the shallow inland coastal lagoons from BIOGEOGRAPHY Pengkalan Nangka, Kelantan, to Paka, Terengganu, Peninsular Malaysia while Haloduie pinifolia and Halophila ovalis inhabit a The distribution of seagrasses in Peninsular Malaysia '*""'. similar substrate type at Gong Batu and Merchang. has been detailed in various publications""''^ A Monospecific beds of Haloduie pinifolia were found at very broad distinction can be made between the

Kemasik, Terengganu, and pure stands of Halophila seagrass distribution of the west and east coasts. beccarii grew on the mud flat of the mangroves in Differences in the available habitats and prevailing Kemaman, Terengganu. Monospecific beds of Haloduie environmental characteristics along the east and west pinifolia, Halophila decipiens and mixed species coasts probably explain these distributions. On the west seagrass beds occur in the waters of the offshore coast seagrasses occur in the sandy mud sediments of

y^ir 154 WORLD ATLAS OF SEAGRASSES

shallow coastal waters while on the east coast the indicated extensive seagrass beds, many of the habitats

coastline is fringed with sandy to rocky areas which are le.g. the west coast of Peninsular Malaysia, East

not suitable for the growth of seagrasses. On the east Malaysia, Sabahl have been exploited or have coast seagrasses inhabit sandy mud lagoons, behind deteriorated to a greater or lesser extent as a result of

the sand ridges in areas sheltered from the open sea. coastal development, especially in the last 15 years"''*'. Seagrasses are also found around relatively calm Such phenomena would explain the present seagrass

offshore eastern islands with fringing reefs such as distribution, which is no longer extensive, and its patchy Pulau Redang, Pulau Perhentian, Pulau Tengah, Pulau distribution along the Malaysian coastline'""""". Sibu, Pulau Tinggi and Pulau Besan The west coast of Known uses of seagrasses were few. Burkill'" in Peninsular Malaysia does not generally experience his book, A Dictionary of the Economic Products of the

strong wave action, whereas the east coast is exposed Malay Peninsula, mentioned that Ridley recorded in

annually to the northeast monsoon from November to 1924 that the leaves of Enhalus acoroides were one of January'"'. the chief foods of the dugong, Dugong dugon, which

Clarity of water and sufficient light irradiance play was then common in Malaysia. Later the dugong

a significant role in the depth distribution of the became rare because it was hunted for meat and hide'".

seagrasses. Coastal waters are often turbid or high in Presently dugongs are found in areas with abundant suspended solids that limit the depth at which most seagrasses such as Pulau Sibu, Pulau Tengah, Pulau seagrasses grow, more so on the western coast of Besar and Pulau Tinggi on the east coast and around

Peninsular Malaysia than the east. This is reflected in Merambong, Tanjung Adang Darat and Tanjung Adang seagrass communities along the west coast which are Laut shoals of Sungai Pulai, Johore. Enhalus acoroides generally found inhabiting the shallow waters at depths fruits are edible""" and the coastal communities of

of less than A.O m. Seagrasses on the east coast, how- Sungai Pulai, Johore, still collect them for con-

ever, extend to deeper areas, 5.0-7.0 m. Seagrasses sumption. In addition the softer parts of Enhalus

will colonize greater depth if the water is clear By way acoroides form fibers that are made into fishing nets.

of comparison, in the clear water of the east coast the Ruppia maritima plants are used in fish ponds to aid in

depth limit for Hatophila decipiens ranged from 6 to the aeration of the water, and the milk fish [Chanos

24 m in the Sungai Redang Estuary and Cagar Hutang spp.l feeds on It. This functional role, though of Pulau Redang, Terengganu, respectively"" while in mentioned, has not been observed in Peninsular

the turbid water of the west coast, at Teluk Kemang, Malaysia, and is probably based on observations made

Port Dickson, it grows at 1.5-3.1 m'"'. in the fishponds of Java, Indonesia'^'. Ruppia maritima

is rare In Peninsular Malaysia"*'. Sabah, East Malaysia Other forms of utilization include using seagrass Seagrass distribution along the west and areas for fish |La(es calcarifer and Epinephelus southeastern coasts of Sabah was described by sexfasciatus] cage farming, for example at Pengkalan

Ismail In 1993"" and in the Tunku Abdul Rahman Nangka, Kelantan, and Gong Batu, Terengganu, which

Marine Parks IPulau Gaya, Pulau Mamutik, Pulau started in 1991, or oyster [Saccostrea cacullata] Sulug, Pulau Manukan and Pulau Sapil by Josephine farming as at Merchang from 1998"". Seagrass areas at

in 1997"'^'. Almost all seagrasses are associated with Pengkalan Nangka, Kelantan. Paka shoal, Terengganu, degraded coral reef, although a few are associated and Tanjung Adang Laut shoal, Johore, are used as with mangroves and habitats damaged through illegal collection and gleaning sites for food including fishes, fishing by explosive. There were no broad differences gastropods [, Strombus canarium],

regionally with respect to species distribution and bivalves {Gafrarium sp., Meretrixsp., Modiolus sp.\ and

composition. echlnoderms Isea cucumber e.g. Pentacta quadran-

gularis, Mensamaria intercedens]. Gleaning for food In HISTORICAL PERSPECTIVES seagrass areas associated with coral reefs is

In Peninsular Malaysia seagrasses [Enhalus acoroides, widespread in Sabah, East Malaysia.

Halophila avails] were apparently locally common all around the coast on muddy shores and areas exposed ESTIMATE OF HISTORICAL LOSSES ^ at low tlde"^ ' ". Historical accounts of the distribution There is no information in the form of historical maps

of seagrass species at three places in Sabah, Labuan or aerial photographs that can be used to determine Island, Sandakan and Lahad Datu, were given by den the loss of seagrass beds over time. The losses

Hartog in 1970"°'. Information on their abundance was reported here have been observed during repeated

not given. Ismail"" described seagrass habitats that visits to the various seagrass sites. On the west coast of

were already degraded by human activities In Sabah, Peninsular Malaysia, at Port Dickson, localized

East Malaysia, In 1993. Since the early reports, which depletion of seagrass (narrow-leaved Halodule Malaysia 155

uninervis and Enhatus acoroides] began In 199A. hydrocarbons were detected in the water and representing about 50 percent of the area originally sediments at Teluk Kemang''". present. This area was heavily utilized as a public The Sungal Pulai seagrass beds Tanjung Adang recreational area. At Teluk Kemang in 1997 there was Laut and Tanjung Adang Darat are diverse and

Intensive sand mining for reclamation activities in extensive, and were only discovered In 1991 and 199A mangrove swamps as part of the construction of a respectively, yet by 1998 they were at risk from port condominium. This caused the loss of Halophila ovalis development involving dredging of shallow passage- and Halodule pinifoiia In the subtldal seagrass bed of ways and land reclamation for new facilities, both

Teluk Kemang. Suspended particles in the water causing an Increase In the suspended solids in the settled on the leaves of the seagrasses, blocking light water column. Localized losses were observed with the for photosynthesis and causing considerable stress and death of sand-smothered HalophUa ovalis clearly mortality through burial. The presence of an oil visible. In addition dense overgrowth of the macroalgae refinery, intense shipping activity and frequent oil spills Gracilaria coronopifolia and Amphiroa fragiiissima

In the adjacent waters have also been suggested as caused the seagrasses In the area to die back. potential causes for the decline or loss of seagrasses However, recovery occurred with regrowth of sea- along the coastline of Port Dickson. Tar balls in grasses and the disappearance of the macroalgae. significant quantities, frequently washed ashore, were On the east coast at Pengkalan Nangka, Kelantan, evidence of oil spills. In addition, petrogenic the decline was the result of human activities such as

Case Study U.I THE SEAGRASS MACROALGAE COMMUNITY OF TELUK KEMANG

At Teluk Kemang, Port Dickson, Negri Sembilan, the ovalis occur at depths of 3.2 to 3.5 m. Ivlorphological

intertidal community consists of non-uniform differences are observed in Halophila ovalis in these

patches of mixed seagrasses and macroalgae on a two communities. Subtldal Halophila ovalis plants coral reef platform 1.0-1.5 m deep. Seagrasses grow possess much bigger leaf blades and more cross-

in various substrates, from sand-covered coral to a veins'^" than plants of the same species growing in

combination of silt, coarse sand and coral rubbles the Intertidal zone.

Isee photograph!. Halophila ovalis is dominant and Another conspicuous seagrass is Halophila widespread, interspersed with Thalassia hemprichii, decipiens \Nh]ch occurs at shallow depths of 1.5-3.0

Cymodocea serrulata. Enhalus acoroides and m'-"'. Halophila decipiens was previously thought to

Halodule pinifolia. Synngodium isoetifolium, a rare be a deepwater species growing at depths between

species here, occurs in patches in the sand-tilled 10mand30m"°-"-'". spaces amongst coral rubble areas, Macroalgae coexist with these seagrasses. The most common, and seasonal, macroalgae species are IChlorophytael Caulerpa sertularioides, Caulerpa prolifera, Caulerpa racemosa, Caulerpa

lentillifera: IPhaeophytae) Sargassum polycystum. Sargassum cnstaefolium, Sargassum ilicifolium and Padina tetrastomatica: and (Rhodophytae) Laurencia corymbosa and Jama decussato- dichotoma"''\ This intertidal community extends into

the subtldal zone to depths of 3.5 m with a clear

zonatlon of seagrass species that are confined to

sandy mud and silty substrates. Pure stands of Halophila ovalis and Halodule pmifolia with isolated

individuals of Enhalus acoroides occur at a depth of

1.5 m. Halophila decipiens grows in small patches at

a depth of 1.5-2.0 m in association with Halophila The Telul< Kemang seagrass macroalgae community on coral ovalis and Halodule pinifolia. Slightly deeper, at 2.0- reef platform, Seagrasses occupy the sand-filled spaces of the 3,0 m, Halophila decipiens forms a continuous coral reef platform, and macroalgae dominated by Sargassum meadow. Occasionally patches of pure Halophila spp inhabit the boulders and coral rubbles.

ferr 156 WORLD ATLAS OF SEAGRASSES

the dredging of sand for landfills wfiicfi fiave totally sediment movement during the northeast monsoon removed two shoals of Halophila beccarii and Halodule storms of October 1998 to January 1999. No recovery to

pinlfolia, representing 30 percent of the total seagrass the original areal extent has been observed yet. Mining

area. At Merchang and Kemasik. Terengganu, the effect of sand at Telaga Simpul, Terengganu, in March 1997,

of wind and resulting wave action on lagoon seagrass is for the shoreline stabilization and protection of Kuala

reduced by the sheltering presence of the sand ridges. Kemaman village, resulted in high total suspended

Despite this protection, 50-70 percent of Halodule solids in the water column and sedimentation pinifolia and Halophila ovalis seagrass beds were smothered the dense Halophila beccarii bed there. The severely damaged by intense winds, waves and bed was transformed to sparse and scattered patches

Case Study U.2 THE SUBTIDAL SHOAL SEAGRASS COMMUNITY OF TANJUNG ADANG LAUT

The subtidal shoal of Tanjung Adang Laut in the algae, such as Acanthophora spicifera, Amphiroa

Sungai Pulai estuary, Johore, is 1.5-2.7 m below rigida, Amphiroa fragilissima, Hypnea esperi and

mean sea level and is vegetated with seagrasses Ulva spp. lie loosely amongst the seagrasses.

Isee photograph]"". This shoal is one of the feeding Attached leg. Gracilaria coronopifolia] and drift

grounds for dugongs around Sungai Pulai, Johore, macroalgae (e.g. Amphiroa fragilissima] form

and their feeding trails can be seen clearly at low important components of this shoal community and

tides. The shoal is made up of calcareous sandy mud seasonally, from April to July and in November, the

substrate and supports a mixed species community seagrass bed is overgrown with them. dominated by Enhalus acoroides. Halophila ovalis The waters around Tanjung Adang Laut as well

and Halophila spinulosa. This association occupies as those of Tanjung Adang Darat and Merambong

the middle zone 11.5-1.8 ml and is exposed during shoals support the fisheries which feed the

extreme low spring tides. Cymodocea serrulata, inhabitants of coastal communities. Seventy-six

Syringodium isoetifolium and Halodule uninervis species of fishes (including the Indian anchovy inhabit the deeper, narrow edge zones (1.8-2.1 ml Stolephorus indlcus, barramundi Lates calcarifer which remain unexposed. and Spanish flag snapper Lutjanus carponotatus]

The edge zone is bare at some places, while at and others including prawn (e.g. Penaeus indicus] others isolated patches of Cymodocea rotundata, and crabs [Portunus pelagicus and Scylla serrata]

Halophila spinulosa, Halophila minor or Halodule have been reported in the area"'"'^°'. The locals also

pinifolia occur. In the deeper zone (2.1-2.7 ml used the shoal as a gleaning site for collection of sparse, isolated patches of Enhalus acoroides and gastropods such as Strombus canarium and Lambis Halophila ovalis are found. Enhalus acoroides and lambis and bivalves such as Gafranum spp. and

Halophila ovalis occur at depths of 1.5-1.8 m, and Modiolus spp.

are also exposed during low spring tides, but are

able to withstand short periods of desiccating conditions. Cymodocea serrulata and Syringodium

isoetifolium are less resistant and therefore tend to

occur in the unexposed edge zone 11.8-2.1 ml.

This seagrass bed also supports a total of 25 species of macroalgae. Rhizophytic macroalgae ;,v^?^^B such as Avrainvillea erecta, Caulerpa spp. and Udotea occidentalis are set into the sandy or sandy mud substrates whereas epiphytes such as Bryopsis plumosa. Ceramium affine. Chaetomorpha spiralis, Cladophora spatentiramea, Cladophora fascicularis, K*»^iV Cladophora fuliginosa, Dictyota dichtoma, Hypnea cervicornis. mi Gracilaria coronopifolia, Gracilaria fisherii and Gracilaria salicornia are attached ^m~M.'1 directly to seagrasses. Species such as Entero- Tanjung Adang Laut subtidal shoaliwitti mixed species morpha calthrata and Gracilaria textorii attach to seagrass community. Nine species of seagrass inhabit the

mollusk shells or polycheate tubes. Drift macro- calcareous sandy mud substrate of the shoal.

^^ Malaysia 157

and Hatophita beccani has been largely replaced by the the east coast is a common activity for landfill and

more aggressive Halodule pinifolia which now forms a shoreline stabilization projects. Dredging is being

monospecific bed. Standing biomass of Halophila carried out in the Halophila beccarii and Halodule

beccaril has been dramatically reduced from CSV-ASA pinifolia beds of Pengkalan Nangka, Paka shoal and

g dry weight/m'' Ishoot density of 2078-6 798/m'| before Telaga SImpul. This dredging will lead inevitably to the mining in 1996 to 0.58-0.59 g dry welght/m^ Ishoot Increased sedimentation and smothering of sea-

density of 758-1 386/m'l from April 1997 until January grasses. More bed removal will eventually occur If

1999. Halodule pinifolia biomass and shoot density dredging is to be continued to supply the increasing

fluctuated from 10.1 to 56.6 g dry weight/m' and 2 1A5.3 demand for sand. to 89A6/m' respectively during that period. Small-scale destructive fishing by pull net at

In Sabah, no Information on decline or loss of Pengkalan Nangka, Kelantan, and Paka shoal, seagrasses has been reported. However, symptoms of Terengganu, dislodges the seagrasses and reduces the

a declining seagrass bed were visible at Sepangar Bay. seagrass cover Harvesting of bivalves, Hiatula solida,

The middle sublittoral belt of Halodule unmervis and Meretrix meretrix and Geloina coaxans at Pengkalan Cymodocea rotundata was eroded by wave action. Edge Nangka, Kelantan, has been shown to cause plants have exposed rhizomes and roots. Sediment mechanical damage, reduce seagrass cover and retard

erosion and instability appear to be Implicated In the the spread and colonization of seagrasses. Other

progressive decline of these seagrasses In the shallow threats include the increasing public use of natural water. seagrass areas, such as for recreational boating, fish-

ing and swimming in Port Dickson. Negri Sembllan,

PRESENT COVERAGE and as avenues for transportation such as in the

Information on the total area, extent or size of seagrass narrow channels In the Paka Lagoon, Terengganu, and

beds in Malaysia Is Incomplete. The individual and total Sungai Pulal-Merambong-Tanjung Adang shoals, estimated areas presented (Table U.ll are for the Johore.

known seagrass areas In Peninsular Malaysia. This Is In Sabah, seagrass and coral reef associated

an underestimate as seagrass areas In the offshore ecosystems are areas of gleaning and collection for Islands are not Included. Although Ismail"" has food resources. Uncontrolled collection of flora such as

reported that seagrass beds In Sabah occur in patches

ranging In size from 10 m to 150 m in diameter, no further data are available, though it is known that, Table U.I

compared with Peninsular Malaysia, seagrasses are Estimate of known seagrass areas In Peninsular Malaysia

common in Sabah. An approximate estimate for

seagrass areas In Sabah would be many times that of State and location Area Ihal the known seagrass areas in Peninsular Malaysia. Kelantan

Pengkalan Nangka Lagoon 40.0 PRESENT THREATS Kampung Baru Nelayan-Kampung

The Malaysian coastal zone Is being subjected to a high Sungai Tanjung 27.0

degree of resource exploitation as well as pollution. Pantal Baru Lagoon 20.0

Seagrass beds grow in shallow, coastal zone waters Terengganu | and this renders them susceptible to unplanned and Sungai Kemaman 17.0

unmanaged urban and industrial development. These Chukai, Kemaman 3.3

problems are compounded by a lack of environmental Telaga Simpul 28.0 assessment procedures for developments and lack of Sungai Paka Lagoon U awareness about the Importance of seagrasses. In the Sungai Paka shoal 43.0

past, and even at present, losses of seagrass River bank of Sungai Paka 1.5

communities In the coastal areas of Malaysia caused Merchang 3.0

either by natural causes or human activities generally Gong Batu 5.0

pass unnoticed or unrecorded. States such as Kedah Negri Sembllan | and Malacca are undertaking land reclamation and Teluk Kemang 11.0

expansion programs. Land reclamation and expansion Jofiore

in Johore Is occurring for the development of new port Tanjung Adang Laut shoal 40.0 facilities. With more expansion planned, the future Tanjung Adang Darat shoal 42.0

intention is to completely reclaim the stretch of Merambong shoal 30.0 seagrass beds of Merambong-Tanjung Adang shoals, Total estimated area In Peninsular Malaysia 315.5 the feeding ground of dugongs. Sourcing for sand on

ferf- 158 WORLD ATLAS OF SEAGRASSES

Case Study U.3 COASTAL LAGOON SEAGRASS COMMUNITY AT PENGKALAN NANGKA, KELANTAN

The intertidal area and two shoals in the lagoon all harbor a mixed Hatodule pinifolia and Halophila

faeccar/V community. Hatodule pinifolia grows in pure and extensive subtidal meadows on soft muddy

substrates at depths of 1.6 to 2.0 m. Haloptiita

faeccan/ grows in shallower parts, at depths of 0.9 to

1.5 m in monospecific and very dense meadows on sandy substrates. The two species are able to withstand a wide fluctuation of salinity from to 18

psu. The meadow is a site for the collection of

bivalves (e.g. l-liatula solida and Geloina coaxans] and artisanal fishing. Digging for bivalves has

caused a lot of damage to the meadow (see photograph). Since 1991 the lagoon has also been

used for fish cage farming of Lates calcanfer and Epineplielus sexfasciatus. Seasonally, from June to

July, the migrant wader. Egretta garzetta, used the

shoals as a feeding ground on its migrations until Halophila beccani meadow is a harvesting site for Hialula solida

two shoals were completely destroyed by sand and Geloina coaxans. Digging has caused damage to

dredging in early 1999. the bed.

Caulerpa spp. and fauna such as sea cucumbers, particular regard to species of rare or gastropods and bivalves, and illegal fishing with endangered flora and fauna;

explosives are among the major causes of damage to Ibl allow for the natural regeneration of aquatic

coral reefs and associated seagrasses. Such activities lite in such area or part thereof where such life

not only cause loss of flora and fauna but also create an has been depleted;

imbalance within the ecosystem from which seagrass (cl promote scientific study and research in

beds are unlikely to recover quickly. respect of such area or part thereof;

Id] preserve and enhance the pristine state and POLICY RESPONSES productivity of such area or part thereof; and

In the earlier part of this chapter, it was mentioned that |e) regulate recreational and other activities in seagrass beds are the least protected of the three main such area or part thereof to avoid irreversible

marine ecosystems in Malaysia. It is strongly damage to its environment." recommended that seagrass beds, especially those around offshore islands that have been gazetted as Furthermore: marine parks (Pulau Redang; Pulau Perhentian, "(21 The limits of any area or part of an area Terengganu; Pulau Tioman. Phang; Pulau Tengah; established as a marine park or marine reserve Pulau Besar; Pulau Sibu; Pulau Tinggi. Johorel be given under subsection HI may be altered by the

protection as marine parks or reserves under the Minister by order in the Gazette and such order

Fisheries Act 1985. Under Part IX. Section Al(ll and |2l may also provide for the area or part of the area of the Fisheries Act 1985 the Minister of Agriculture to cease to be a marine park or marine reserve."

may order in the Gazette the establishment of any area

or part of an area in Malaysian fisheries waters as a The question of affording comprehensive

marine park or marine reserve in order to: protection to marine ecosystems gazetted under the

"(a| afford special protection to the aquatic flora present Fisheries Act 1985 has been the subject of

and fauna of such area or part thereof and to intense scrutiny by marine scientists, government protect, preserve and manage the natural officials and conservationists. The bone of contention

breeding grounds and habitat of aquatic life, with has been the separation of the land on islands

-7^,'^ Malaysia 159

gazetted as marine parks and reserves from the waters surrounding the islands. Under these circum- stances, while the authorities vested with the powers to manage and enforce the marine park laws can do so at sea, they have no jurisdiction whatsoever over what happens on land. This could be resolved based on practices

adopted by Sabah Parks and the present trend of promulgating state parks enactment for the protection

of ecosystems. At present, Sabah Parks has under its auspices three marine protected areas: Tunku Abdul Rahman Marine Parks, Pulau Tiga Parks and Turtle Islands Parks. All harbor seagrasses and were gazetted as state parks under the State Parks Enactment 1984. Marine areas gazetted as state parks in Sabah are afforded more comprehensive protection

under the enactment than marine parks or reserves in

Peninsular Malaysia. These parks are protected in their entirety without separating the marine and terrestrial components. Boat unable to move because of thick Enhalus acoroides bed. Several states in Peninsular Malaysia have

promulgated enactments for the gazettement of state parks. Johore has gazetted the National Parks (Johorel ACKNOWLEDGMENTS Corporation Enactment 1991. Terengganu has a Support from the United Kingdom Department for international

Terengganu State Parks Enactment. Development IDflDI is gratefully acknowledged, Can the above policies be applied for the

management of marine protected areas in Peninsular AUTHORS

Malaysia? The lies in answer encouraging concurrent Japar Sidik Bujang, Department of Biology. Faculty of Science and of gazettement marine protected areas under both Environmental Studies, Universili Putra Malaysia, 43400 UPM, Serdang, federal and state legislation using the Fisheries Act Selangor Darul Ehsan, Malaysia, Tel: +603 10189/16 6626, Fax: +603 1985 to gazette the protection of the waters 1018656 7454. E-mail: laparldfsas, upm.edu, my surrounding the islands as marine parks or reserves, and state park enactments to gazette the terrestrial Muta Harah Zakaria, Faculty of Agncultural Sciences and Food, Universili component of the marine protected areas as state Putra Malaysia Bintulu Campus, Jalan Nyabau, RO. Box 396, 97008

parks. Bintulu, Sarawak, Malaysia.

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23 Mashoor M, Yassin Z, Abdul Razak L, Ganesan M (1994). Abstract: 36 Lim LH, Hishamuddin 0, Japar Sidik B, Noro T [2001].

The Distribution of Phytobenthos along the Coastal Water of Pulau Seaweed community in degraded coral reef area at Teluk

Besar, Johore, Malaysia. Presented at The International Kemang, Port Dickson, Negeri Sembilan. In: Japar Sidik B, Arshad

Conference on Applied Ecology and Biology of Benthic Organisms. A, Tan SG, Daud SK, Jambari HA, Sugiyama S ledsl Aquatic

The Centre for Extension and Continuing Education, Universiti Resource and Environmental Studies of the Straits of Malacca: Pertanian Malaysia. Current Research and Reviews. Malacca Straits Research and

24 Anisah A, Zulfigar Y 119981. Seagrass of Pulai Sipadan, Sabah, Development Centre IMASDECI, Universiti Putra Malaysia, Serdang.

Malaysia: A preliminary survey Malayan feature Journal 5213, 41: pp 99-1 10. 223-235. 37 Lee CN [1998]. Seagrass Communities in the Coastal Waters of

25 Muta Harah Z, Japar Sidik B, Hishamuddin [19991. Flowering, Port Dickson. BSc thesis, Department of Biology, Universiti Putra

fruiting and seeding of Halophila beccan/ Aschers. Malaysia, Serdang.

IHydrocharitaceael from Malaysia. Aquatic Botany bi. 199-207. 38 Japar Sidik B, Arshad A, Hishamuddin 0, Shamsul Bahar A [1995].

26 Muta Harah Z, Japar Sidik B, Law AT, Hishamuddin (20001. Halophila decipiens Ostenfeld IHydrocharitaceael: A new record of

Seeding of Halophila teccanV Aschers. in Peninsular Malaysia. seagrass for Malaysia. Aquatic Botany 52: 151-154.

Biologia Manna Mediterranea 7121: 99-102. 39 Muta Harah Z, Japar Sidik B, Fazrullah Rizally AR, Mansoruddin A,

27 Mohd Raiuddm MK [19921. Species composition and size of fish in Sujak S [2002, in press]. Occurrence and systematic account of

seagrass communities of Peninsular Malaysia. In: Chou LM, seagrasses from Pulau Redang, Terengganu, Malaysia. In:

Wilkinson CR ledsl Third ASEAN Science and Technology Week Proceedings National Symposium on Marine Park and Islands of

Conference Proceedings, Vol. 6, Marine Science: Living Coastal Terengganu: Towards Sustainable Usage and Management of

Resources. Department of Zoology, National University of Islands, Grand Continental Hotel, Kuala Terengganu. Department

Singapore and National Science and Technology Board, Singapore, of Fisheries Malaysia, Ministry of Agriculture Malaysia, Kuala

pp 309-313. Lumpur.

-^--cp^^ The western Pacific islands 161

15 The seagrasses of THE WESTERN PACIFIC ISLANDS

R. Coles

L. McKenzie

S. Campbell M. Fortes

F. Short

western Pacific island region includes the to environmental damage. While these issues are Thecountries and island states of Micronesia, recognized and are being addressed by planning

Melanesia and Polynesia. These countries are legislation, enforcement Is difficult or impossible In

located in the tropical Pacific Ocean; almost all the many of the islands. This dilemma of land tenure may

islands are in a zone spanning the equator from the be an obstacle to the environment planning needed to

Tropic of Cancer in the north to the Tropic of Capricorn ensure a sustainable habitat for seagrass.

In the south. There are 24 species of seagrasses, including Most islands, with the exception of Papua New Ruppia'", found throughout the tropical Indo-Paclflc'^'.

Guinea and Fiji, are small by continental standards Our best estimate Is that 13 of these are found in the and are separated by expanses of deep ocean waters. western Pacific islands. These include the genera of

It Is no easy task estimating even the number of Cymodocea, Enhatus, Halodule, Halophlla, Syringo-

Islands in the western Pacific region. For example dium, Thalassia and Thalassodendron. It is possible there are in excess of 2 000 islands In Micronesia that new species remain to be described from the alone, some of which may not be permanent and can western Pacific, as collections from this region are be swamped by high tides. There are two main types relatively few. Seagrass species distribution across the of islands - the high islands such as Fiji, Papua New western Pacific is believed to be Influenced by the

Guinea and most of the Solomon Islands, and the low equatorial counter-current in the northern hemi-

Islands and coral reef atolls such as Majuro and sphere and the equatorial current in the southern

Kiribati. In the Pacific, as In the rest of the world, most hemisphere'", with the number of species declining

of the cities and towns are located in the coastal with easterly distance. The reduced bottom area

region. Only In Papua New Guinea are there large available and the effect of past changes in sea level towns located away from the coast. There has been a would also reduce species numbers along an easterly marked change away from mostly subsistence living. gradient'^'. The numbers are greatest near the biggest

As a consequence Pacific islanders are no longer land mass, with 13 species in Papua New Guinea'", and totally rural, and urban growth is outstripping total least in the easternmost islands; only one species is growth. Human populations are increasing throughout known from Tahiti'". the region and can be as high as 23 000 people per km^ Seagrasses across the region are also often

le.g. Marshall Islands!'". closely linked, with complex interactions, to mangrove

Most countries in the Pacific list human waste communities and coral reef systems. Dense seagrass

disposal as a significant issue and this is likely to communities of Enhalus and Cymodocea are often affect seagrass meadows. Only larger towns have present on the intertidal banks adjacent to mangroves sewage systems, but most of the effluent discharges and fringing reefs. Into the sea'". Along with septic systems and village latrines, the eventual nutrient loads of sewage BIOGEOGRAPHY

systems to inshore and reef platform seagrasses may Western Pacific seagrass communities grow on

be significant. Custom ownership of land (inherited fringing reefs, in protected bays and on the protected ownership of land and nearshore regions by side of barrier reefs and islands. Habitats most suited indigenous villages or families) gives the owners the to tropical seagrasses are reef platforms and lagoons

right to do as they wish with the land even if that leads with mainly fine sand or muddy sediments enclosed 162 WORLD ATLAS OF SEAGRASSES

by outer coral reefs. These habitats are influenced by only Halophila species present in Fiji is the subspecies pulses of sediment-laden, nutrient-rich freshwater, Halophila ovalis bullosa identified by den Hartog'" resulting from seasonally high summer rainfall. Thalassodendron ciliatum has been recorded

Cyclones and severe storms or wind waves also from Palau. Papua New Guinea and Vanuatu'"". It is

influence seagrass distribution to varying degrees. On unusual in being restricted almost exclusively to rocky

reef platforms and in lagoons the presence of water or reef substrates. It is often found on reef edges

pooling at low tide prevents drying out and enables exposed to wave action, protected from damage by its

seagrass to survive tropical summer temperatures. flexible woody stem and strong root system. It can be

Enhalus acoroides is the only species that difficult to locate because of its exposed reef edge habit

releases to the surface of the water when and is uncommon in records from most Pacific island

reproducing sexually. This feature restricts its countries.

distribution to intertidal and shallow subtidal areas. It Generally low nutrient availability"" is a likely

is a slow-growing, persistent species with a poor determining factor in seagrass extent on reef habitats

resistance to perturbation"", suggesting that areas across the western Pacific islands. Seagrasses

where it is found are quite stable over time. Cymodocea frequently grow more abundantly on intertidal reef

IS an intermediate genus that can survive a moderate platforms and mud flats adjacent to populated areas

level of disturbance, while Haiophlla and Hatoduie are where they can utilize the available nutrients. Seagrass

described as being ephemeral genera with rapid communities in the western Pacific islands must

turnover and high seed set. well adapted to high levels tolerate fluctuating and extreme temperatures, fluc-

of disturbance'*'. tuating salinity during rainfall seasons, and exposure to

Thalassia hemprichii is the dominant seagrass storm-driven waves and erosion. Often the sediments found throughout Micronesia and Ivlelanesia, although are unstable and their depth on the reef platforms can

It IS absent from Polynesia and Fiji. Thalassia be very shallow, restricting seagrass growth and

hemprichii is often associated with coral reefs and is distribution.

common on reef platforms where it may form dense Most tropical species in the western Pacific are

meadows. It is able to grow on hard coral substrates found in waters less than 10 m deep. There is a complex

with little sediment cover. It can also be found depth range for seagrasses as the availability of bottom

colonizing muddy substrates, particularly where water substrate and shelter for seagrass growth is controlled

pools at low tide. In the Indo-Pacific region. Thalassia by the topography of coral reef communities which often

hemprichii is commonly the climax seagrass species. protect the seagrass habitats from wave action. The

Species of Haiodule, Cymodocea and Syringodium may location of the seaward edge may be determined by the

at times also be found in dense meadows associated depth or location at which coral cover becomes consis- with reefs and on reef platforms. Enhalus acoroides tent or by the edge of a platform that drops rapidly into and Cymodocea rolundata are also widespread deeper water This distribution and the topographic

throughout the region but absent from Polynesia and features controlling it differ from many temperate

Fiji. Haiodule uninervis is abundant throughout regions where availability of light for photosynthesis

Melanesia and Polynesia, but is only found in Guam and controls the depth penetration of seagrasses.

Patau in Micronesia. Both Cymodocea serrulata and Exposure at low tide, wave action and low salinity

Cymodocea rotundata were recorded in intertidal from freshwater Inflow determine seagrass species

regions of Micronesia'" and in Papua New Guinea, survival at the shallow edge. Seagrasses survive in the eastern Micronesia and Vanuatu'"". Intertidal zone especially at sites sheltered from wave

Syringodium isoetifolium has only been recorded action or where there is entrapment of water at low

in the most westerly islands of Micronesia (e.g. Palau tide (e.g. reef platforms and tide pools! protecting the

and Yap), in Tonga and Samoa in Polynesia, in Papua seagrasses from exposure Ito excessive heat or drying)

New Guinea, and in Vanuatu and Fiji in Melanesia. In Fiji at low tide. At the deeper edge, light, wave action and Syringodium isoetifolium occurs as a widespread and the availability of suitable bottom substrate limit dominant seagrass species. distribution.

Halophila species are widespread through the The stresses and limitations to seagrasses In the

Pacific islands with the exception of the eastern tropics are generally different from those In temperate

Micronesia islands. In the western islands of the west- or subarctic regions. They include thermal Impacts

ern Pacific. Halophila ovalis is found in intertidal habitat from high water temperatures; desiccation from

mixed with larger seagrass species like Enhalus overexposure to warm air; osmotic impacts from

acoroides in Palau or Thalassia hemprichii in Yap. hypersallnlty due to evaporation or hyposallnlty from

Halophila ovalis is also commonly found in deep water wet season rain; radiation impacts from high irradlance at the offshore edge of mixed seagrass meadows. The and UV exposure. Both Halophila ovalis and Thalassia

irv S .

The western Pacific islands 163

* ' Vap Nomwin

. Pikclol Chuuk Wolcai J (Truk) Po Impel Launpik

* Salawan FEDERATED STATES OF MICRONESIA

PA CIF/C OCEAN

100 200 300400 500 Kilometers q

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^H

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i. FIJI *».

, Nukubiit.1 Reef V. . »

•* TONGA 200 400 600 800 1000 Kilometers • 160- E 170°E 180* 170'W

Maps 15.1 and 15.2

Western Pacific islands IwestI (topi and Western Pacific islands least!

hemprichii were found in intertidal regions in Yap, community interactions presented for reef flat species Micronesia'"', where tolerance to iO°C temperatures may not necessarily refer to areas with seagrass. and low salinity allow these species to colonize. Other Munro"^' lists 75 species of mollusks collected by species present in Yap, Syringodium isoetifolium and subsistence gleaners in the Solomon Islands, Papua

Cymodocea serrulata. were restricted to deeper water New Guinea and Fiji from mangroves, reefs, seagrass by these conditions. meadows and sand flats. Other mollusks such as the

Reef platform seagrass meadows support a wide trochus shell [Trochus nlloticus] found in seagrass range of mollusks, fish, holothurians and decapods. meadows are collected as a source of cash income. The available literature does not focus on the ecological Similarly the holothurians have been a valuable source role of seagrasses and information on complex of cash income, although now heavily overfished"". We 164 WORLD ATLAS OF SEAGRASSES

have found lower value species such as Holothuria atra Seagrasses are also food for the green turtle

to be still common in seagrass meadows in parts of IChetonia mydas], found throughout the Pacific island Micronesia. region, and for the dugong [Dugong dugon], found in

Pyle"^' lists at least 3 392 reef and shore fish from small numbers feeding on seagrasses In the western - the Pacific islands but It Is not possible to distinguish Islands Palau, Vanuatu and the Solomon Islands. which species are from seagrass meadows. Klumpp ef

a/."" refer to 15^ species of tropical invertebrates and HISTORICAL PERSPECTIVES

fish that feed directly on seagrasses and Coles et at.'"' The major changes In Pacific island seagrass meadows

list and classify 134 taxa of fish and 20 shrimp species have occurred mostly in the post-Second World War

found In tropical Australian seagrass meadows giving period and are related to transport Infrastructure, some Indication of the likely use of tropical Pacific tourist development and population growth. Some seagrass meadows. Islands have seagrass maps available but most do not

Case Study 15.1 Species of seagrass found were Enhatus acoroides, KOSRAE Thaiassia hemprichii and Cymodocea rotundata. Over the last three to four decades there has

The Federated States of Micronesia is made up of been considerable coastal construction activity on four states: Kosrae. Pohnpei, Chuuk and Yap. Kosrae the islands to build modern transportation facilities,

IS the easternmost state and consists of two islands: and the seagrass meadows and reef flats at those

a large mountainous Island approximately 20 km locations have been severely impacted. Two aircraft long and 12 km wide, and a smaller 70 ha island. runways and associated causeways have been

Lelu, approximately 1 km off the northeast coast of constructed on the only available flat area on the Kosrae island - the reef flat. A detailed assessment of Kosrae reef The first runway was constructed on the

environments in 1989 learned out by the US Army shallow flat between Kosrae and Lelu Islands in

Corps of Engineers. Research the late 1960s and early 1970s. Maragos"" Center! mapped approximately 3.5 km' of seagrass reported that the causeway connecting to this meadows around the islands. Seagrass meadows runway construction had adverse effects on Lelu

were restricted to reef tops. Large dense meadows Harbour The original causeway blocks the water

were mapped adjacent to Okat and Lelu Harbours. circulation and fish runs into inner Lelu Harbour.

KOSRVE KOSRVE ISLAND ISLAND

', Fish runs Iblockedl

Water currents Road causeway __ „.^. ,, ,

y- '-^^ \, SeagrassT

' /^"meadaws - ) <^ — .__^

Mangroves, - Lelu Island

'- . Reduced

/ environrnental quality \ Sewer

1.0 _j 10

Kilometers Kilometers -.

Lelu Harbour ca 1900. Lelu Harbour 1975.

^•'-A-> The western Pacific islands 165

hiave information recorded with the precision required from expanding coastal urban development may have to identify any historical change. It is likely that some Increased the blomass of seagrass on nearby reef plat- information exists in unpublished reports and forms. In general, though, there is not sufficient histor- environmental assessments for areas subject to ical written information from which to draw direct development but, where it exists, this Information Is not conclusions on historic trends. Munro""" does report readily available. that 2000-year-old mollusk shell middens in Papua Human population growth and the need to provide New Guinea have essentially the same species tourist accommodation have led to filling In some composition as present-day harvests, suggesting coastal areas to provide new land. Certainly port indirectly that the habitats, including seagrass habitats developments and small boat marinas have been and their faunal communities, are stable and any constructed In locations without talking the presence of changes occurring are either short term or the result of seagrass meadows Into account"". Nutrient Inputs localized Impacts.

leading to a decline in seagrasses and fish catches have reduced Okat reefs fish harvest to half that of

and increased pollution problems. Fill for the pre-constructlon levels.

runway expansion further reduced water circu- The unintended environmental effects of these

lation, fish yields, water quality and seagrasses in constructions are continuing with shore erosion and

the harbor restoration by revetment still occurring at Lelu In the mid-1980s, a new airport and dock were Harbour and adjacent to villages near the new

constructed in Okat Harbour on the north of Kosrae airport. While It is easy to criticize a decision to build

Island. Construction burled a large area of the infrastructure on top of coral reef platforms, it is

offshore reef flat seagrass meadows (see sketch hard to suggest a feasible land-based on maps belowl. Also, during dredging activities, the such a mountainous island. Flat areas available are

rate of slurry discharged into a retention basin either inhabited or mangrove covered. It would be

exceeded the basins capacity, causing the slurry to hoped that if these projects or similar were under- overflow and burying an adjacent 10 ha of seagrass taken today, better environment management sys-

and coral habitat under 0.25-0.5 m of fine mud. tems In place would at least reduce the unintended The construction also changed the water effects and slurry overflow that occurred. circulation, and the strong currents caused

shoreline erosion. These impacts are reported to Source: Maragos"".

.-^-

currents Reef line Stronger I J^^^^r^ X--\-'-i

Kilometers Kilometers

Okat Harbour and Reef 1978, Okat Harbour and Reef 1988. 166 WORLD ATLAS OF SEAGRASSES

AN ESTIMATE OF PRESENT COVERAGE Species lists are available for the western Pacific region'" but they are not available for many of the

individual islands. Coles and Kuo"°' list seagrass species from 26 islands (including the Hawaiian Islands and Papua New Guinea] based on published records,

examination of herbarium specimens and/or site visits by the authors. Species numbers ranged from 11 on

Vanuatu to a single species In the Marshall Islands. The

numbers In Coles and Kuo"°' are conservative in some cases because they do not include unpublished reports or records. Maps of seagrass are not readily available

or are of relatively poor quality and/or reliability. Some estimation might be possible based on the high

likelihood of almost all shallow l<2 m below mean sea

level! reef flats having at least a sparse seagrass cover,

but no numerical estimation of seagrass cover in the

western Pacific has been made to date.

Geographic Information system IGIS) initiatives in the Federated States of Micronesia by the South Pacific

Banded sea snake swimming over Syringodium isoetifoiium and Regional Environment Program should improve map

Halodule uninervis meadow, Nukubuco Reef, Fiji, coverage. Simple GIS maps are already available for Kosrae although they are based on earlier aerial AN ESTIMATE OF HISTORICAL LOSSES mapping and would not be precise enough tor detailed

In the western Pacific, local coastal developments for management purposes. Project assistance to update tourism or transport infrastructure are the major cause and validate these maps would accelerate the process

of seagrass toss. In Kosrae and other members of the of providing a publicly available set of maps for these

Federated States of Micronesia the development of local islands. Partial maps are available for other western

airports has contributed to a loss of seagrass on reef Pacific islands although their validity is uncertain and

platforms. The Kosrae airport, for instance. Is placed on likely to be variable.

landfill covering a reef platform and seagrasses"". In CSIRO (Australia's Commonwealth Scientific and

Patau, the building of causevi/ays without sufficient Industrial Research Organisation! has recently surveyed

consideration of the need for culverts to maintain water Milne Bay Province in Papua New Guinea. Seagrass was

flow has caused localized seagrass loss"". In Fiji, seen at 103 locations out of a total of 1 126. Seagrass eutrophicatlon and coastal development are the primary was found at several areas throughout the province,

causes of seagrass loss. Little Information is available mostly on shallow areas adjacent to the larger islands

on the loss of seagrass habitats In Papua New Guinea, such as the Trobnand, Woodlark and Sudest Islands. but away from major population centers losses are Cover was up to 95 percent In these areas. The

likely to be small and again associated with transport dominant species were Thalassia hemprichii. Enhalus Infrastructures. acoroides and Halophila ovatis with some Cymodocea

Maragos""details the loss of mainly coral reef flat serruiata, Halodule uninervis and Syringodium

habitat, but Including seagrasses and mangroves. In isoetifolium'^'". To the best of our knowledge no other

the Federated States of Micronesia from construction broadscate surveys have been conducted for Papua New

activities associated with plantations, transportation, Guinea outside individual published site descriptions.

military activity, urban development, aquaculture development and resort development. Coastal road USES AND THREATS construction around the Islands of Pohnpel and Kosrae Traditional uses of seagrass by communities in the

resulted in the dredging of many hectares of seagrass western Pacific Include manufacture of baskets; and mangrove habitat. burning for salt, soda or warmth; bedding; roof

Losses of seagrasses such as these are likely to thatch; upholstery and packing material; fertilizer; be widespread across the Pacific islands as there has insulation for sound and temperature; fiber

been little attention paid to protecting seagrasses. substitutes; piles to build dikes; and for cigars and

Modern mapping and monitoring techniques should in children's toys'^". Enhalus acoroides fiber is also the near future enable some baseline estimation of the reported to be used on Yap, Micronesia, in the total areas of the seagrass resources of the region. construction of nets'"'. Enhalus acoroides fruit Is w Regional map: The Pacific VII

< 03

I O 2

— (-

c ffi

uj s < (0 S;

i»J »; U o o § h- u • •--. w ^k, M O -^ ^ u. a. fP \v cS • V < (0 ^o: £q uS. ii2 •- o 1 >l

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. ^

•f xz. VIII WORLD ATLAS OF SEAGRASSES

SEAGRASSES AND PEOPLE

Recreational fisher standing in a seagrass bed. Bali. Indonesia. Food IbivalvesI collected Irom seagrass beds, Mozamoique

Beach seme is pulled over a seagrass meadow in the

Philippines to catch sardines or anchovies that pass by.

Hj: ,^^:,.-i^ dbalone from Phytlospadix Harvesting Zosters manna for

spp, ca 1914, Pacific coasi of USA transplanting, Maine, USA.

Snorkeler over a long-bladed Zostera manna bed in New Hampshire, UbA

Trap fisherman Anibal Amade in fvlontepuez bay, fvtozambique, with a marema A fisher family on Quirimba Island, Ivlozambique with the

fish trap and holding a seagrass parrotfish Leptoscarus vaigiensis. catch from in n^ a trap fishing trip the seagrass beds.

1/ The western Pacific islands 167

eaten in some Australian traditional communities and are bound to protect the marine environments under in some parts of the western Pacific. their control. There are some 13 other international Coastal development, dredging and manna conventions and treaties which could have some developments are generic threats to seagrass in the bearing on seagrass management although in reality it tropical tourist regions but areas lost are generally is hard to measure any quantifiable outcomes that small. Causeway development in Palau" without protect seagrasses whether the programs are ratified culverts to allow water flow has led to large seagrass or not. losses as water stagnates and sediment builds up. At a regional level, laws relating to impact

Coastal agriculture may add to sediment loads in assessment and town planning have an indirect ability catchments in Papua New Guinea and Fiji. Shipping to protect seagrass from loss. In Fiji the Town Planning management influences seagrass survival adjacent to Act deals with environmental impact assessments. shipping lanes and port locations.

Climate change and associated increase in storm activity, water temperature and/or sea-level rise have the potential to damage seagrasses in the region and to influence their distribution causing widespread loss.

Reef platform seagrasses are already exposed to water temperatures at low tide greater than 40°C and an in- crease in temperature may restrict the growth of the inner shallow edge of reef platform seagrass. Sea-level rise and associated increased storm activity could lead to large seagrass losses through increased water move- ment over seagrass beds and erosion of sediments. It is possible that with a rise in sea level areas that are now seagrass habitat may be colonized by coral.

SEAGRASS PROTECTION Many western Pacific island communities have complex and at times unwritten approaches to land ownership, custom rights and coastal sea rights. These are partially overlaid by arrangements put in place by Halophita ovabs. a species commonly found in the western Pacitic. colonizing powers during and after the Second World

War, leaving the nature and strength of protective Land below high water is administered by the Ministry arrangements open for debate""'. In implementing any for Land and Mineral Resources through the protective arrangements for seagrasses the challenge Department of Lands and Surveys. If a mangrove area will be to develop an approach that will suit all parties land presumably also seagrasses] is be recldimed, the and that will respect traditional ownership rights. This application is referred to the Department of Town and must also be achieved in an area where enforcement, at Country Planning for comment, recommendation and least in the sense it is used in North America and suggested conditions. It may also be referred to the

Europe, is absent or ineffective and more of a Department of Fisheries and the Native Fisheries consensus approach will be required. Commission for arbitration of compensation'". We are not able to find any legislation or In Papua New Guinea the Environmental Planning protective reserve systems that are specifically Act requires a plan for a development project to be designed to protect seagrasses. Existing reserves, submitted to the Department of Environment and however, often include seagrasses and legislation to Conservation for approval'". Palau's conservation laws protect mangroves or marine animals such as trochus are cited in the Palau National Code Annotated and are shell may indirectly protect seagrass meadows. described by the Palau Conservation Society'"' in an The South Pacific Regional Environment easy-to-understand form.

Programme Action Strategy for Nature Conservation in Two trends are emerging from the Pacific islands. the Pacific Islands region lists 232 established protected One is the recognition of the need for sanctuaries and areas and community-based conservation areas in the protected areas and the other the concept of traditional Pacific islands. Some, such as the Okat trochus sanc- or community management of these areas'"'. The role tuary in Kosrae and the Ngerul

Under the Law of the Sea Treaty, coastal nations integrated with traditional leadership and government 168 WORLD ATLAS OF SEAGRASSES

Case Study 15.2 survival. Challenges to seagrasses in the western SEAGRASSNET - A WESTERN Pacific are numerous and. similar to those in most PACIFIC PILOT STUDY parts of the world, range from human population increase, fisheries practices, pollution and onshore

SeagrassNet is a global monitoring program that development to global climate change and sea-level

investigates and documents ttie status of seagrass rise. The combination of these factors and the resources worldwide and the threats to this remoteness of many locations provide a complex set important ecosystem. Seagrasses, which grow at of circumstances that challenges our scientific

the interface of the land margin and the world's ability to monitor seagrass habitat and to test the oceans, are threatened by numerous anthropogenic diversity of habitat impacts. The western Pacific

impacts. There is a lack of information on the status region includes underdeveloped countries that have and health of seagrasses, particularly in the less extensive seagrass habitat linked to important economically developed countries. SeagrassNet's economic activities such as fishing, tourism and

efforts to monitor known seagrass areas and to map sports diving. The constraints of resources and the

and record uncharted seagrasses in the western relatively small number of seagrass scientists in the

Pacific are important first steps in understanding western Pacific have to date precluded extensive and maintaining seagrass resources worldwide. surveys and monitoring of the kind common in Synchronous and repeated global sampling of Europe and parts of the US and Australian coast.

selected environment and plant parameters is With funding assistance from the David and

critical to comprehending seagrass status and Lucile Packard Foundation, eight locations, five of trends; monitoring these ecosystems will reveal which are western Pacific islands, were identified as both human impacts and natural fluctuations in suitable. In mid-2001. long-term monitoring sites coastal environments throughout the world. were established in Kosrae, Pohnpei, Patau. SeagrassNet was developed with two com- Kavieng (Papua New Guinea! and Fiji. Scientists ponents. Research-oriented monitoring methods were identified at each location to take part in the are based on recently compiled seagrass research direct field monitoring aspect of the research. techniques for global application'^', while Quarterly monitoring is now being conducted at

community-based seagrass monitoring effort is designated sites in each country. Sites chosen were modeled after Seagrass-Watch'^^' - an Australian representative of the dominant seagrass habitat seagrass community (citizen! monitoring program existing in each location.

that IS conducted simultaneously with research- In Kosrae. a monitoring site was established in based monitoring so that comparisons of the a trochus sanctuary adjacent to Okat Harbour on the resulting data are possible. north of Kosrae Island. The site is on an intertidal An important part of the communication fringing reef horded by mangroves landward and the

strategy for SeagrassNet is an interactive system reef edge seaward. Seagrass meadows cover much

established on a website, with data entry, archiving. of the fringing reef where coral is absent. It is display and retrieval of seagrass habitat-monitoring predominately an Enhalus acoroides meadow data, ranging from plant species distribution to inshore, which changes to a meadow dominated by animal abundance and records of localized die-offs. Thatassia hemprichii and Cymodocea rotundata SeagrassNet both acquires and provides monitoring seaward. The Fisheries Development Division is

data in a format for information sharing. monitoring the site with some assistance from the Kosrae Development Review Commission A PILOT STUDY On the island of Pohnpei, the largest island Before the program can become fully established, a and location of the capital of the Federal States of

pilot study is being conducted to develop a globally Micronesia, a monitoring site was established on a applicable seagrass monitoring protocol, to relatively remote fringing reef at the southernmost compare science-based with community-based point of the mam island in an area free from physical

monitoring efforts and to test the feasibility and disturbance by human activity The site is on a reef

usefulness of this publicly available database flat where water pools at low tide, and is similar to

retrieval network. The western Pacific was chosen the site monitored on Kosrae, including the species

for the pilot because it has extensive and diverse Enhalus acoroides and Thatassia hemprichii.

seagrass habitats and a myriad of coastal issues Scientists from the College of Micronesia are

with the potential to threaten seagrass growth and monitoring the site.

Ir^ The western Pacific islands 169

In the Republic of Palau a monitoring site was Community monitoring sites were established on established on a fringing reef at the edge of the intertidal fringing reefs and local scientists, shipping channel on Koror. The nneadow extends government and non-governmental organizations are across the intertidal reef flat from the mangrove- providing support. The program is using the existing lined shore to the reef crest. Inshore, the meadow is Australian Seagrass-Watch program"^' protocols and predominately Enhatus acoroides, becoming inter- data entry systems. spersed with Thaiassia hemprichii, which increases in presence along with Halodule uninervis and

Halophiia ovalis seaward. The site is adjacent to coastal development and receives stormwater and agricultural runoff. Scientists of the Palau Inter- national Coral Reef Centre and Coral Reef Research

Foundation are monitoring this site.

In Papua New Guinea, seagrass monitoring was conducted near Kavieng in New Ireland, an island province in the northeast. With the permission of the village leader a monitoring site was estab- lished on the fringing reef flat of a small island.

Nusa Lik. The site is intertidal with a mixture of Halodule uninervis, Enhalus acoroides, Thaiassia hempnchii, Cymodocea serrulata and Halophiia ovalis. The outer edge of the seagrass was deter- mined by the edge of the coral reef. Staff attached to Thaiassia hempnchii and Cymodocea rotundata meadow on the Fisheries Research Laboratory and local fish- intertidal fnnging reef, Kosrae, Federated States of Micronesia. eries college are monitoring the site.

Fiji has environmental issues similar to the ENCOURAGING RESULTS other western Pacific island countries, such as Preliminary results from the scientific monitoring deforestation, soil erosion and sewage effluent. A indicate that the sampling protocols appear suitable, monitoring site was established on Nukubuco Reef although adjustments and refinements may occur in Laucala Bay This monitoring site is different from from time to time as the program develops. Data sites at other localities, as it is on a barrier reef. No entry via the website lwww.seagrassnet.org) was suitable fringing reef sites similar to other successful, although access to the Internet is limited participating countries could be found. The site was in some countries. Quality control and data chosen because the seagrass distribution and validation are being completed at the University of abundance of Nukubuco Reef have been mapped as New Hampshire's Jackson Estuarine Laboratory. part of a University of the South Pacific postgraduate Photographic collections are being cataloged and project and the site was easily accessible from Suva. archived by the Queensland Department of Primary

The monitoring site is adjacent to a sand cay at the Industry Marine Plant Ecology Group. Herbarium northwestern edge of the reef. It is an intertidal site samples were also verified at the University of New with a mixture of Halodule uninervis. Halodule Hampshire and sent to the International Seagrass pinifolia and Halophiia ovalis subsp. bullosa close to Herbarium at the Smithsonian Institution, the cay, becoming a monospecific Syringodium Washington, DC, USA. isoetifolium meadow seaward. The outer edge of the The initial success of the pilot study has meadow was determined by the edge of the channel. encouraged scientists and coastal resource

Scientists from the University of the South Pacific managers in Africa, South America, Asia, Europe, are monitoring the site. Australia and North America to participate. The goal

The community-based seagrass monitoring IS to expand SeagrassNet to other areas of the globe program that forms the second stage of the project and, ultimately, to establish a network of monitoring was initiated in the western Pacific islands in April sites linked through the Internet by an interactive

2002 in New Ireland, Papua New Guinea. In June and database. The ultimate aim is to preserve the

July 2002 local citizens also began monitoring sites in seagrass ecosystem by increasing scientific

Kosrae, Palau and Fiji. Community participants were knowledge and public awareness of this threatened mostly school students and local villagers. coastal resource.

'Vr/v-^ 170 WORLD ATLAS OF SEAGRASSES

agencies, suggests that conservation measures and AUTHORS

the acceptance of enforcement will continue to Rob Coles, Len McKenzie and Stuart Campbell, DPIQ,

improve. Northern Fisheries Centre, P.O. Box 5396, Cairns, Queensland 4870,

There is a growing understanding that community Australia Tel: +61 (017 4035 0111. Fax: +61 1017 4035 4664. E-mail:

types such as seagrasses are vital to the health of the rob.colesl3dpi.qld gov.au reef environment and that they are threatened by climate

change as well as direct human impacts. There is clearly f^iguel Fortes. Ivjanne Science Institute CS, University of ttie Philippines,

a need in the Pacific island nations to quantify the risks Diliman, Ouezon City 1101, Philippines.

to seagrass of present management practices and to

quantify the extent and value of seagrass protection Fred Short. Department of f^atural Resources. University of New afforded by the present reserves and legislative Hampshire, Jacl

approach. Durham, NH 03824, United States.

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marine/coastal biodiversity in the tropical Pacific. In: Maragos JE. Region: Vol 2: Population, development and conservation priorities.

Peterson MNA. Eldredge LG, Bardach JE. Takeuchi HF ledsl Marine Workshop proceedings. Pacific Science Association, East-West

and Coastal Biodiversity in the Tropical Island Pacific Region: Vol 2: Center, Honolulu, pp 127-144.

Population, development and conservation priorities- Workshop 14 Richmond RH [1999). Sea cucumbers. In; Maragos JE, Peterson

proceedings. Pacific Science Association, East-West Center, MNA. Eldredge LG, Bardach JE, Takeuchi HF [edsl Marine and Pacific Region: Vol Honolulu, pp 215-235. Coastal Biodiversity in the Tropical Island 2:

2 Short FT, Coles RG, Pergent-Martini C [2001), Global seagrass Population, development and conservation priorities. Workshop

distribution. In; Short FT. Coles RG ledsl Global Seagrass Research proceedings. Pacific Science Association, Easl-West Center, 145-156 Methods. Elsevier Science BV, Amsterdam, pp 5-30. Honolulu, pp 3 Short FT, Coles RG leds) [2001). Global Seagrass Research 15 Pyle RL[1999). Patterns of Pacific reef and shore fish biodiversity Methods. Elsevier Science BV, Amsterdam. In: Maragos JE, Peterson MNA, Eldredge LG, Bardach JE, Takeuchi Biodiversity in the Tropical Island 4 Mukai H [1 993). Biogeography of the tropical seagrasses in (he HF ledsl Marine and Coastal western Pacific Australian Journal of Marine and Freshwater Pacific Region: Vol 2: Population, development and conservation

Research a-. 1-17. priorities. Workshop proceedings. Pacific Science Association.

5 Coles RG, Lee Long WJ [1999). Seagrasses. In; Maragos JE, East-West Center, Honolulu, pp 157-176.

Peterson MNA, Eldredge LG, Bardach JE, Takeuchi HF leds) Marine 16 Klumpp DW, Howard RK, Pollard DA [1989). Trophodynamics and

and Coastal Biodiversity in the Tropical Island Pacific Region: Vol 2: nutritional ecology of seagrass communities. In: Larkum AWD,

Population, development and conservation priorities. Workshop McComb AJ, Shepherd SA ledsl Biology of Seagrasses: A treatise

proceedings. Pacific Science Association, East-West Center, on the biology of seagrasses with special reference to the Australian region. Elsevier, 394-457. Honolulu, pp 21-46. Amsterdam, pp 6 Fortes MD (1998). Indo-West Pacific affinities of Philippine 17 Coles RG, Lee Long WJ, Watson RA. Derbyshire KJ (1993). seagrasses, Botanica Marina 21: 237-242, Distribution of seagrasses, their fish and penaid prawn

7 den Hartog C [1970), The Seagrasses of the World. North Holland communities in Cairns Harbour, a tropical estuary, northern Publishing, Amsterdam, Queensland, Australia. Australian Journal of Marine and

8 Walker Dl, Dennison WC, Edgar G [1999), Status of Australian Freshwater Research U: 193-210.

seagrass research and knowledge. In; Butler A, Jernakoff P [edsl 18 Coles RG (19961. Coastal Management and Community Coastal

Seagrass in Australia: Strategic review and development of an R&D Resource Planning in the Asia Pacific Region. Final report to the

plan. CSIRO. Collingwood, Australia, pp 1-24, Churchill Fellowship Foundation. 51 pp. 9 Tsuda RT, Kamura S [1990), Comparative review on the floristics, 19 Maragos JE (19931. Impact of coastal construction on coral reefs in

phytogeography, seasonal aspects and assemblage patterns of the the US affiliated Pacific islands. Coastal Management 21 ; 235-269.

seagrass flora in Micronesia and the Ryukyu Islands, Gataxea 9; 20 Skewes. Personal communication. 77-93. 21 Fortes MD [1990), Seagrasses; A resource unknown in the ASEAN

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MNA, Eldredge LG, Bardach JE, Takeuchi HF [edsl Marine and International Center for Living Aquatic Resources Management,

Coastal Biodiversity in the Tropical Island Pacific Region: Vol V. Manila, Philippines, ICLARM Education Series No. 6. 46 pp.

Species systematics and information management priorities. 22 Falanruw MC (19921. Seagrass nets. Atoll Research Bulletin (3641:

Workshop proceedings. Pacific Science Association, East-West 1-12.

Center, Honolulu, pp 39-57. 23 Palau Conservation Society (19961. A Guide to the Conservation

11 Stapel J, Manuntun R, Hemminga MA (19971 Biomass loss and Laws and Regulations of the Republic of Palau. Palau Consen/ation

nutnent redistribution in an Indonesian Thalassia hempnchii Society, Koror 19 pp.

seagrass bed following seasonal low tide exposure during daylight. 24 Federated States of Micronesia [2001). Preliminary Report to the Marine Ecology Progress Series 148; 251-262. Conference of the Parties of the Convention on Biological Diversity

12 Bndges KW. McMillan C [19861. The distribution of seagrasses of 24 pp.

Yap, Micronesia, with relation to tide conditions. Aquatic Botany 2i: 25 McKenzie LJ, Campbell SJ. Roder CA (2001). Seagrass-Watch: 403-407. Manual for mapping & monitoring seagrass resources by

13 Munro JL [1999]. Utilization of coastal molluscan resources in the community IcitizenI volunteers. Northern Fisheries Sen/ice, Cairns,

tropical insular Pacific and its impacts on biodiversity In; Maragos Australia. 94 pp. Indonesia 171

16 The seagrasses of INDONESIA

T.E. Kuriandewa W. Kiswara M. Hutomo

S. Soemodihardjo

Although seagrasses cover at least 30 000 km" sand and coral rubble. High bioturbation by, for example, throughout the Indonesian Archipelago, from burrowing shrimps tends to decrease seagrass density

Pulau Weh in Aceh to Merauke, Papua, they have and favor the pioneer species. Seagrasses growing in only been studied in relatively small areas and terrigenous sediment are more influenced by the information is therefore rather limited. Nonetheless an turbidity, seasonality, fluctuating nutrient and salinity encouraging and increased understanding of the concentrations, and subsequent light limitation, of land importance, ecology and biology of Indonesian runoff than those in reef-derived carbonate sediments seagrasses has developed in recent years'". Vast areas with less variable seasonal dynamics. of the archipelago (e.g. the north coast of Papua, the Monospecific beds of Thalassia hemprichii are southw/est coast of Indonesia, the south and west the most widespread throughout Indonesia and occur coasts of Kalimantan] are yet to be studied, however over a large vertical range from the intertidal zone

The diversity of marine habitats in Indonesia is down to the lower subtidal zone'". Halophila ovalis also among the highest in the world and Indonesian sea- has a wide vertical range, from the intertidal zone down grass diversity is comparable to other countries in the to more than 20 m depth, and grows especially well on region. Seven genera and 12 species of seagrasses disturbed sediments such as the mounds of burrowing currently occur in Indonesian waters'""'. Two species, invertebrates. Enhalus acoroides, too, grows in a

Halophila spinuiosa and Halophila deciplens. have variety of different sediment types, from silt to coarse been recorded in just a few locations: Halophila sand, in subtidal areas or localities with heavy spinuiosa in Sorong IPapual, Lombok, East Java, Sunda bioturbation. Halodule uninervis is a pioneer species,

Strait and Riau, and Halophila decipiens in Aru, Kotania usually forming monospecific beds on the inner reef

Bay, Lembata, Sumbawa and Jakarta Bay. Two further flat or on steep sediment slopes in both the intertidal species, Halophila beccarii and Ruppia maritima, are and subtidal zones. known only through specimens at the Bogor Herbarium and have not recently been found in the field. ECOLOGY Indonesian seagrasses either form dense The majority of detritus produced by Indonesian monospecific meadows or mixed stands of up to eight seagrasses is believed to settle within the beds, with an species. Thalassia hemprichii, Enhalus acoroides, estimate of only 10 percent exported to other

Halophila ovalis, Halodule uninervis, Cymodocea serru- ecosystems'". Most of the nutrients lost by leaf lata and Thalassodendron ciliatum usually grow in fragmentation through decomposition or harvesting by monospecific beds'", and muddy substrates on the alpheid shrimps are translocated to the sediment and seaward edges of mangroves often have meadows of about 80 percent of the nitrogen content is denitrified high biomass. Mixed-species meadows occur in the there'". This retention of nutrients within the beds may lower intertidal and shallow subtidal zones, growing best explain why seagrass beds in Indonesia maintain a high in well-sheltered, sandy (not muddy), stable and low- level of productivity despite low nutrient availability. relief sediments'". These beds are typically dominated by Detailed studies of the nutrient concentrations at pioneer species such as Halophila ovalis, Cymodocea six different locations in the Spermonde Archipelago of rotundata and Halodule pinifolia. Thalassodendron South Sulawesi have indicated that there are structural ciliatum dominates the lower subtidal zone - this and functional differences between coastal beds species can grow in silt as well as in medium-to-coarse growing on the sand and mud deposited by rivers, and 172 WORLD ATLAS OF SEAGRASSES

Table 16.1

Average biomass of seagrasses Ig dry weight/m'l at various locations throughout Indonesia

Species Sunda Banten Jakarta Flores Lombok

Strait Bay Bay Sea

Enhatus acoroides 1976 353-560 250-663 155-546 393-2 479

Cymodocea rotundata 37-106 139 18-23 34-113 39-243

Cymodocea serrulata 48-104 15-35 240 45-174 111

Halodule pinifolia - 29-126 47

Halodule uninenis 10-36 6-80 64 13-516 29-128

Halophila ovalis 2-4 8 1-8 1-3 4-46

Syringodium isoetifolium 74 102-372 25-90 33-127 85-262

Thalassia hemprichii 87-193 120-257 90-278 115-322 53-263

Thalassodendron ciliatum - 231-444

Source: Kiswara'".

Table 16.2

Average density of seagrasses (shoots/m'l at various locations throughout the Indonesi an Archipelago

Species Sunda Banten Jakarta Flores Lombok

Strait Bay Bay Sea

Enhalus acoroides 160 40-80 36-96 60-146 50-90

Cymodocea rotundata 38-756 690 26-1 136 220-1 800 253-1 400

Cymodocea serrulata 48-1 120 60-190 1056 115-1600 362

Halodule pinifolia 430-2 260 7 120

Halodule unmen/is 10-335 40-1 160 604 360-5 600 80-160

Halophila ovalis 15-240 820 18-115 100-2160 400-1 855

Syringodium isoetifolium 630 124-3 920 144-536 360-3 740 1160-2 520

Thalassia hemprichii 30-315 220-464 68-560 160-1 820 200-865

Thalassodendron ciliatum 400-840 -

therefore of terrestrial origin, and those growing cover lower, factors attributed to the less severe

offshore on secjiments derived from coral reefs. environmental fluctuations of offshore beds'". Concentrations of dissolved reactive phosphate,

ammonium and nitrate-t-nitrite were low (<2 |.iM| in the Biomass

water column at all sites, often below detectable limits, The below-ground rhizome biomass of Enfialus

but considerably higher in sediment porewater"". acoroides is six to ten times larger than that of above- Porewater phosphate concentrations 13-13 nM) were ground biomass'*'. Cymodocea rotundata, Cymodocea comparable between the two sediment types, but serrulata and l-falodule uninervis have higher below-

exchangeable phosphorus contents were two to five ground biomass when growing in established mixed

times higher in carbonate sediment (18.2-23.6 mg vegetation beds than in monospecific pioneer beds'". In

phosphorus/100 g versus ^.^-10. 9 mg phosphorus/100 general, species characteristic of climax Indonesian

gl than in terrigenous sediments. Carbonate sediments seagrass meadows [Thalassia hemprichii, Enhalus

were extremely low in organic matter compared with acoroides and Thalassodendron ciliatum] invest two to

terrigenous sediments. four times more energy into below-ground biomass The more vigorous growth of coastal seagrasses growth than the colonizing species {Halodule uninervis,

is attributed to a higher level of nutrients in the Cymodocea rotundata and Cymodocea serrulata]""'. sediment than offshore. Leaf size of Enhalus acoroides Biomass values show high variability (Table 16.11 due to

is significantly larger in coastal than offshore beds'", habitat differences, species composition, plant densities biomass and shoot densities are higher and epiphyte between locations and sampling techniques""'.

^' Indonesia 173

Map U.I

Indonesia

Seagrass density also varies considerably between locations (Table 16.21. Kiswara found that thie Table 14.3 density of Haloduie uninervis depends on tfie phenotype Average shoot density of seagrass species in mixed and (normal sfioots or thin shoots). In Gerupuk Bay, monospecific seagrass meadows in the Flores Sea southern Lombok, Haloduie uninervis densities ranged from 870 normal shoots/m' to 6 560 thin shoots/m' Species Mixed seagrass Monospecific seagrass within the same seagrass bed'". Nienhuis reported that meadow (number meadow (number Haloduie uninervis had the highest density of all of shoots/m'^l of shoots/m^) seagrass species in mixed as well as in monospecific Cymodocea rotundata 32i (2761 seagrass beds (Table 16.31. In seagrass beds where Cymodocea serrvlala 696 (767) 533 (543) foliage covers more than 70 percent of substrate, the Enhalus acoroides 54 (861 136 1581 density of seagrasses frequently depends on the Haloduie uninen/i5 2847(56891 14762(6 0761 species composition of the community and the relative Halophila ovalis 69(1171 age of the seagrasses. In some species, such as Syringodium isoetilolium 2504 (1 7361

Thalassia hemprichii, biomass is frequently a function Thalassia hempnchii 754 (748) 1459(811) of shoot density and total leaf area per leaf cluster"". Jhalassodendron cilialum 692 (2721 Seasonal studies of seagrass biomass and shoot densities in Indonesian waters are scarce but Note: In all sampling locations foliage cover i5>70 percent,

percent in significant seasonal fluctuations are known to occur"". except for Jhalassodendron ciliatum (>50 1 (SO

parenthesesl. Productivity Growth studies have been carried out in Indonesia using several techniques Using the oxygen Sea vary between 60 mg carbon/mVday and 1 060 mg evolution (photosynthesis) technique, Lindeboom and carbon/mVday which, assuming the same rates of Sandee"'' demonstrated that gross primary production production throughout the year as during the study

rates of various seagrass communities in the Flores period (October), translates to a maximum annual net Sea vary from 1230 mg carbon/mVday to 4700 mg primary production of about 387 g carbon/ml Epiphyte carbon/mVday. Seagrass respiration consumption production alone accounted for a maximum annual net rates were between 860 mg carbon/mVday and 3 900 primary production of about 8A mg carbon/m' of leaf mg carbon/mVday. They concluded that net primary surface area'"', or 36 percent of the net primary production rates of seagrass communities in the Flores production rate of the seagrass communities studied.

AS^i 174 WORLD ATLAS OF SEAGRASSES

A comparative study of two different seagrass Archipelago"". Production rates obtained from these

environments in tfie Spermonde Arcfiipelago obtained studies are summarized in Table ]b.A. very similar results using tfie same tectiniques'"'^ Erftemeijer'" demonstrated that, while there was Gross primary production rates ranged from VOO mg no difference in primary production rates of coastal and carbon/mVday to 4^00 mg carbon/m7day. offshore seagrass beds in Sulawesi, the leaf growth Interestingly, the bell-jar technique used in the rate 13.1 mm/dayl of Enhalus acoroides was Spermonde Archipelago did not reveal any significant significantly higher in muddy coastal habitats than in results difference in seagrass production rates between offshore reef habitats (1.6 mm/dayl. Similar coastal and reef environments. Net primary were obtained for Thalassia hemprichii. production was slightly negative in a number of stations and was generally below 500 mg ASSOCIATED BIOTA carbon/m/day. Low net primary rates were attributed Seagrass-associated flora and fauna remain one of the

to high community oxygen consumption rates. Higher most open and exciting fields of research for Indonesian net primary production rates were obtained from scientists. Recent studies have focused on establishing monospecific stands of Thatassia hemprlchii, where species lists and measuring abundance and biomass of combined seagrass and epiphyte net production rates various seagrass-associated taxa. With a few "' reached 1.5 mg carbon/mVday to 1.9 mg exceptions'" the majority of seagrass-associated carbon/mVday, equivalent to a maximum of 69A mg faunal studies have dealt with infauna, macrofauna, carbon/mVyear motile epifauna and epibenthic fauna (Table 16.5). Nienhuis has suggested that Indonesian seagrass communities are self-sustaining systems and export Algae have very little of their photosynthetically fixed carbon to Fishermen at Benoa, Bali and West Lombok adjacent ecosystems such as coral reefs'". The results recorded seven economically important species of obtained from the Flores Sea and Spermonde seaweeds growing in the mixed seagrass meadow of

Archipelago seem to support this general hypothesis. Cymodocea serrutata, Halodute uninervis, Thalassia Erftemeijer points out that many seagrass communities hemprichii and Thalassodendron ciUatum"'\ In South

(58 percent of his study sites) seem to use more energy Sulawesi 117 species of macroalgae are associated of than is actually produced by the autotrophic seagrass with seagrasses, composed of 50 species community This suggests that, while recycling of nutri- Chlorophyta, 17 species of Phaeophyta and 50 species exclusively ents and organic carbon is high, seagrass beds may not of Rhodophyta. Thirteen species were be self-sustaining. Filter and suspension-feeding associated with seagrass vegetation"'. macroinvertebrates constitute a significant consumer

component of the Indonesian seagrass community Meiofauna Marking methods have been used to measure leaf The meiofauna associated with monospecific Enhalus

production"" in seagrass meadows at Taka Bone Rate acoroides seagrass beds on the south coast of Lombok Atoir, Kepulauan Seribu'"'", Banten Bay"" and, most consisted of nematodes, foraminiferans, cumaceans,

recently, in Lombok"" and the Spermonde copepods. ostracods, turbelarians and polychaetes'^"'.

Table U.i

Average growth rates Imm/dayl of seagrass leaves using leaf-marking tecfiniques

Species West Java Spermonde Lombok Flores Sea Archipelago Sea

Cymodocea rotundala - - 5.5(6.81 - - Cymodocea serrulata 5.0(0.61

Enhalus acoroides 7.3 13.61 2.4(2.3*1 6.5(1.51 - - Synngodium isoetifolium 4.1 16.81

Thalassia hemprichii 4.9(1.51 1.6(3.51 3.8(8.11

Thalassodendron ciliatum 2.7 (4.71

Notes:

Production rales in parentfieses (g dry weight/m'/dayl.

* In mg ash-free dry weight/m'/day m Indonesia 175

Table U.5

Indonesian se agrass-associated flora and fauna number of species

Taxon Banten Bay Jakarta Bay Lombok Ambon Bay Kotania Bay South Sulawesi

Algae 37 34 117

Meiofauna 6 groups

MoUusks 15 55 143 (hermit crabsl

Crustaceans 25 32 84 30

Echmoderms 3 45 10

Fishes 180 78 85 168 205

Fish larvae 53

Source: Various sources'^''"'.

many of wfiich were actively emergent. A higti apparently collected from coral rubble areas adjacent abundance of nematodes was indicative of nutrient to the seagrass meadows. One hipollitid shrimp there, enrichment. Benthic foraminifera are an important Tozeuma spp., has special morphological adaptations component of Indonesian seagrass communities, but to live specifically in seagrass meadows. Its lancelet have received only rudimentary attention"". In the body shape and coloration, green mottled with small Kepulauan Seribu patch reef complex, seagrass beds white spots, provides almost perfect camouflage when are abundant and frequently dominated by associations it adheres to seagrass leaves. Hany stomatopods are of Enhalus acoroides and Thalassia hemprichiP". found in Indonesian seagrass beds with Pseudosquilla

Benthic foraminifera in this location are dominated by ciliata, an obligate seagrass-associated species'^"'. the suborders Miliolina and Rotaliina"". The most Other stomatopods, such as Odontodactylus scyllarus, abundant rotaliinids were Ammonia beccarii, Ammonia leave the reefs to forage for mollusks in adjacent umbonata, Calcarina calcar, Elpldlum advenum, seagrass beds'^^'. Rahayu collected 30 species of hermit Elpidium crispum, Elpidium craticulatum and Rosalina crabs from Kotania Bay seagrass bed. Three were bradyi. The genus Ammonia is a euryhaline group, species of Diogenes, one was a species of Pagurus and common in shallow-water tropical environments, and four were undescribed species. It is believed that

Calcarina calcar is indicative of coral reef habitats. The crustaceans in the seagrass beds of Kotania Bay are abundance of Elpidium spp. is interesting, since this much more diverse than those of other locations. euryhaline, shallow-water species is extremely tolerant of low salinities and can be found far up estuaries. The Mollusks miliolinids are represented by Adolesina semistnata, The mollusks are one of the best-known groups of Milionella sublineata, Quinqueloculina granulocostata, seagrass-associated macroinvertebrates and perhaps

Quinqueloculma parkery. Quinqueloculina sp., the most overexploited. I^udjiono et al. recorded 11 Spiroloculina communis, SpiroUna cilindrica and gastropods and four bivalves from the seagrass

Triloculina tncarinata. Both Quinquiloculina and meadows in Banten Bay'^", This rather impoverished

TrilocuUna are characteristic of shallow tropical waters. mollusk fauna was collected from monospecific Enhalus

acoroides beds, in mixed beds of Enhalus acoroides, Crustaceans Cymodocea serrulata and Syringodium isoetifolium, and

Crustaceans are a key component of seagrass food mixed beds of Enhalus acoroides, Cymodocea rotundata, webs. Recent analyses from the south coast of Cymodocea serrulata, l-lalodule uninervis, Halophila Lombok"*' demonstrated that crustaceans are the ovalis, Syringodium isoetifolium and Thalassia dominant food source for seagrass-associated fish. hemprichii. The entire bay is heavily exploited and only

Aswandy and Hutomo'^" recorded 28 species of two gastropods were common to all locations, Pyrene crustaceans in Banten Bay seagrass beds. The versicolor and Cerithium tenellum. Just four juvenile (3- tanaidacean Apseudes chill

Grenyang Bay'"'. Moosa and Aswandy'™ recorded 70 economically valuable. Gastropod families included crustacean species from seagrass meadows in Kuta Bullidae. , Castellariidae, Cypraeidae, Olividae, and Gerupuk Bays but many specimens were Pyrenidae, , Trochidae and Volutidae; 176 WORLD ATLAS OF SEAGRASSES

bivalve families were Arcidae, Cardiidae, Glycymeri- Island, Moluccas, where seagrass meadows formerly dae. Isognomonidae, Lucinidae, Mesodesnatidae, supported a high abundance of economically important

Mytilidae, Pinnidae, Pteridae, Tellinidae and . holothuroids. In 1V83, the extensive seagrass meadows

Pyrene versicolor, Strombus labiatus, Strombus in Kotania Bay supported high population densities (i.e. luhuanus and Cymbiola verspertilio were the nnost 1-2 individuals/m'l of nine economically important sea abundant gastropod species and Anadara scapha, cucumber species, namely Boinadschia marmorata, Trachycardium flavum, Trachycardium subrugosum, , l-loiothuria IMetriaiytal scabra,

Peryglypta crispata, Mactra spp. and Pinna bicolorwere l-lolotliuria nobitis, i-loiothuria vagabunda, Holothuria the most common bivalve species"". A number of Conus impatiens, l-iotothuria edulis, Thelenota ananas and

species were found. miliaris. In a 1993 Inventory of the same A high diversity of mollusks, 1^2 species from ^3 area, only three sea cucumbers were recorded within a

families, has also been reported from seagrass beds in distance of 500 m. The average body size of sea cucum-

Kotania Bay''". bers decreased from around 22 cm in 1983 to less than

15 cm in 1993. The decline of the stock and size are Echinodernris attributed to Intensive collections by local people to

The most significant echinoderm species is a sea star, supply the lucrative teripang {beche de mer] trade. Protoreaster nodosus, which feeds on seagrass Another heavily overexploited echinoderm species

detritus and the surface of broken seagrass leaves. whose population has declined sharply during the past

Forty-five species of Echinodea, Holothuridae, Ophiur- ten years is the edible sea urchin Tripneustes gratilla.

oidae and Crinoidae have been recorded in the

seagrass beds of Kuta and Gerupuk Bays. Several Fish

economically important species of Holottiuria and In 1977 one of the first studies of seagrass-associated

Actinopyga, and the sea urchin Tripneustes gratilla, fish In Indonesia collected 78 species from Thalassia

have declined in abundance'^"'. hemprichii and Enhalus acoroides meadows amongst

Similar depletions in echinoderm populations lagoonal patch reefs in Pari Island, in the Kepulauan have been reported from Kotania Bay on west Ceram Seribu complex"". Only six (Apogonldae, Atherinidae,

Case Study 16.1 uninervis, Halophila ovalis, Halophila minor. BANTEN BAY, WEST JAVA Syringodium isoetifolium and Thalassia hemprichii. Beds between 25 and 300 m in length'"' are Banten Bay covers 120 km^ and harbors several continuous along the coast of Banten Bay, from the

coral islands. The biggest inhabited island is Pulau beach to the reef edge. Panjang; the other islands are small and uninhabi- They are nursery grounds tor 165 species of

ted. The rivers Domas, Soge, Kemayung, Banten, fish'^" which feed either directly on algae and Pelabuhan, Wadas, Baros and Ciujung discharge seagrass or on seagrass-associated inverte-

into the bay Seagrass is found along the mainland brates'"', including six juveniles of grouper

Java coast in the western part of the bay, on the reef [Epinephelus bleekeri, Epinephelus fuscoguttatus,

flat of the coral Islands IPulau Panjang, Pulau Epinephelus merra. Epinephelus septemfasciatus,

Tarahan, Pulau Lima, Pulau Kambing and Pulau Epinephelus coioides and Plectropomus spp.'"').

Pamujan Besar) and on submerged coral reefs in Dugongs also occur here"". The cultivation of

the intertidal area down to a depth of 6 m. The total seaweeds in Banten Bay has Increased enormously

area of seagrass beds at Banten Bay is about 330 ha, in recent years along the coastline of all the islands,

consisting of 168 ha on the mainland and 162 ha on on the coral reef and lately also outside the reef flat the coral islands. area. Approximately 35 ha, including 25 ha or 10

The depth of the bay is not more than 10 m. Its percent of the reef flat area and 10 ha outside the

sediment consists of mud and sand'"' '*', and the coral reef flat, are now used for the cultivation of salinity varies between 28.23 and 35.34 psu™. The seaweeds and have been cleared of seagrass'"'.

rainy season is from November to March. Mangrove Transplantation studies using Enhalus acoroides

is found at Grenyang in the eastern part of the bay up were conducted in Banten Bay in 1998"". Only

to Tanjung Pontang in the west part, and In the rhizomes transplanted to muddy substrate survived

southern part of Pulau Panjang. Eight species of more than five months - these new seagrass beds seagrasses occur here: Cymodocea rotundata, are now used by local fishermen to collect fishes Cymodocea serrulata. Enhalus acoroides, Halodule and prawns"" Indonesia 177

Labridae, Gerridae, SIganidae and Monacanthidael of grounds for many economically valuable fish species. the families recorded, however, could be considered as Beds with higher densities of seagrass supported important seagrass residents. The Pari Island study higher abundance of fish, and Enhalus acoroides was followed in 1985 by a long-term study of seagrass meadows supported higher fish abundance than fish assemblages in Banten Bay, southwest . Thaiassia hemprichii.

The results from the Banten Bay study'"' supported Studies on seagrass fish in Indonesia have been earlier views that only small numbers of fish species gradually increasing since the late 1980s'^"°"'. permanently reside in seagrass beds. However, it was Indonesian seagrass fish communities are commonly also reconfirmed that seagrass beds act as nursery dominated by Siganidae [rabbitfishesi, such as Siganus

Case Study 16.2 Large amounts of seagrass detritus wash up KUTA AND GERUPUK BAYS. LOMBOK and accumulate on the beach during the strong winds of the east monsoon. Interestingly Thalasso-

Kuta and Gerupuk Bays are covered by gravel, small dendron ciliatum at Kuta Bay is able to grow on

pebbles, fine sand and mud in the river mouth, volcanic stone. During low tide the local community

where Enhalus acoroides grows. The tidal range in collects milkfish, sea cucumbers, octopus, shellfish,

the bays is about 2 m, tidal velocity and direction are sea urchins and seaweeds [Caulerpa spp., Gracilaria 2.8-10.8 cm/mm and 315°-350° at high tide and -1.5- spp. and Hypnea cervicornis] from the seagrass

10.0 cm/mm and 270°-310° at low tide. During the beds. The commercial alga, Kappaphycum alvarezi,

wet season, December to April, salinity varies from IS cultivated here. 28 to 29 psu and surface water temperature from 18

to 2^°C. In the dry season, May to November, these Associated flora and fauna of the seagrass bed of Lombok measurements are approximately 3A psu and 27°C

The most diverse seagrass beds in Indonesia Taxon group Number of species

occur here, with 11 of the 12 species present in Algae 37

Gerupuk [Cymodocea rotundata. Cymodocea serru- Meiofauna""' 6 (higher taxal

lata, Enhalus acoroides, Halodule pinifolia. Halodule Mollusk"" 55

uninervis, Halophila minor, Halophila ovalis, Echinoderm™ 45

Halophiia spinulosa, Synngodium isoetifolium, Crustacean""' 71

Thalassia hemprichii, Thalassodendron ciliatum]. Fisti'™ 85

IHalophila spinulosa is absent from Kuta. Enhalus Fisti larvae 53 acoroides and Thalassodendron ciliatum form

monospecific beds in both bays, and Halophila Source: Various sources - see references by groups.

spinulosa in Gerupuk Bay. tvlixed beds of Cymodocea rotundata, Cymodocea serrulata. Halodule pinifolia. Only four of the fish found here -

Halodule uninervis. Halophila minor, Halophila Syngnathoides biaculeatus. Novaculichthys spp.,

ovalis, Syringodium isoetifolium and Thalassia Pervagor spp. and Centrogenys valgiensis - are typi- hemprichii occur at both locations. cal seagrass fishes. Halichoeres argus and Cheilio

enermis are abundant not only in seagrass but also

Coverage area of habitat types at Kuta and Gerupul< Bays in algal beds. The dominance of Syngnathoides

biaculeatus and Cheilio enermis is unusual because,

Coverage area Ihal more commonly, the fish populations of Indonesian Kuta Bay Gerupuk Bay seagrass beds are characterized by abundant

Entialus acoroides 7.68 rabbitfish, especially Siganus canaliculatus.

Thalassodendron ciliatum 10.50 id The mam threat to the seagrass of Kuta and

Halophila spinulosa 11.07 Gerupuk Bays is the intensive collecting of intertidal

Habitat types organisms during low tide, often involving digging

Mixed vegetation 96.37 76.86 with sharp iron sticks which disturb the substrate,

Sandy bar 12.03 42.97 cut the leaves of seagrasses and uproot their

Lagoon 55.19 rhizomes. Future threats may include hotel

Dead coral 70.97 27.36 construction and operation as the area has been

Live coral 38.08 earmarked for development by the local

Volcanic stone 2.93 government. m 178 WORLD ATLAS OF SEAGRASSES

Case Study 16.3 monospecific beds of Enhalus acoroides. Mixtures KOTANIA BAY of mud, sand and coral rubble are usually covered by Thalassia hempnchii. The highest density of

Kotania Bay. Ceram Island, contains five small seagrass is found in the area between Osi and islands: Buntal. Burung, Marsegu, Tatumbu and Osi. Burung. The eastern part of the bay, called Wai Tosu,

Only Osi has freshwater and is inhabited, along with has two kinds of substrates. The sediment at the

two villages at Pelita Jaya and Kotania on Ceram mouth of a small creek is deep and muddy, and is

Island. The water around Pelita Jaya (^0 ml is covered only by Enhalus acoroides 110-20 percent

deeper than that at Kotania village (20 ml. The coverage! while there is a thin layer of mud, sand

intertidal area in the northern part of Kotania Bay is and coral rubble about 100 m in front of the

very narrow |4 to 10 ml but wider in the east and mangroves. Underneath this thin substrate is a hard

south (50 to 250 m). Seagrasses are found along the layer of coral rock. Thalassia hemprichii, Cymod-

whole coast area of the bay, except in the north. On ocea rotundata, Halodule uninervis, Halophila ovalis

Buntal and Osi Islands the sediment trapped by and Enhalus acoroides grow sporadically here to

these seagrass beds has, over time, created "cliffs" less than 35 percent coverage. Local people have set which have served as substrate for the development a fish trap around the seagrass area and built a

and seaward expansion of mangrove communities. large cage to rear sea cucumbers.

The seagrass beds have been mapped using In the southern part of Kotania Bay the

remote-sensing techniques which estimated a total intertidal zone is very flat and almost all is exposed

area of 11.2 km^ The pattern of seagrass during the lowest tides. The substrate near to the

distribution depends on the type of substrate. mangrove area is mixed mud and sand dominated by

Muddy substrate is mostly dominated by Thalassia hemprichii and Enhalus acoroides. Along

Table 16.6

Present coverage of seagrasses in Indonesia

Coverage Ihal 2 00-300 50-150 <2 5-150 2-5 0,5-18 336 20-80 30 1 73 36

Cover l%l 20-80 15-80 12-25 10-15 5-15 5-15 25-i5 30-70 15-50 5-10 30-70 20-50

Recorded species jnumberl 9 8 5 7 8 9 8 10 5 9 10 11

Hydrocharitaceae

Entialus acoroides C A R R R C VA R R VA VA

Haloptiila deapiens - - R - - - -

Halophila minor VR - - R R - - R R

Halopliila ovalis R R R VR C R R R R R R R

Haloptiila spinulosa - - - - - R

Tlialassia hempncfm C VA C R R R VA VA R R VA VA Cymodoceaceae

Cymodocea rotundata R C R VR R R R R R R R R

Cymodocea serrulata R R - - VR VR VR R - R R R

Halodule pinifolia R R - VR R R - R - R R R

Halodule uninervis R R - - R R R R R R R R

Synngodium isoetifolium R C VR VR R R R R - R R R

Ttialassodendron ciliatum C - - - C - A - R C R

Notes: C common; A abundant; R rare; VA very abundant; VR very rare. Indonesia 179

Distribution of seagrass in Kotania Bay

Species of seagrass % cover Substrate type Depth (ml PJ TL 01 BRI BTI Tl Ml

Cymodocea rotundata 10-40 Sand tO.2-2.0 / / / / / / /

Cymodocea serrulata <5 Sand 0.5-2.0 / / /

Enhalus acoroides 20-60 Mud, sand 0.5-2.5 / / / / / /

Halodule pimtolia <5 Sand +0.2-1.5 / / / / / / /

Halodule uninervis <5 Sand 0.5-2.0 / / / / / / /

Habphila decipiens 40-100 Coral rubble / /

Halophila ovalis <5 Sand +0.2-1.5 J / / / / / / Habphila minor /

Syringodium isoetifolium <5 Mud, sand 0.5-2.0 / / / /

Thalassia hemprichii <5 Mud, sand +0.2-2.5 / / / • / /

Notes: PJ Pelila Jaya; TL Tanjung Lalansoi 01 Osi Island. BF 1 Burung Island; BTI Buntat Island, Tl Tatumbu Island, Ml Marsegu Island.

the southiern part of tfie bay up to Tanjung Lalansoi lata, Halodule pinifolia. Halodule uninervis, Halophila the substrate in the deeper areas is a mixture of sand ovalis and Enhalus acoroides The sea grass density

coral rubble. IS quite high varies seasonally. and The most common seag passes and Percent coverage |

Thalassia hempnchii. Cymodocea from 40 to with h ighest there are rotun- ranges 70 percent the values | data, Syringodium isoetifolium. Cymodocea serru- always close to the mangrove areas.

Coverage (hal 10-50 0.3-1 4-5 212 25-75 1 10-1000 5-50 10-1 00 25-75 100-1000 5-50 10-100

Cover l%l 30-60 5-20 15-30 30-80 30-60 50-99 30-70 -50 30-60 50-99 30-70 30-50

Recorded species Inumberj 9 7 8 10 8 8 8 8 8 8 8

Hydrocharitaceae

fntelus acoroides VA R R A VA A VA VA VA A VA VA

Halophila decipiens - - R ~ ~

Halophila minor R VR : R

Halophila ovalis R R R R R R R R R R R

Halophila spinulosa ------

Thalassia hemprichii VA C R VA VA R VA VA VA R VA VA Cymodoceaceae

Cymodocea rotundata R C R R R R R R

Cymodocea serrulata R - R R R R R R

Halodule pinifolia R VR VR R VR R R R

Halodule uninen/is R R R R R R R R

Syringodium isoetifolium R - R R R R R R

Thalassodendron ciliatum

Notes: C common; A abundant; R rare; VA very abundant. VR very rare. 180 WORLD ATLAS OF SEAGRASSES

canaliculatus In Jakarta Bay'^", except In Lombok (see location. The development of Jakarta has destroyed the

Case Study 16.21. Indonesian seagrass fish have been mangrove swamp in Ancol, the only place that Ruppia

classified into four principal species assemblages: mantima had been reported, and this is thought to have

1 permanent residents which spend most of their caused the disappearance of this species from

lives in seagrass beds (e.g. the chequered Indonesia.

cardlnalflsh. Apogon margaritophorus]; For 1 5 years the Ancol Oceanorium in Jakarta kept

2 residents which live in seagrass throughout their two male dugongs In captivity, feeding them with

life cycle but which spawn outside the seagrass seagrasses [Syringodium isoetifolium and Halodule

beds (e.g. Hatichoeres argus, Atherinomorus uninervis] harvested from Banten Bay Unfortunately

duodecimalis, Cheilodipterus quinquelineatus, they died In November 1991"™. There is one female

Genres macrosoma, Stephanoiepis hispidus, dugong In Surabaya Zoo, which has been In captivity

Acreichlhys hajam, Hemiglyphidodon plagio- since 1985. Its food Is harvested from Celengan-

metopon, Syngnathoides biaculeatus], Muncar, East Java, about 340 km from Surabaya. It

3 temporary residents which occur in seagrass feeds mostly on Syringodium isoetifolium, which forms

beds only during their juvenile stage (e.g. Siganus 95 percent of the dugongs dietary Intake. The con-

canaliculatus, Siganus virgatus, Siganus punc- sumption rate of the captive dugong Is approximately 30

tatus, Lethrinus spp., Scarus spp., Abudefduf kg wet weight/day"". Recently Sea World of Indonesia In spp., Monacanthus cliinensis. Mulloidiclitliys Ancol-Jakarta has acquired two male dugongs. One of

flavolineatus. Relates quadnlineatus, Upeneus them was caught in seine nets In Banten Bay In 1998

tragula]; and the other one was trapped in a sero (fish trap) on

U occasional residents or transients that visit the seagrass bed at MIskam Bay In 2001.

seagrass beds to seek shelter or food. The degradation of seagrass beds In Indonesian waters has been poorly documented from only limited

areas. The decline of seagrass beds at Banten Bay was caused by converting agricultural areas and fish ponds Into an Industrial estate, with a total loss of about 116

ha or 26 percent of seagrass mainly in the western part

of the bay'"'. The decline of other seagrass beds has

been caused by reclamation activities. Less damaging

than the reclamation was the uprooting of seagrasses

by fishing boats using seine nets to catch shrimp and

fish'"'. In Kuta and Gerupuk the decline of seagrass was caused by people collecting dead coral for building

material In the seagrass beds.

PRESENT COVERAGE

It Is difficult to present accurate Information about the present coverage of Indonesian seagrass, since

Measuring tfie primary productivity of seagrass meadows in observations on seagrass ecosystems in Indonesia vary

Sulawesi using enclosures equipped wilfi oxygen electrodes. considerably in duration, location, method of sampling

and object of study, and many places In Indonesia have The first study on seagrass fish larvae and not been studied yet. Table 16.6 summarizes existing

juveniles took place In Kuta Bay and recorded 53 knowledge about the present coverage In Indonesia.

species belonging mainly to four families: Channldae, Based on this available Information, and to the best of

Ambassidae. Engraulidae and . High numbers our knowledge, we estimate that seagrass covers at

of species and Individuals were found In unvegetated least 30000 km^ throughout the Indonesian

areas full of broken seagrass leaves, and In the Entialus Archipelago.

acoroides beds. Seagrasses In Indonesia are presently threatened mainly by physical degradation such as mangrove HISTORICAL PERSPECTIVE cutting and coral reef damage, and by marine pollution Herbarium collections of seagrasses from Indonesian from both land- and marine-based sources, and by

waters were made by Zollenger in 1847 and overexploltation of living marine resources such as fish, Kostermans In 1962 and include both Ruppia maritima mollusks and sea cucumbers. The alarming amount of

from Ancol-Jakarta Bay and Pasir Putlh, East Java, and land reclamation is an increasing cause of seagrass

one specimen of Halophila beccarii from an unknown habitat loss In Indonesia. M Indonesia 181

POLICY

No specific regulation relating to seagrass is currently

available and so management is implemented through

general regulations pertaining to marine affairs,

environmental protection and management of living

resources. Of primary importance is the Act of the Republic of Indonesia (Rl) No. 5 1990, concerning the conservation of living resources and their ecosystems,

together with Act of the Rl No. 5 1994 on the ratification

of the Convention on Biodiversity and Act of the Rl No.

23 1997 concerning the management of the living environment. Apart from acts and statutes, there are three other types of regulation which are hierarchically lower than the former: they are government regulation, presidential decree and ministerial decree. To have a proper management system for coastal ecosystems, appropriate laws and regulations must be established. The Indonesian Seagrass Com- mittee (ISC) has therefore prepared a draft Seagrass Policy, Strategy and Action Plan to guide the manage-

ment of the seagrass ecosystem in Indonesia. It forms Enhalus acoroides growing among living coral in Komodo National

an integral part of the activities of the South China Sea Park. Indonesia. Project, financed by UNEP-GEF (the United Nations Environment Programme section of the Global AUTHORS

Environment Facility], and seeks to address the main T.E. Kuriandewa, W. Kiswara, M. Hutomo, S. Soemodihard|0, Research

issues concerning the management of seagrasses. Centre for Oceanography - Indonesian Institute of Sciences (LIPII,

The draft, scheduled to be completed in is Jalan 2004, Pasir Putih 1 , Ancoi Timur, Jakarta Utara 1 21 90, Indonesia. Tel: +62

expected to become a reference document in the (0121 68 3850. Fax: +62 (0121 68 1948. E-mail: indo-

formulation of official regulations by the government. seagrassOcentnn.net.id

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pada padang lamun di pantai Lombok Selatan. In: Kiswara WK, Species Composition, Abundance and Distribution of Fishes in the

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Lamun di Pantai selatan Lombok dan Kondisi Lingkungannya. Connection Workshop, 26-30 August 1991, Ipoh-Perak, Malaysia. Lembaga llmu Pengetahuan Indonesia, Jakarta, pp 64-70. 45 Sugama K, Eda H [1986], Feasibility Survey on Collection of Natural

28 Azis A, Soegiarto H [1994]. Fauna ekhninodermata padang lamun di Seeds of some Promising Fish for Floating Net-Cage Culture in

pantai Lombok Selatan. In: Kiswara WK, Moosa MK, Hutomo M Banten Bay. Scientific Report.

ledsl Struktur Komunitas Biologi Padang Lamun di Pantai selatan 46 Hendrokusumo S, Sumitro S, Tas' an [19791. The distribution of the

Lombok dan Kondisi Lingkungannya. Lembaga llmu Pengetahuan dugong in Indonesian waters. In: Marsh H led] The Dugong.

Indonesia, Jakarta, pp 52-63. Proceedings of a Seminar/Workshop held at James Cook 29 Hutomo M, Panno [1994]. Fauna ikan padang lamun di Lombok University 8-13 May 1979, North Queensland Australia, pp 5-10.

Selatan. In: Kiswara WK, Moosa MK, Hutomo M ledsl Struktur 47 Douven WJAM 11999], Human Pressure on Manne Ecosystems in

Komunitas Biologi Padang Lamun di Pantai selatan Lombok dan the Teluk Banten Coastal Zone: Recent Situation and Future Kondisi Lingkungannya. Lembaga llmu Pengetahuan Indonesia, Prospects. Teluk Banten Research Program. Report Senes No. 3.

Jakarta, pp 96-110. IHE-Oelft, WOTRO. communication. 30 Moosa MK, Aswandy I [1994]. Krustasea dari padang lamun di 48 Zainudin [20021. Personal

pantai Selatan Lombok dan kondisi lingkunggannya. In: Kiswara

WK, Moosa MK, Hutomo M ledsl Struktur Komunitas Biologi

Padang Lamun di Pantai selatan Lombok dan Kondisi Lingkungannya. Lembaga llmu Pengetahuan Indonesia, Jakarta,

pp 42-51. .

Regional map: Asia IX

85° 100° 115° 130° 145° N

• '"'A ^ f .-' ',-1 -

. 5) 40"

- * " ' • ^ 40° SEA * Of JAPAN ••

•*' ^ YELLOW ' $ V • SEA •i^f* >'

•

'- • ^JT" ,?^ EAST • CHINA 25° SEA 25°

•' y^ '' rir • ,

•I PACIFIC OCEAN

I- ,' ; \ ^ V - Wm% PHILIPPINE \ i \ , SEA

SOUTH ^ t, •^ . CHINA > .V .^

10° ^ r ' » . 10° > >:'- •: • ^ Gulf . ^ . . '

A 'Thailand ^ V • .i •

• -.'-,— - « CELEBES

• ^ ' ^^ .^ ^. ^

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' ' - ; \ 5° 5°

k J^ VA SEA .. • " »'• •• ar-.fl ^-:3r- s. ^.^ "^ ^ • » -• • • ARAFURA X-^v ..^ --••, SEA 4 "TT -J. INDL^Af OCEAN .' J /t 300 600 900 1200 1500 km

100° 115° 130° fi'. WORLD ATLAS OF SEAGRASSES

THE SEX LIFE OF SEAGRASSES

Halophita rfec/p/ens female [rigtitl and male llefti

Posidonia oceanicj inflorescence with fruits, western f^editerranean. flowers, fvlalaysia

Enhalus acoroides in fvlalaysia and

Indonesia: female flowers labovel; pollen on

tlie water surface Irigfit, iopl. fruit Inght, Spadix of eelgrass, Zostera manna, with male

middlel, seed dispersal Ingtit. bottomi flowers releasing pollen

Posidonia australis fruit meadow. Western Australia. Jhatassia hempnchii fruit. !K // The Philippines and Viet Nam 183

The seagrasses of The Philippines and Viet Nam

are found extensively Seagrasses throughout the catch in the Philippines. A total of 1 384 individuals and Philippine Archipelago. There are documented 55 species from 25 fish families were identified from

sizeable beds offshore from western, north- five seagrass sites'". western and southern islands covering 978 km' at 96 Calumpong and Mefiez'*' describe two mixed well-studied sites. Approximately one third of this area species associations, one of Synngodium lor has been mapped in detail using a combination of sometimes Thalassia] with Cymodocea and Halodule remote sensing and field survey techniques. The spp., growing primarily on sandy sediment, the other of remainder is estimated. With many other areas not Enhalus and Thalassia spp. on muddy substrates. surveyed tor seagrasses, the total seagrass area is Monospecific seagrass beds are less common than likely to be many times greater mixed populations in the Philippines and tend to occur The Philippines is reported to have 15 species of under certain conditions: Enhalus acoroides colonizes seagrass"". In addition to Ruppia maritima and turbid, quiet, protected areas such as bays and Halophiia beccarii, Fortes lists a new variety of Halophila estuaries and Thalassia hemprichii occurs as pure minor''". Calumpong and Menez™ consider Halophila stands in the tidepools of the most northerly islands in beccariHo have been extirpated from Philippine waters, the Philippines"". Halophila decipiens grows primarily because the only specimens to be collected were in 1912 at depths of 11-23 m'". Thalassodendron ciliatum and from tvlanila Bay'", now heavily impacted by the growth Halophila spinulosa are found in deep, clear water'^'. of metropolitan Manila. Fortes disagrees, believing this Thalassodendron ciliatum also grows in shallow waters species still occurs in Manila Bay'^' and to be common in but only in conditions of low turbidity on coarse or rocky

Lingayen Gulf, northwestern Philippines. substrates'". Cuyo Island is the northernmost limit of

Many plants and animals live in the seagrass Thalassodendron ciliatum in the Pacific'^'. beds of the Philippines and Viet Nam, supporting The vital role of seagrasses as nursery grounds fisheries with their rich nutrient pool and the diversity and food for fish and invertebrates in the Philippines of physical structures protecting juveniles from has been appreciated for some time"". The rabbitfish, predators. Major commercial fisheries occur Siganus canaliculatus, is a voracious herbivore and immediately adjacent to seagrass beds""'. Fish and particularly important as a food species. In Bais Bay, shrimp are the most important elements of the Negros Oriental, the population of Siganus commercial fishery, although coastal villages derive canaliculatus consumes 0.64 metric tons per day from their sustenance from other components of the grass a 52-ha Enhalus acoroides meadow"^'. However, this beds. The major invertebrates found in the beds are represents less than 1 percent of the daily organic shrimps, sea cucumbers, sea urchins, crabs, scallops, production of Enhalus acoroides. Rabbitfish are often mussels and snails. Some endangered species of sea caught in seagrass beds using bamboo traps'", turtles reported in seagrass beds include the green sea representing a direct link between seagrass habitat and turtle, the olive Ridley, the loggerhead and the flatback. human subsistence.

In the Philippines and Viet Nam the sea cow [Dugong Seagrass beds in the Philippines are threatened dugon], which Is almost completely dependent on by eutrophication, siltation, pollution, dredging and seagrass, is an endangered species. unsustainable fishing methods. Many thousands of

Coral reefs and their associated seagrasses hectares of seagrass have been lost as a result of land potentially supply more than 20 percent of the fish reclamation for housing, airports and shipping 1

184 WORLD ATLAS OF SEAGRASSES

SeagrassNet team has clearly shown the impacts of

eutrophication at the site adjacent to a coastal town.

Seagrass-Watch is now established in . This community-based seagrass monitoring program

is coordinating with SeagrassNet to provide a second data stream, generated by volunteer members.

VIET NAM

There are 1 1 species of seagrass in Viet Nam distributed

along the coastline but mostly from the middle to the

southern sections. Their status is unknown though in general the Viet Nam coastal zone has been heavily impacted by sedimentation and domestic and agricultural pollution. Viet Nam has at least HO km' of seagrasses determined from remote sensing and

ground-truth surveys. Viet Nam is at the overlap of temperate and tropical seagrass species with Zostera

japonica growing intertidally in the north and mixing

with Halophila ovalis, while in the south the species

Spear-fisher over a seagrass bed in the Philippines. composition is similar to the Philippines and Malaysia.

facilities'". Some attempts have been made at AUTHORS

rehabilitating damaged seagrass beds using Miguel Fortes. Marine Science Institute CS, University of the Philippines,

transplanting techniques"". Diliman, Quezon City 1101, Philippines. Tel: + 63 1012 7205301. Fax: +63

Puerto Galera, a quiet ecotourist destination 1012 9247678. E-mail: mdfortesl38(ayahoo,com

south of Manila, is the site of one of the first

SeagrassNet global monitoring locations. Quarterly Ed Green, UNEP World Consen/ation Monitoring Centre, 219 Huntingdon

sampling of the seagrass habitat has been conducted Road, Cambridge CB3 DDL, UK.

at reference and impacted seagrass sites monitored by

graduate students from the University of the Fred Short, University of New Hampshire, Jackson Estuanne Laboratory,

Philippines. Even in the early stages of monitoring the 85 Adams Point Road, Durham, NH 03824, USA.

REFERENCES 9 Mernll ED [1912], A Flora of Manila. Philippine Islands Bureau of

Science Publication 5. Bureau of Pnnting, Manila. 490 1 Menez EG, Phillips RC, Calumpong HP [1983]. Seagrasses from the Number pp.

Philippines. Smithsonian Contributions to the Manne Sciences No. 10 Phillips RC, Menez EG [1988]. Seagrasses. Smithsonian Contributions to the Manne Sciences No. 34. 104 21. pp 1-40, pp. 2 Meiiez EG, Calumpong HP (1983). Thalassodendron ciliatum-. An 1 Calumpong HP, Menez EG, Phillips RC [1986], Seagrasses in

unreported seagrass from the Philippines. Micronesia 18: 103-111. Batanes Province, northern Philippines. S/i//manJourna/ 33(1-41:

3 Menez EG, Calumpong HP [19851. Halophila decipiens: An 148-154. unreported seagrass from the Philippines. Proceedings olthe 12 Dolar MIL [19911. A survey on the fish and crustacean fauna of the

Biological Society of Washington 98111: 232-236. seagrass beds in North Bais Bay, Negros Oriental, Philippines. In: Living in 4 Fortes MD [1990], Seagrass resources in East Asia: Research Proceedings of the Regional Symposium on Resources University of Philippines Marine Science status, environmental issues and management perspectives. In: Coastal Areas. the

A5EAMS/UNEP Proceedings of First ASEAMS Symposium on Institute, Quezon City, pp 367-377. Southeast Asian Marine and Environmental Protection. UNEP 13 Leptein MV [1992]. The gut passage rate and daily food consumption of the rabbitfish Siganus canaliculatus [Park]. In: Regional Seas Reports and Studies No. 116. pp 135-144. 5 Fortes MD [1986]. Taxonomy and Ecology of Philippine Seagrasses. Third ASEAN Science and Technology Week Conference

PhD dissertation. University of the Philippines, Diliman, Quezon Proceedings Vol. 6. National University of Singapore and National Science Technology Board, Singapore, 327-336. City. 245 pp. pp. 6 Short FT. Coles RG ledsl [2001] Global Seagrass Research 14 Calumpong HP, Phillips RC, Meriez EG, Estacion JS, de Leon ROD, Methods. Elsevier Science, Amsterdam. Alava MNR (19931. Performance of seagrass transplants in Negros

7 Fortes MD [1989]. Seagrasses: A Resource unknown in the ASEAN Island, central Philippines and its implications in mitigating shallow coastal areas. In: Proceedings of the 2nd RP- Region. ICLARM Education Series 5. 46 pp. degraded for 8 Calumpong HP. Menez EG [1997]. Field Guide to the Common USA Phycology Symposium/Workshop. Philippine Council Mangroves, Seagrasses and Algae of the Philippines. Bookmark, Aguatic and Marine Research and Development, Los Barios, Laguna, 295-313. Makati City, Philippines, 197 pp. pp

#^ Japan 185

17 The seagrasses of JAPAN

K. Aioi M. Nakaoka

Sixteen seagrass species, including seven temper- waters), namely Zostera asiatica, Zostera caespitosa, ate (Zosteraceael species and nine tropical , Zostera japonica, Phyilospadix species IHydrocharitaceae and Cymodoceaceae), iwatensis and Phyltospadix japonicud^''\ The region can occur on the coasts of Japan, about a quarter of the be regarded as a "hotspot" of seagrass floral diversity total number of seagrass species in the world (Table within the temperate waters of the northern

17.1). Species diversity is high not only for seagrasses hemisphere. Most of these species have limited but also for algal flora, w/ith about 1 500 species of distribution in some localities along the northern part algae occurring around Japan. Such a high species of Japan (see below). The hemispheric distributions in diversity in Japanese marine flora is probably related to the western Pacific may reflect the speciation process complex hydrodynamic properties around the Japanese of Zosteraceae from its possible ancestral origins in coasts that are affected by several major ocean equatorial regions''"'. currents such as the Oyashio cold current, and the Despite the high species diversity of Japanese Kuroshio and Tsushima warm currents. seagrasses, there are relatively few ecological studies

Among the 16 species of seagrasses in Japan, of these species with the exception of Zostera marina. nine belong to the families Hydrocharitaceae and After pioneer studies by Tomitaro Makino and Shigeru

Cymodoceaceae and are tropical species commonly Miki who described these species in the late 19th and found in tropical and subtropical areas of the Indo-West early 20th centuries, few seagrass studies were

Pacific region'". In Japan, their distribution is restricted conducted in Japan until the early 1970s. This is to the southwestern islands IRyukyu and Amami especially true for the endemic species of Zosteraceae islands) except for Halophila ovalis. In contrast, for which information on distribution and ecology was distribution of all the species of Zosteraceae is limited not available until recently, partly due to their to the main island areas, except for Zostera japonica occurrence in deep water Isee below). which also occurs in the Ryukyu Islands. Thus, the Eelgrass, Zostera marina, is a cosmopolitan seagrass flora in Japan differ distinctly between the species commonly found in temperate to subarctic subtropical southwestern islands and the temperate coasts in the northern hemisphere'". In Japan, Zostera coasts of the main islands. The southern limit of the marina occurs in numerous localities along the temperate species of Zosteraceae is determined by the coastlines of the main islands, i.e. Honshu, Hokkaido, summer high seawater temperature of 28°C around Kyushu and Shikoku'". The northernmost population of

Kyushu, while the distribution of tropical seagrass Zostera marina in Japan is found near Soya Cape, species is restricted by the winter seawater Hokkaido (45°30'N1'" and the southernmost population temperature of 15°C'^'. in Satsuma Peninsula, Kyushu (31°10'N)'". Most

Along the temperate coasts of China, the Korean eelgrass populations in Japan are perennial and extend

Peninsula and the islands of Japan, species diversity of their distribution both by clonal propagation of

Zosteraceae is high. In addition to Zostera marina, a rhizomes and by seed production, although an annual cosmopolitan species widespread in the northern form of Zostera marina is found in some localities such hemisphere in both the Pacific and Atlantic Oceans, six as Hamana-ko, Okayama and Kagoshima'"". species of the family Zosteraceae are present that are Zostera japonica is a small seagrass that considered to be endemic to the northwestern Pacific generally inhabits intertidal and shallow subtidal [Japanese, Korean, Chinese and southeast Russian bottoms along the coast of East Asia, from Viet Nam to 186 WORLD ATLAS OF SEAGRASSES

Sakhalin and Kamchatka. Russia" '"'. In Japan, Zostera Bay, on the Pacific coast of central Honshu'"^" "', and

japonica is found in various localities, such as Notsuke in Toyama Bay, on the Sea of Japan"^'.

Bay in the northeastern part of Hokkaido"", Toyama Zostera caespitosa was reported to occur in

Bay in the Sea of Japan"'"'", Sagami Bay on the Pacific Hokkaido, in the northern half of Honshu and on the coast of central Honshu"^' and the Ryukyu Islands, in east of the Korean Peninsula"". Populations of this the southwestern part of Japan"'"'*'. species were recently reported from Notoro Lake and Zostera asiatica was originally recorded by Miki Notsuke Bay in Hokkaido"""', Mutsu Bay, northern from southern Sakhalin iRussial, the northeastern and Honshu'", Yamada Bay and Otsuchi Bay. northeastern

southern parts of Hokkaido, in the central part of Honshu''" "', and Toyama Bay, in the Sea of Japan"". Honshu facing the Sea of Japan, and on the eastern Two Ptiyilospadix species. Phyllospadix iwatensis

coast of the Korean Peninsula"". In Japan, populations and Phyllospadix japonicus, inhabit the intertidal and

of Zostera asiatica are currently known only in subtidal rocky bottoms of temperate regions of Japan. Hamanaka and Akkeshi Bay, Hokkaido'^', and in Distribution of Phyllospadix iwatensis ranges from Funakoshi Bay, on the northeastern coast of Honshu'"'. Hokkaido to the northern part of Honshu. Phyllospadix Additionally, the stranded dead plants have been japonicus occurs in the central part of the Pacific coast

collected at several beaches in Hokkaido and one site in of Honshu and the western part of the Sea of Japan Toyama Bay" '". coast of Honshu'^"'. Zostera caulescens was known from limited Among the nine tropical seagrass species

localities along the central to northern coast of Honshu belonging to the families Hydrocharitaceae and and the southern coast of the Korean Peninsula when Cymodoceaceae, Halophila ovalis has the widest

Miki first described this species'"-'". Some recent distribution, occurring from the Yaeyama Islands to

papers report the existence of populations in Mutsu Chiba Prefecture lOdawa Bayl and to Toyama Bay, on Bay, northern Honshu'^', along the Sanriku coast, the Sea of Japan"". The distribution of the other eight

northeastern Honshu'^""', in Tokyo Bay and Sagami species is restricted to the Amami and Ryukyu Islands (Table 17.11. Detailed information on island-by-island

distribution of each species has been given'"' "^".

Table 17.1 Geographical distribution of these species

Seagrasses recorded in Japan overlaps widely, with multispecific seagrass habitats

commonly observed both in the temperate and tropical

Species Distribution regions of Japan. In Hokkaido, three species coexist in

a single bed in Notoro-ko [Zostera marina, Zostera

Hydrocharitaceae japonica and Zostera caespitosa] and in Akkeshi Bay

Enhalus acoroides Ryul(yu Islands [Zostera marina, Zostera asiatica and Phyllospadix

Thalassia hempnchii Ryukyu Islands iwatensis]. In Honshu, four seagrass species co-occur

Haloptiila decipiens Ryukyu Islands in Odawa Bay [Zostera marina. Zostera japonica,

Habphiia ovalis From Ryukyu Islands to Zostera caulescens and Halophila ovalis]'""' and in

central Honsfiu Otsuchi Bay IZostera marina, Zostera caespitosa, Zostera caulescens and Phyllospadix iwatensis], and

Cymodoceaceae three species co-occur in Funakoshi Bay IZosfera

Cymodocea rotundata Ryukyu Islands marina. Zostera asiatica and Zostera caulescens] and

Cymodocea serrulata Ryukyu Islands in lida Bay [Zostera marina, Zostera japonica and

Halodule pinifolia Ryukyu Islands Zostera caespitosa]. In the Ryukyu Islands, nine

Haioduie uninervis Ryukyu Islands species were found in a single seagrass bed in Iriomote

Syringodium isoetifolium Ryukyu Islands Island [Enhalus acoroides, Thalassia hemprichii, Halophila ovalis, Cymodocea rotundata, Cymodocea

Zosteraceae serrulata, Halodule pinifolia. Halodule uninervis,

Phyllospadix malensis North Honshu and Hokkaido Syringodium isoetifolium and Zostera japonica]"^'; eight

Phyllospadix laponicus South Honshu species were found in some beds at Ishigaki Island, "'". Zostera asiatica Hokkaido and north Honshu Miyako Island and Okinawa Island'"

Zostera caespitosa Hokkaido and north Honshu

Zostera caulescens Central and north Honshu BIOGEOGRAPHY

Zostera japonica From Ryukyu Islands to The depth range of seagrasses in Japan is reported for

Hokkaido some multispecific seagrass beds where two or more

Zostera marina From Kyushu to Hokkaido species coexist in a single bed'^". Generally, each

species in the mixed beds shows a different depth <

Japan 187

distribution, forming some specific patterns of zonation ^^O'E RUSSIAN ^r-^ FEDERATION along depth gradients. s.^idrv >. , ,.

Among Zostera spp. in temperate muUispecific Hokkaido ^, Mamanato • * seagrass meadows, Zostera japonica is always found in •l^' ^-^ ]'ltJit'shi Bin tfie uppermost parts of tfie bed, as its mam habitat is r0— Mulsu Buy intertidal flats. Zostera marina occurs in the shallowest maJu Buy uniikoshi Buy parts of subtidal beds, mostly between 1 and 5 m deep, Oisuchi Ba\ but in some places down to 10 m. Zostera asiatica i REP OFt \faizuniBaY * Honshu YELLOW KOREA/ Toltyo, JAPAN SEA T *J„-Vr'' occurs between the intertidal zone and a depth of 5 m. ^ "^OJinx a Ben Two other species generally occur in deeper habitats .Sa^uiniBtn r'Shikoku'K ci.1, i„ \ Kyushu namana-ko than Zostera marina: Zostera caespitosa. between 1 Sclu Inland Sea Kagoshima'^ •• and 20 m, and Zostera caulescens, between 3 and 1 7 m. EAST CHINA • In most of the mixed seagrass beds, the plants' depth SEA PACIFIC OCLA\'

Amami Is. ranges overlap to some degree with Zostera marina. J Ryukyu Is. •

Depth zonation in Zostera asiatica. Zostera caespitosa Okiruw;] hhrul 200 4O0 600 Kilomelers ••Yaeyama Is and Zostera caulescens cannot be described since ^ these species do not generally co-occur Map 17.1

In multispecific seagrass beds in the Ryukyu Japan

Islands, Haloduie pinifolia. Cymodocea rotundata and

Ttialassia hemprichii are dominant in the intertidal to Peninsula Ithe Sea of Japan coast)"". For Zostera upper subtidal zone, while Cymodocea serruiata and asiatica at Akkeshi Bay, Hokkaido, biomass 1427 g dry Entialus acoroides are more abundant in the deeper weight/m'l was twice that of Zostera marina, whereas subtidal zone'^'-'^'. The observed depth distribution of the shoot density 1134 shoots/m^l was about half of these species generally agrees with those reported in Zostera marina when comparing monospecific stands other parts of the tropical Indo-West Pacific region'''^ '". at the same depth, reflecting the larger shoot size of

Quantitative studies on biomass, shoot density, the former'"'. The above-ground net production of shoot size and productivity have been conducted in Zostera asiatica was estimated to be 3-5 g dry about 30 seagrass beds in Japan''"'. Biomass, shoot weight/mVday density and shoot size of Zostera marina vary greatly Information on the flowering and fruiting seasons among and within populations. Within populations, of Zostera marina and other Zostera species is biomass, shoot density and shoot size have sometimes available from some localities in Japan"". In Zostera varied more than twofold, with greater biomass marina, seasons for flowering and fruiting vary by 2-4 generally observed in shallower parts of seagrass months across the region, with early flowering and beds''''"'. Biomass as high as 500 g dry weight/m^ was fruiting observed at lower latitudes. Seed germination recorded in some areas such as Notsuke Bay, Otsuchi of Zostera marina was generally observed during the

Bay, Ushimado and Maizuru Bay, whereas maximum winter in southern populations and during spring in biomass was less than 200 g dry weight/m'' for northern populations. For other Zostera species, populations in Odawa Bay, Yanai Bay and Toyama flowering and fruiting seasons have been reported only Bay''"'. Estimates for above-ground net production were from limited localities, and vary greatly among available for several Zostera marina populations, and varied between less than 1 g to 13 g dry weight/mVday at different sites, depths and seasons. Between-site variation in these parameters did not appear to be correlated with variations in latitude or geographical > / distances. Quantitative information on abundance and productivity is very sparse for other species of Zostera, and for the tropical seagrass species, in Japan.

Biomass of Zostera japonica \/ar\es greatly with season; ~' a maximum biomass of 270 g dry weight/m' was 'm^^ V !4K;: _.\U ' recorded in July and a minimum of 30 g dry weight/m^ from December to January at Mikawa Bay, the Pacific side of central Honshu"". For Zostera caespitosa. maximum above-ground biomass of 60 g dry weight/m^ was recorded for the population in lida Bay, Nolo Meadow of Zostera caespitosa at Yamada Bay, Japan. W 188 WORLD ATLAS OF SEAGRASSES

localities. For Zostera asiatica and Zostera caulescens, the historical distribution of seagrass beds. In Tokyo

the flowering and fruiting seasons are generally the Bay, an old chart issued in 1V08 shows the distribution same as those of coexisting Zostera marina, whereas of Zostera marina and Zostera japonica in the early Zostera caespitosa flowers and fruits about one month 20th century. Extensive seagrass meadows of

earlier than sympatric Zostera marina"'''. approximately 3-5 km' in area were located in shallow

waters (<3 ml in some localities such as Yokohama,

HISTORICAL PERSPECTIVES Tokyo, Funabashi and Chiba'"'. Unfortunately, all these

Although seagrasses have been very familiar to, and seagrass beds were destroyed in land reclamation

traditionally utilized by. Japanese people living in (filling and hardening of the shorelinel projects during

coastal areas, very little information is available about industrialization in the mid-20th century.

Traditional uses of seagrasses in Japan include

direct use as fiber for rope or padding (e.g. cushions

Table 17.2 and tatami matsi or use as agricultural compost (Table

Traditional uses of seagrasses in Japan 17.21. Besides those listed, there may well be further traditional uses. For example, eelgrass was named

Traditional use Species Locality moshiogusa in Japanese, which means salt grass, and

Rope for gill net Phyllospadix iwatensis Hol(l

Cushions for horse Zostera manna Sannku

saddles IMiyagi Pre.l ESTIMATES OF HISTORICAL LOSS AND PRESENT

Fishermen's skirts Phyllospadix malensis Sannku COVERAGE

and Zostera marina llwate Pre.l The area of seagrass beds, especially those consisting

Cushions for train Zostera manna Tokyo Bay area of eelgrass Zostera marina, has declined since the

seats 1960s, mainly because of land reclamation. During

Tatami mats Zostera manna these last decades, the Japanese economy has

Agricultural compost Algae and Miura Peninsula developed rapidly. The Environment Agency of Japan

Zostera marina IKanagawa Pre.l surveyed the status of algal and seagrass beds along

Agricultural compost Algae and Zostera Hamana-ko most of the coastal areas of Japan in 1978 and again in

manna IShizuoka Pre.l 1991, from which the loss during this period was

Agncullural compost Zostera marina Mikawa Bay estimated (Table 17.31. The total area of algal and

Agricultural compost Zostera manna Seto Inland Sea seagrass beds together was 3262 km' in 1978 and

jOkayama Pre.l 3 159 km' in 1991. For seagrass beds, the total area

Agncullural compost Zostera marina and Nakaumi declined from 515 km' to 495 km' during the period, i.e.

freshwater plants IShimane Pre.l about 4 percent of Japan's total seagrass resource was

lost in 13 years. In particular, more than 30 percent of

Note: Pre, = Prefecture, Zostera marina beds disappeared in localities such as

Ariake Bay, Kagoshima Bay and Hyuga-nada in Kyushu

during this period'". In the Seto Inland Sea, more than

70 percent of Zostera marina beds have been lost since

Table 17.3 1977, a loss which has seriously affected coastal

Estimates of total areas of algal and seagrass beds in fisheries""'.

Japan in 1978 and 1991. and the percent area lost during For regionally endemic species of Zostera, the

the period situation may be more serious than for Zostera marina,

because populations are now known to exist in only a

Area of macrophyte Area lost % few localities around Japan. In fact, Zostera asiatica and

beds Ikml Ikm^l lost Zostera caulescens are now ranked as VU (vulnerable

1978 1991 stagel in the Red Data Book of threatened Japanese

Algal beds* 2748 2664 83 3,0 plant species"". Among tropical seagrass species,

Seagrass beds 515 495 21 4,0 Enhalus acoroides and Halophila decipiens are found

Total 3263 3159 104 3.2 only in limited localities in the Ryukyu Islands, and they

are also listed as VU in the Red Data Book.

Note: * Algal beds consisted of Utva. Enteromorpha,

Sargassum. Laminana, Eisenia and Gelidium.. PRESENT THREATS As described above, seagrasses have been

Source: As reported by the Japanese Environment Agency in 1994, disappearing rapidly due to industrial development in the coastal regions of Japan. Major threats for further w Japan 189

Case Study 17.1 AKKESHI, EASTERN HOKKAIDO

In Hokkaido, the northernmost island of Japan, some healthy Zostera manna beds remain. At

Akkeshi U2°50'N, Ui°50'El, located in eastern

Hokkaido, extensive seagrass meadows occur in

Akkeshi-ko la brackish lagoonl adjacent to Akkeshi

Bay. In Akkeshi-ko, the dominant seagrass is Zostera manna with minor amounts of Zostera japonica. A large-scale study was recently initiated

here to examine the interactions between terrestrial

and coastal ecosystems"". It was found that

considerable amounts of nutrients of terrestrial origin flow into this lagoon and these are important

for the productivity of Zostera manna and associated

communities. Studies on food web dynamics in the Zostera manna bed have revealed that the major consumer of Zostera manna was the whooper swan

[Cygnus cygnus] which overwinters in the lagoon, and that mysids are the most dominant herbivores grazing on epiphytic algae on eelgrass"'™. Both the

biomass and the diversity of mysids are high, and

this supports high productivity of commercially important fish and shellfish species such as

epifaunal shrimps and several species of fish'™'. Zostera manna leaves coated with epipfiytes

decline in present seagrass coverage include land habitats in February 2002. Scientists and non- reclamation, environmental deterioration such as governmental organizations in Japan must support and reduced water quality, and rise in water temperature collaborate in these surveys to save the dugongs and and water level due to global warming. conserve their habitats. The loss of seagrass vegetation over the last two Some seagrass beds have been declining rapidly decades along the Japanese coast is mostly attributed even in areas where no major land reclamation has to land reclamation"". Many land reclamation projects occurred, such as the Seto Inland Sea. In these areas, are still ongoing or at the planning stage, and will water pollution and disturbance of habitats by fish probably further accelerate the loss of seagrass beds. trawling are major causes of decline in seagrass beds.

For example, the coastline has been damaged by land In the case of multispecific seagrass meadows, reclamation and port construction in the Ryukyu changes in environmental conditions due to human Islands where large economic investments have been activities have effects not only on overall seagrass made toward rapid modernization. The natural distribution and abundance but also on the species ecosystems of coral reefs and lagoons were greatly composition of the seagrass beds. In Odawa Bay near impacted, especially along the coasts of Okinawa the Tokyo metropolitan area, for example, reduced light

Island. Dugongs inhabit several seagrass beds in the condition due to eutrophication over the past 20 years northeastern coast of Okinawa Island, which is the caused a decrease in areas of Zostera marina in northern limit of global distribution of this threatened shallow habitats, but possibly favored the deeper-living marine mammal. Nevertheless, a large-scale land Zostera caulescens to expand its populations into reclamation project is now planned in the center of the shallower depths"^'. However, due to lack of species- seagrass beds (Henoko coral lagoonl to build an by-species data in past literature, it is not possible to offshore runway for the US air base. Such construction determine whether Zostera caulescens truly increased would almost certainly be fatal to the lagoon ecosystem in recent years. Long-term field surveys of seagrass and directly destroy seagrass habitats for dugongs. The beds using a unified approach are necessary in order to

Environment Agency of Japan decided to make a monitor future changes in seagrasses in relation to general survey of the northernmost dugongs and their changes in environmental conditions.

Il 190 WORLD ATLAS OF SEAGRASSES

Case Study 17.2 RIAS COAST IN IWATE PREFECTURE, NORTHEASTERN HONSHU

Five temperate seagrass species. Zostera manna, technique to estimate overall distribution and

Zostera caulescens, Zostera caespitosa, Zostera abundance of seagrasses'^". The survey in

japonica and Phyllospadix iwatensis, occur in the Funakoshi Bay has shown that the areal extent of the three bays along the Rias Coast facing the seagrass bed was approximately 0.5 km' with the northeastern Pacific, namely Yamada Bay, depth distribution extending from 2 to 17 m.

Funakoshi Bay and Otsuchi Bay, in Iwate Prefecture. Variation in canopy height of Zostera caulescens by The species composition of seagrasses vanes depth was also analyzed from the echo-trace of the

among the bays. In Yamada Bay, Zostera caespitosa sounder The same technique has been utilized to

is the most abundant, with Zostera manna co- estimate the abundance of Zostera caespitosa in

occurring. The dominant species in the seagrass Yamada Bay and to monitor long-term changes in

bed in Funakoshi Bay is Zostera caulescens with patch dynamics of a seagrass bed at a river mouth

small patches of Zostera marina and Zostera on Otsuchi Bay

asiatica occurring at the shallower part of the bed. In the seagrass bed at Funakoshi Bay, Zostera

Zostera caulescens. Zostera marina and Zostera caulescens develops a high canopy at the deeper

caespitosa are found to coexist m several seagrass parts of the bed l>10 ml by extending long flowering

beds in Otsuchi Bay shoots. A maximum shoot height of 6.8 m was

A large-scale census of these seagrass beds recorded in 1998, known as the world's record

has been undertaken using an acoustic sounding longest among all seagrasses'^''. In July 2000, an

even longer shoot (7.8 ml was found at the same

site. Studies of the dynamics and production of the

Zostera caulescens population revealed that most of

the flowering shoots emerge in winter and grow

rapidly, reaching an average height of 5 m in late summer'^". Annual above-ground net production per

area was estimated to be ^26 g dry weight/m7year, similar to estimates for other Zostera species that

live in intertidal and shallow subtidal beds (<1 m

deepl. Thus, the productivity of Zostera caulescens

is quite high despite its distribution in deep water li- 6 ml with poor light conditions. Comparative morphological and phenological studies of Zostera caulescens between Iwate and Sangami Bay Inear

Tokyol showed that the large differences in shoot height and seasonal dynamics are probably related

to differences in environmental factors such as temperature'"'.

In these seagrass beds, the abundance and

dynamics of associated communities have been

investigated for epiphytic algae'^^', sessile epifauna'*", mobile epifauna'"'*^'"' and benthic

infauna'"'. The dynamics of these organisms are greatly influenced by spatial and temporal variations

in seagrass abundance. Most interestingly, a species

of tanaid crustacean [Zeuxo spl was found to feed on predispersal seeds of Zostera marina and Zostera caulescens'^"'. The crustacean consumes up

to 30 percent of the seeds, which may have a large

Tfie world's longest seagrass, Zostera caulescens. at 10 m negative impact on the seed abundance of the

deep in Funakoshi Bay seagrasses.

'AW 1

Japan 191

The global circulation of ocean currents is ACKNOWLEDGMENTS important not only for land vegetation but also for We thank Y. Tanaka and M. Watanabe for providing information and marine plants, as distributions of temperate and photographs of Japanese seagrasses, and N. Kouchi and F.T Short for tropical seagrass species are restricted by seawater reviewing the manuscript. temperature in summer and winter, respectively, along the Japanese archipelago. Most physicists and meteor- AUTHORS ologists believe that the seas have warmed from 2°C to Keiko Aioi, Aoyama Gakuin Women's Junior College, Shibuya 4-4-25,

5°C over the past 50 years due to global warming. Shibuya, Tokyo 150-8366, Japan. Tel/fax: +81 1013 3313 1296, E-mail:

Global warming is predicted to affect the photosynthetic aioi357(agalaxy ocn.ne.jp activities of marine plants in Japan. A further warming of 2 or 3°C in the seawater temperature may prove fatal Masahiro Nakaoka, Graduate School of Science and Technology, Chiba to seagrass beds in shallower areas'"'. Shallow water University, Inage, Chiba 263-8522, Japan. vegetation such as seagrass and algae along the coasts of Japan is also at risk of accelerated loss due to water level rise caused by global warming.

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with English abstract!. 4!;uat/ceo(any 72: 99-106. The Republic of Korea 193

18 The seagrasses of THE REPUBLIC OF KOREA

K.-S. Lee

S.Y. Lee

Korean peninsula, located at the eastern end Sea is connected to the and the Theof the Eurasian continent, lies between 33°N and Tsushima current, a branch of Kuroshio, flows towards

i3°N. The total coastline of the peninsula, the East Sea through the South Sea. The coastline of including the coastlines of the islands, reaches the South Sea is also heavily indented. Tidal ranges on

17000km. About 3^00 islands are distributed along the the south coast vary from about 1.0 m in the east part coasts of the Republic of Korea. Since each coast shows of the coast to about 4.0 m in the west part. The East very distinct characteristics, seagrass habitat Sea is deeper than the Yellow Sea or the South Sea, and properties also vary. The west and the south coasts the eastern coastline is very simple and linear Tidal have highly complex and indented coastlines, while the range is usually less than 0.3 m. east coast has a simple and linear one. Sand dunes are well developed, and several lagoons are formed on the PRESENT SEAGRASS DISTRIBUTION east coast of the peninsula. Tidal flats are located at Eight temperate seagrass species are distributed on several places on the south coast. Tidal range is 1-4 m the coasts of the Korean peninsula. Zostera marina is on the south coast and higher along the west part of the the most abundant seagrass species, widely distributed coastline. About 2000 islands are distributed in the throughout all coastal areas (Table 18.2] in relatively western part of the south coast. Although the linear large meadows. Zostera asiatica is mostly distributed distance of the west coast is some 650 km, the actual in the cold and temperate coasts of northeastern Asia. length of the coastline is about 4700 km. Tidal range is In the Republic of Korea Zostera asiatica occurs on the extremely high on the west coast of the Korean east coast; the distribution of this species on the west peninsula; maximum tidal range is about 10 m on this and the south coasts of the Korean peninsula is not coast. Very large tidal flats are formed because of the clear Zostera caespitosa, Zostera caulescens and flat sea bottom and high tidal range. Zostera japonica are found on all the Republic of

Eight temperate seagrass species, five Zostera, Korea's coasts (Table 18.2]. two Phyilospadix and Ruppia maritima, are distributed Two Phyllospadix species, Phyltospadix iwatensis on the coasts of the Korean peninsula" ". Although and Phyllospadix japonicus, are found on Korean seagrasses are relatively abundant, few studies have coasts'^'. Phyllospadix japonicus occurs on all coasts of reported on their physiology and ecology in this area the peninsula, while Phyllospadix iwatensis occurs on and most of these reports were written In the Korean the east and west coasts. On the east coast, language. In this paper, we review the status, habitat Phyllospadix iwatensis usually appears In the northern characteristics and ecology of seagrasses on the coasts parts of the coast, while Phyllospadix japonicus is of the Republic of Korea. distributed in the southern parts. Distribution of Ruppia

The Korean peninsula is enclosed by the Yellow maritima in the Republic of Korea has been reported

Sea Ito the west of Korea], the South Sea and the East from limited areas on the west and south coasts"*'. Sea, which have considerably different characteristics (Table 18.11. The coastline of the Yellow Sea Ithe west BIOGEOGRAPHY OF THE REGION coast] shows a heavily indented coast with maximum Seagrasses are distributed In numerous locations tidal range of about 10 m. The hydrographic properties along the coast of the Korean peninsula with habitat and circulation characteristics of the Yellow Sea are types varying among the different coasts (Table 18.31. strongly Influenced by climatic conditions. The South Seagrasses are widely distributed throughout the south 194 WORLD ATLAS OF SEAGRASSES

Table 18.1

Physical characteristics of seagrass beds on the west, south and east coasts of the Republic of Korea

Characteristics West coast South coast East coast

Wave energy Low Low High

Sediment Muddy sand Muddy sand Sand

Tidal range Iml 3-10 1-4 0.1-1

Coastline Heavily indented Heavily indented Simple linear

Seagrass habitat Bays, islands Bays, islands Lagoons, bays

coast, wtiile on the east coast, where the wave energy is IS mainly distributed in the intertidal zone around

high, the distribution of seagrasses is limited to islands. lagoons, ports and barrier reefs. On the west coast, Both Phyllospadix species, Pt)yiiospadix iwa-

seagrasses are mainly distributed in the intertidal and tensis and Ptiyllospadix japonicus, occur mainly on

subtidal zones of islands. Seagrasses usually form rocky substrata along the east coast of the Korean small patches on the east coast, while large seagrass peninsula. Although Phyllospadix spec'tes are observed

meadows occasionally occur on the west and the south in both sheltered and open shores, they usually grow in coasts of the Republic of Korea. high-energy environments. Distribution of Ruppia

Zostera marina appears at the intertidal and maritima has been reported from a few estuaries on

subtidal zones, where the water depth is usually less the west and the south coasts. However, the Ruppia than 5 m, and forms relatively targe meadows. Zostera maritima habitats have been severely disturbed

marina can be observed in both muddy and sandy recently, so the present distribution of this species

sediments'". Zostera asiatica is distributed in relatively should be investigated. Although a few mixed beds with

deep water 19-15 ml in bays or along open shores, and Zostera marina and Zostera japonica occur on the west

forms small patches. Zostera asiatica is usually coast, different seagrass species do not usually coexist

observed in sandy sediments along the east coast. in the Republic of Korea.

Zostera caespitosa also usually forms small patches The vegetative shoot height of Zostera marina in

and is distributed in deeper water 13-8 ml than Zostera the Republic of Korea ranges from 30 cm to 210 cm

marina. Zostera caespitosa occurs on all coasts of the (Table 18. Al, and varies significantly among habitats.

Korean peninsula, but is limited to a few areas with Reproductive shoots, which are usually taller than mixed sediments of sand and gravel. Zostera vegetative shoots, range from 50 cm to 350 cm. The leaf

caulescens is distributed on both sandy and muddy width of Zostera marina also shows significant

bottoms. As a result of its height, Zostera caulescens variation according to environment. Some plants from

usually occurs in deep water 16-12 ml. Zostera japonica eelgrass beds on the east and the south coasts have

Table 18.2

Seagrass species distributed on the coasts of the Republic of Korea

Species Distribution

West coast South coast East coast

Genus Zostera \

Zostera marina / / /

Zostera asiatica ? ? J

Zostera caespitosa / / / Zostera caulescens / / / Zostera japonica / / /

Genus Phyllospadix

Phyllospadix iwatensis / Phyllospadix japonicus • • / Genus Ruppia

Ruppia maritima ?

Ti^fclJ. N 6

The Republic of Korea 195

very wide leaves (about 15 mm|. Zostera marina in the 30 60 90 Kitometefs DEMOCRATIC PEOPLFS Republic of Korea has 5-1 1 leaf veins. REPUBUC OF KOREA The shoot heights of Zostera asiatica are 50-90 cm 38" N -X~ for vegetative shoots and 60-80 cm for reproductive shoots. Leaf widths range from 11 to 15 mm, and the EAST SEA leaves have V-11 veins (Table 18.^1. The shoot height of (SEA 01- JAfANl Zostera caespitosa tor both vegetative and reproductive shoots ranges from 50 cm to 170 cm. Zostera caespitosa REPUBLIC has relatively narrow leaves (5-8 mm wide], and usually YELLOW !,>- OF KOREA

5 leaf veins. Zostera caulescens is a very tall seagrass • i 36' species; the height of its reproductive shoot reaches 7-8 m. Zostera caulescens has wide leaves (10-16 mm) and 9-11 leaf veins. Zostera japonica is a very small Kwangycmg Bay seagrass species, usually less than 30 cm tall, with 3 leaf veins. The leaf width of Zostera Japonica is 1 -2 mm. Phyllospadix iwatensis and Pliyllospadix '• "> ' Tsushima t^tA^»>,"' japonicus show several morphological differences. The V/..*3'jU 41^ (JAPAN) shoot heights of both Phyllospadix species range from 34' Korew^' Strati

20 cm to 100 cm. Phyllospadix iwatensis has 5 veins in SOUTH SEA >:sW the lower portion of the leaf, but only 3 veins in the ^^'^ Cheju Do JAPAN apical portion'^'. Phyllospadix japonicus has 3 leaf veins. A The leaf width of Phyllospadix japonicus ranges from 126" E 130" E

1.5 mm to 2.5 mm, while the width of Phyllospadix Map 18.1 iwatensis ranges from 2.0 mm to A.5 mm. Republic of Korea

Table 18.3

(Habitat characteristics of seagrass species in the Republic of Korea

Species Sediment type Wave energy Water depth (ml Location

Zostera marina Muddy, sandy Low 0-5 Bay, lagoon

Zostera asiatica Sandy Intermediate 9-15 Bay, open shore

Zostera caespitosa Gravelly Low 3-8 Bay

Zostera caulescens Muddy, sandy Low 6-12 Bay

Zostera japonica Muddy, sandy Low Intertidal zone Bay

Ptiyltospadix iwatensis Rocky High 0-3 Open shore

Phyllospadix japonicus Rocl(y High 0-3 Open shore

Ruppia maritima Muddy, sandy Low 0-2 Estuary

1

Table 18.i

Morphological characteristics of seagrasses distributed in the Republic of Korea

Species Shoot height cml Leaf width (mm) Number of leaf veins

Vegetative Reproductive

Zostera marina 30-210 50-350 5-15 5-11

Zostera asiatica 50-90 60-80 11-15 9-11

Zostera caespitosa 50-170 50-170 5-8 5-7

Zostera caulescens 90-200 150-800 10-1 9-11

Zostera japonica 15-40 10-20 1-2 3

Phyllospadix iwatensis 20-100 - 2-4.5 5

Phyllospadix japonicus 20-100 - 1.5-2.5 3 ^ m 196 WORLD ATLAS OF 5EAGRASSES

Case Study 18.1 University], Dr Oh (Kyungsang National University! RECENT RESEARCH ON and Drs Choi and Lee (Hanyang University! are SEAGRASSES conducting taxonomic studies. Drs Choi and Lee have conducted a molecular phylogenetic study to

Few biological and ecological studies have been examine the phylogeny of the Zostera species in the

conducted on seagrasses of the Korean peninsula. Republic of Korea. The sequences of the internal

Recently, the Government of the Republic of Korea transcribed spacer IITSI regions in nuclear

began to realize the ecological and economic ribosomal DNA have been determined for five

importance of seagrasses in coastal and estuarine Zostera species in the Republic of Korea. From the

ecosystems. There is now an effort to preserve study, Zostera manna and Zostera caespitosa were seagrass habitats and to restore disturbed and the most closely related species, and Zostera

destroyed habitats. Since there is little physiological japonica was the most distinctive Zostera species.

and ecological information on seagrasses in the Dr Hong llnha University! is investigating

Republic of Korea, basic research on seagrass benthos in seagrass beds on the south and west

biology and ecology is necessary for efficient coasts of the Korean peninsula, Dr Huh IPukyung

management and restoration of seagrass habitats National University) and Dr Kim (Chonnam National

on the Korean coast. University! are studying fish populations and

Most seagrass research in the Republic of phytoplankton communities in seagrass beds. Dr K.

Korea, except for taxonomic studies, has been Lee jPusan National University) is conducting basic

conducted during the past few years. Current physiological and ecological studies on seagrass in

seagrass research projects are as follows: Or Choi the Republic of Korea, and research into carbon and

(Ajou University), Dr Shin ISoonchunhyang nutrient dynamics in seagrass beds.

Few studies on seagrass ecology have been juveniles of big fish species. Fish species abundant in

reported from the Korean peninsula. Therefore, few seagrass beds include Sgnattiynus sclilegeli, Ptiolis

data exist concerning seagrass biomass or productivity. sp., Pseudoblennius cottoides, Sebastes inermis and

The density, biomass and productivity of seagrasses Acanthogobius flavimanu^"'". Juveniles of economi-

change significantly with environmental conditions cally valuable fish species such as Sebastes inermis, such as water temperature, underwater irradiance and Platycephalus indicus and Limanda yoifoiiamae, nutrient concentration. Since water temperature along Acanttiopagrus sclilegeli and Lateolabrax japonicus

the coasts of the Korean peninsula shows obvious grow in seagrass beds, in seagrass beds on the south seasonal variation, being less than 10°C during winter coast, Acanthopagrus schlegeli were not observed and about 25°C during summer, seagrass biomass and during winter and spring. However, many small-size productivity also show significant seasonal variations. juveniles Hess than 3 cm body length) of Acanthopagrus

The shoot density of Zostera marina varies from about schlegeli were found in July; then they were seen

50 shoots/m' to 300 shoots/m'' depending on infrequently in October when their body length reaches

environmental conditions. Shoot densities of Zostera about 6 cm""'. Sebastes inermis. which is a very

caulescens and Zostera japonica are about 120 valuable fish species in the Republic of Korea, also

shoots/m' and about 8000 shoots/m', respectively, migrates into seagrass beds when its body size is about

during the summer months on the south coast'". 2 cm and spends its juvenile stage in seagrass beds.

Biomass of both Zostera marina and Zostera There are seasonal variations in the species

caulescens on the south coast is about 500 g dry composition and abundance of fish populations in weight/m^ during summer months, while Zostera seagrass meadows. A peak of fish abundance occurs

japonica has about 200 g dry weight/m^ Leaf during spring, with a secondary peak during the fall'^'.

productivity is about 2 g dry weight/mVday for Zostera The peaks are probably caused by increased larval

marina and Zostera caulescens. and about 5 g dry recruitment. Seasonal variation in fish species

weight/mVday for Zostera japonica during summer composition is closely related to standing crops of months. The small seagrass species Zostera japonica seagrasses"".

has higher leaf productivity because of its much higher A peak of shrimp abundance occurs In the late

shoot density. winter and spring"^'. Shrimp species in seagrass beds

More than 60 fish species can be observed in were most diverse during the late summer, and least

seagrass beds in the Republic of Korea; fish collected diverse during the late fall. Crab species in seagrass in seagrass beds are primarily small fish species or beds were most abundant during summer, and most The Republic of Korea 197

diverse during spring and summer"". The dominant observation and verbal information obtained from

group of benthic macrofauna in seagrass beds was fishermen. Most large seagrass beds in the Republic of

polychaete worms"". About 15 epiphytic algae species Korea were located in the bays of the south coast. Many

on seagrass leaf tissues have been reported from of these bay areas are now urbanized, so bay water is seagrass beds in the Republic of Korea. The dominant highly over-enriched by anthropogenic nutrients. Most epiphyte species are CallophyUis rhynchocarpa and seagrass has disappeared from these eutrophic bays.

Champla sp. during spring and summer, and Numerous former tidal flats and seagrass habitats on

Polysiphonia japonica and Lomentaria hakodatensis the south and west coasts of the Republic of Korea have during fall and winter Epiphyte biomass is lowest during been reclaimed for factory sites, residential districts or summer, and highest during winter Epiphytic algae agricultural land. Large areas of seagrass have been account for approximately 15 to 20 percent of total plant lost due to reclamation, particularly from the west and standing crop of the seagrass beds in Kwangyang Bay"^'. south coasts. For example, a large Zostera marina bed

113.6 km') existed in front of Kaduk Island, on the south USES OF SEAGRASSES coast of the Republic of Korea, until the late 1980s"'. Seagrasses are rarely used either directly or indirectly However, this eelgrass bed disappeared after in the Republic of Korea. Seagrasses have been reclamation of the adjacent mud flats during the considered as useless weeds around ports and boat early 1990s. channels and in shallow fishing grounds; fishermen cut Many oyster and seaweed farms are located in off seagrasses to have a better waterway. However, shallow coastal waters, where seagrasses exist. Lots of fishermen and the Government now realize the seagrass beds were destroyed by the construction and ecological and economical importance of seagrasses maintenance of these farms. Seagrass areas in the for fisheries and coastal ecosystems in the Republic of Republic of Korea also have been lost to boat traffic,

Korea. We are trying to use seagrass for conservation trawling and clamming. From the estimates of and restoration of coastal ecosystems. The coasts of the Korean peninsula have been highly disturbed and polluted as a consequence of industrial development Table 18.5 since the 1970s. Additionally, an expanse of tidal flats Ihe estimated areas of seagrasses distributed on the coasts and seagrass habitats has been reclaimed for factory of the Republic of Korea sites or residential districts. These coastal distur- bances have led to a reduction in spawning grounds and Species Area Ikm'l nursery areas for economically valuable fish, and Zostera marina 50-60 consequently led to decreases in coastal fish Zostera asiatica <1.0 production. Concrete constructs have been added to Zostera caespitosa 1.0 coastal waters in the Republic of Korea for artificial Zostera caulescens 1.0-5.0 fish-breeding reefs. Most artificial fish reefs were Zostera japonica 1.0 constructed in deep water, so few types of seaweed can Ptiyllospadix iwatensis <1.0 grow on the construct, and the construct provides Phyllospadix japonicus 1.0-2.0 habitat for only adult fish. However, seagrass beds can Ruppia maritima <1.0 provide a good fish spawning ground and nursery area Total 55-70 for juvenile fish, so we are now trying to restore seagrass habitats on Korean coasts. Seagrasses will also be used as a nutrient filter to reduce algal blooms, potential seagrass area and present seagrass especially red tide, which damage coastal fisheries in coverage, and verbal information from fishermen, we the Republic of Korea almost every year believe that more than 50 percent land maybe as much

Seagrass leaf detritus piled up on the beach is as 70 or 80 percent) of the seagrass area in the collected in some coastal areas to make compost, Republic of Korea has been lost since the beginning of which is used for fertilizing agricultural land. In earlier industrial development during the 1970s. times, children in the coastal zones chewed seagrass Most of the seagrass area in the Republic of rhizomes for their sweet taste. Korea is located on the south coast, and Zostera marina

beds account for about 90 percent of total seagrass

ESTIMATES OF HISTORICAL LOSSES AND PRESENT coverage in the Republic of Korea. Our estimated area

DISTRIBUTION of Zostera marina on the coasts of the Korean

There are no studies of seagrass areas in the Republic peninsula is about 50 to 60 km' (Table 18.5). The of Korea. Therefore, we must estimate historical losses estimated area for Zostera caulescens is 1 to 5 km'. and present seagrass coverage using personal Most Zostera asiatica and Ptiyllospadix iwatensis beds

J,^i 198 WORLD ATLAS OF SEAGRASSES

are found on the east coast; the estimated area tor both seaweed farming, and fishing activities such as

species IS less than 1 km'. Most Phyltospadix japonicus clamming and trawling, are also serious threats to beds are also found on the east coast, and the bed area Korean seagrasses.

is estimated at 1 to 2 km'. The estimated area for

Zostera caespitosa and Zostera japonica is about 1 km' POLICY

(Table 18,51. There is no information on the area of There is no policy which directly serves to protect

Ruppia maritima in the Republic of Korea, but it is seagrasses in the Republic of Korea. However, several

probably less than 1 kml coastal areas are protected as Environmental Conservation Areas or Special Coastal Management

PRESENT THREATS Areas, and many seagrass beds are located in the

Seagrasses in the Republic of Korea have been severely protected areas. There are critical problems associated impacted by coastal eutrophication, land reclamation, with the management of estuaries and designated

aquaculture and fishing activities, and these threats protected areas. There is no long-term management

still exist. Estuaries and coastal ecosystems in the plan for effective management and protection of

Republic of Korea are receiving extraordinary amounts estuarine and coastal ecosystems in the Republic of

of nutrients as a consequence of anthropogenic Korea. Punishment for illegal activities in the protected loading, as well as through industrial pollutants. areas, such as illegal fishing activities or illegal

Nutrient over-enrichment and pollutant discharge dumping, is very weak, so protection of Korean coastal

widely affect estuarine and coastal ecosystems and ecosystems by the law is not effective. Additionally, damage seagrass habitats. On the west and south economic advantages are usually given priority over

coasts of the Korean peninsula land reclamation is a ecological conservation or environmental preservation.

major contributor to loss of seagrass habitats. Since Therefore, even protected areas can be developed or

1945, more than 62 km' of tidal flats have been reclaimed for industrial facilities in the Republic of reclaimed"". Reclamation of tidal flats caused loss of Korea based on economic considerations. adjacent seagrass beds, and many seagrass beds have

disappeared due to reclamation over the last decades. Many land reclamation projects, which did not consider AUTHORS

the ecological and economical values of tidal flats and Kun-Seop Lee and Sang Yong Lee, Department of Biology, Pusan

seagrass beds, are still being constructed by the National University, Pusan 609-735, Republic of Korea, Tel: +82 10151 510

Government of the Republic of Korea. Oyster and 2255. Fax: +82 10151 581 2962. E-mail: kleeiahyowon.cc.pusan.ac.l^r

REFERENCES 10 Huh SH, Kwak SN [19981. Feeding habits of juvenile Acanthopagrus

1 Chung YH, Choi HK [19851. Distributional abundance and standing schlegeli\n the eelgrass {Zostera manna] bed in Kwangyang Bay

crop of the hydrophytes in the estuary of the Nadong River Nature Korean Journal of Ichthyology ]0: 168-175 [in Korean!,

Conservation 49: 37-42 lin Koreanl. 11 Lee TW, Moon HT, Hwang HB, Huh SH, Kim DJ [20001, Seasonal

2 Shin H, Choi HK, Oh YS 119931. Taxonomic examination of Korean variation in species composition of fishes in the eelgrass beds in

seagrasses: Morphology and distribution of the genus Phyltospadix Angol Bay of the southern coast of Korea. Journal of the Korean

IZosleraceael. Korean Journal of Plant Taxononny 22: 189-199. Fisheries Society 22: 439-U7 lin Koreanl.

3 Shin H, Choi HK [19981. Taxonomy and distnbution of Zostera 12 Huh SH, An Y-R [19971. Seasonal variation of shrimp [Crustacea:

(Zosteraceael in eastern Asia, with special reference to Korea. Decapodal community in the eelgrass [Zostera manna] bed in

Aquatic Botany bO: i9-tli. Kwangyang Bay, Korea, Journal of the Korean Fishenes Society 20:

4 Lee SY [20011, A Study on the Ecological and Taxonomical 532-542 [in Koreanl,

Characteristics of Zostera [Zosteraceael in Korea. PhD thesis, 13 Huh SH, An Y-R (19981, Seasonal vanation of crab (Crustacea:

Hanyang University, Seoul, 165 pp [in Koreanl, Decapodal community in the eelgrass ]Zostera manna] bed m 5 Choi HK (20001. Aquatic Vascular Plants. Korea Research Institute Kwangyang Bay, Korea. Journal of the Korean Fishenes Society 2h.

of Bioscience and Biotechnology. 535-544 [in Koreanl.

6 Lee SY, Kv»on CJ, Choi CI (20001, Sediment characteristics from the 14 Yun SG, Huh SH, Kwak SN (19971. Species composition and

beds of Zostera manna and Z asiatica. Journal of Natural Science seasonal variations of benthic macrofauna in eelgrass, Zostera

& Technology, Hangyang University!: 25-29 (in Koreanl. manna, bed. Journal of the Korean Fisheries Soc/ety 30: 744-752.

7 Lee K-S, Lee SY [20011. Status and restoration of seagrass habitat 15 Huh SH, Kwak SN, Nam KW [19981. Seasonal variations of eelgrass

on the south coast of the Korean peninsula. Nature Conservation ]Zostera manna] and epiphytic algae in eelgrass beds in

116: 15-20 (in Koreanl, Kwangyang Bay Journal of the Korean Fisheries Soc/e(y31: 56-62

8 Huh SH [19861. Species composition and seasonal variations in (in Koreanl.

abundance of fishes in eelgrass meadows. Bulletin of the Korean 16 Koh C-H ledl (20011. The Korean Tidal Flat: Environment, Biology

Fisheries Society 19: 509-517 [in Koreanl. and Human. Seoul National University Press, Seoul.

9 Huh SH, Kwak SN [19971. Species composition and seasonal

variations of fishes in eelgrass [Zostera marina] bed in Kwangyang

Bay Korean Journal of Ichthyology'): 202-220 [in Koreanl. The Pacific coast of North America 199

19 The seagrasses of THE PACIFIC COAST OF NORTH AMERICA

S. WyUle-Echeverria

J.D. Ackerman

The region along the Pacific coast of North America In contrast, soft-bottom habitats in the subtidal extending from the Baja Peninsula in Mexico and intertidal zones and estuaries are more commonly

through Alaska includes a wide variety of associated with plants in the genus Zostera, which can ecosystems ranging from subtropical through in form large monotypic stands in the Northeast Pacific a northerly transect. Given the nature of the leading estuaries, and mixed stand populations of Zostera edge coast and the resultant paucity of large regions marina and Zostera japonica, and sometimes Ruppia where soft sediments can accumulate, one would maritima, in estuaries from southern British Columbia, expect a rather limited diversity of marine angiosperms Canada, to Coos Bay, Oregon"". Zostera marina or seagrasses. However, a reasonably large number of provides important habitat for migrating waterfowl, species exist in this region for a number of reasons, juvenile salmon, resident forage fish, invertebrates and related in part to the ability of members of the genus wading birds"', and Zostera japonica is commonly eaten

Phyllospadix to colonize rocky shores. Eight seagrass by resident and migratory waterfowl'"". Noteworthy is species are recognized: Halodule wnghtii, Ruppia the use of Zostera marina as substrate for the laying of maritima, Zostera marina, Zostera japonica, Zostera Pacific herring [Clupea harengus pallasi] ; the roe is asiatica, Phyllospadix scouieri, Phyllospadix serrulatus also used by humans'". and Phyllospadix torreyi' ''. Four of them. Zostera Whereas little is known about the primary marina, Phyllospadix scouieri, Phyllospadix serrulatus production rates for Zostera japonica, Zostera marina and Phyllospadix torreyi, have probably been growing in productivity can be quite high on an annual basis (84- the region since the Pliocene'"; one, Zostera japonica, 480 g carbon/m'/yearl and standing stocks may cover is a recent addition to the northeast Pacific flora, being many hectares of seafloor'" '". For example, the large introduced as a result of oyster enhancement populations at Izembek Lagoon, Alaska, United States programs'"; and little is known about the phyto- 1160 hal and Laguna Ojo de Liebre, Baja California, geographic history of the three other species [Zostera (Mexico (175 hal, which are the primary staging asiatica, Ruppia maritima and Halodule wrightii]. grounds for migratory waterfowl, may be the largest

In terms of ecosystems, members of the genus Zostera marina ecosystems in the world'"^"'. In Phyllospadix Ithe surfgrasses] dominate the rocky addition, pre-contact First Nations peoples recognized subtidal and intertidal zones, where their condensed Zostera marina and its ecosystems as valuable rhizomes allow them to colonize hard substrates. The cultural and food resources. In British Columbia a three species in the genus Phyllospadix [Phyllospadix number of First Nations people (Nuu-chah-nulth. serrulatus, Phyllospadix scouieri and Phyllospadix Haida and Kwakwaka'wakwJ ate fresh rhizomes and torreyi] are endemic to the Northeast Pacific'''. Both leaf bases or dried them into cakes for winter food"". Phyllospadix torreyi and Phyllospadix scouieri were Moreover, the Seri Indians living on the Gulf of widely used in the region by indigenous people before California in Sonora, Mexico, used the Zostera marina European contact'". For example the flowers of seeds to make flour"".

Phyllospadix torreyi were sucked for sweetness by Ruppia maritima grows in many of the brackish children of the Makah people who live on the Olympic water coastal lagoons from Alaska south to Mexico"'".

Peninsula of Washington state, and leaves of the same Interestingly, Ruppia maritima was recognized as a plant were woven into pouches by the coastal Chumash separate species (from Zostera marina] by the Seri in the Channel Islands of California. elders but was not used by them"".

1)4 WORLD ATLAS OF SEAGRASSES

The last two species, namely Zostera asiatica BIOGEOGRAPHY and Hatodute wrightii, have rarely been the focus of Zostera marina lor eelgrassl Is the dominant species In biogeographic Investigation within this region. terms of blomass and habitats on the Pacific coast of

Zostera asiatica was found recently at three sites North America, where it grows In:

In southern California'^' and, leaving aside some the shallow waters of the continental shelf; regional studies documenting the presence of the Gulf of California ISea of CortezI;

Halodule wrightii in the Gulf of California'", there are coastal lagoons such as San Quintin, Baja no studies that discuss the habitat value or California, Mexico, and Izembek Lagoon, Alaska"";

autecoiogy of these plants In the Northeast Pacific estuaries formed by tectonic processes like San region. Francisco Bay;

Case Study 19.1 THE LINK BETWEEN SEAGRASS AND MIGRATING BLACK BRANT ALONG THE PACIFIC FLYWAY

Black brant lor sea goose, Branta bernicta nigricans] left). In the fall, most of the population moves on a

forage on seagrass flats Iprlmarily Zostera marina] non-stop, three-day transoceanic flight to Zostera

from Alaska to Mexico. In late August, after raising marina and Ruppia maritima beds in Baja California

young in the Yukon-Kuskokwim Delta 161°N, 165°Wl, at Bahia San Quintin 130°N, 116°W; see photograph

flocks gather at Izembek Lagoon |55°N, 163°W1 to below right), Laguna Ojo de Liebre 127°N, 1 U°Wl

graze on one of the largest intertldal stands of and Laguna San Ignacio (26°N, 113°W).

Zostera marina in the world Isee photograph below Spring migration coincides with midday maximum low water events, which allow brant day-

light opportunities to graze on the extensive seagrass resources growing on the tide flats at

locations like Morro Bay and Humboldt Bay, California; South Slough and Yaqulna Bay, Oregon; Willapa Bay and Padllla Bay, Washington; and Boundary Bay, British Columbia, Canada. International conservation efforts by the United States, Canada and Mexico are under way at wintering and migration stopover sites along the

eastern Pacific Flyway to protect seagrass habitats

in coastal embayments and estuaries.

In collaboration with David Ward lUS Geological Survey, Anchorage!

and Dr Silvia Ibarra-Obando ICentro de Investigaciones Cientifica y de

Educacion Superior de Ensenada, Baja California, Mexico).

Black brant grazing on the Zosters manna bed in Izembek Black brant on the Zostera manna and Ruppia mantima beds in

Lagoon, United States. Bahia San Quintin, Mexico.

•;# The Pacific coast of North America

coastal similar to Puget Sound. Washington™.

It is found along the coast of British Columbia \ including the coasts of Vancouver Island and Queen USA Charlotte Islands iHaida Gwaiil in sheltered bays and hembck ^X\/ '^ coves including Bamfield Harbour and Sooke Basin'". Laguun Alaska

The species also extends well into Alaskan waters to the Ik' Arctic Circle'"'. In the intertidal zone Zostera marina can co-mingle with Zostera japonica in the Pacific Northwest and Ruppia maritima in Baja California"'". Gulf of A I a V h a Whereas the majority of Zostera marina populations are perennial, annual populations (e.g.

Bahia Kino. Gulf of California. Mexico; Yaquina Bay.

Oregon. United States] in which 100 percent of the population are generative shoots that recruit from seeds each year have been reported"'". The appearance of branched reproductive shoots, a dimorphic expression quite distinct from the ribbon- shaped leaves of the vegetative shoots, begins to occur as water temperatures warm in the spring. In the

Pacific, visible in Northeast reproductive shoots are -Boundary Bay Olympic Peninsula- -.^ •:; February at southern sites such as Baja California. Willapu California; in late early Bin' , Mexico and southern March or • Puget Sound )ikjum(i Bit, April in Puget Sound, Washington; and as late as June in •' Coo.sBu\ northern sites like Izembek Lagoon. Alaska. Flowering Luiiiiiia Sail Ifpiatio , Oregon phenology is protogynous and the emergence of I'.lCll- IC OCEAN stigmas and then anthers effect the release, transport and capture of pollen, which rotate in the shear around stigmas"". is the Zostera marina monoecious; however Sun /•'ivnii.'ico Ba\- --^ lO-^ release of pollen and its stigmatic capture is separated Monterey 'ca|,f„n„a in time to promote an outcrossing breeding system'""'. ; MoiTO Bay In a region-wide analysis of population Channel Islands structure"". Alberto and colleagues found that: San Diego f there was high genetic diversity among Zostera

marina populations in the region; San Quintin • gene flow restriction existed for populations that were near each other; —' 30- Ltijiuna (}jo Jc Lk'hre intertidal plants in disturbed environments were -^ ' UiimbuUl Ben- , less diverse genetically than those in undisturbed Gulfof . -.^J^- Catifonm -- '. sites. 200 400 600 800 1000 Kilomelefs Baja California 120- W ^

In a subsequent study, focused on San Diego. Map 19.1

California, and Baja California. Mexico, Williams and The Pacific coast of North America Davis discovered that transplanted Zostera marina populations were less diverse genetically than naturally the early part of the 1900s'". At several sites from occurring populations'™'. southern British Columbia. Canada, to southern

Although Zostera japonica is typically smaller Oregon. Zostera japonica co-mingles with Zostera than Zostera marina, it can be confused with the marina (and occasionally Ruppia maritima''"] in the intertidal growing habit of Zostera marina Ivan intertidal region of many estuaries'". Zostera japonica typica]"". However Zostera japonica commonly grows is restricted in its northerly extent to the region near higher in the intertidal zone and has an open (as the city of Vancouver including Boundary Bay and opposed to tubular! leaf sheath characteristic of its Tsawwassen, where it is found primarily in the upper subgenus Zosteretla"''. It is a possible invader to the intertidal zones in muddy or silty areas'". Some region coming by way of the oyster trade with Japan in unconfirmed reports also exist of the species further

\|;' WORLD ATLAS OF SEAGRASSES

Case Study 19.2 THE LINK BETWEEN THE SEAGRASS ZOSTERA MARINA [T5 ATS'AYEM\ AND THE KWAKWAKA'WAKW NATION. VANCOUVER ISLAND, CANADA

Chief Adam Dick iKwaxsistala) and Kim Recalma-

Clutesi lOqwiloGwal are members of tfie Kwakwaka'wakw Nation on the northeast coast of Vancouver Island, British Columbia, Canada, Both

are keenly aware of the value of Zostera manna or

ts'ats'ayem from oral tradition of their nation.

They recall that at Grassy Point or wawasalth.

ts'ats'ayem is collected with a long thin pole or

k'elpawi thai is stuck into the substrate, rotated to

entwine the leaves of ts'ats'ayem, and pulled from

the bottom to reveal leaves, rhizomes and roots. On removal the plants are peeled exposing the tender

soft tissue of the leaf base. The leaves are then

wrapped around the rhizome, dipped in klina leulachon IThaieichthys pacificus] grease! and eaten as a ceremonial food. Whereas Grassy Point has both cultural and ecological value, Chief Dick, Kim Recalma-Clutesi

and others of the Kwakwaka'wakw Nation have concern about regional and global practices that

threaten the survival of ts'ats'ayem.

Chief Adam Dick twisting the seagrass IZos(era manna] for

dipping in eulachon [Tbaleiclitliys paaficus] grease. Plants were In collaboration with Chief Adam Dick and Kim Recalma-Clutesi

harvested at Deep Bay on the east coast of Vancouver Island on |Kwakwaka'wal

28 July 2002. Victoria, Victona, Canada!.

north in the Strait of Georgia'". Large stands are and Phillips and Menez'"' describe the habitat and

present in Boundary Bay. southern British Columbia, regional distribution of the three species. Phyilospadix

Canada, and Padilla Bay and Willapa Bay, serrulatus grovjs in the upper intertidal zone 1+1.5 m to Washington""'. The sediments and fauna within Zostera mean lower low water! on the outer coasts of Alaska,

japonica beds were found to be largely similar to those British Columbia, Washington and Oregon. Its

found in Zostera marina beds in Oregon, although distribution is often confused with Phyilospadix

some differences in sediment grain size and organic scouleri, which inhabits the lower intertidal and shallow

constituents were observed'"'. Zostera japonica has subtidal zone. It can be locally quite common, as on

been shown to be important to resident and migratory Graham Island (Haida Gwaii!"', and has a distribution

waterfowl in Boundary Bay""', and is used as habitat by that extends from southeast Alaska to Baja California,

epibenthic crustaceans in Padilla Bay. To the best of our although it is reported to be more abundant north of knowledge, there are no other studies linking Zostera Monterey, California" ". Phyilospadix torreyi grows at

japonica to secondary consumers either as a food or greater depths and is generally more abundant on the

habitat in North America. exposed parts of the coast and even in tidal pools with

The three species of the genus Phyilospadix are sandy bottoms, which are typically devoid of the other

found on exposed rocky coasts in the and in two Phyilospadix species. The distribution of

tide pools in the intertidal zone where their condensed Phyilospadix torreyi nearly overlaps Phyilospadix

rhizome allows them to attach to hard substrates. Three scouleri, but it is more abundant south of Monterey,

of the five species in this North Pacific genus are found California. The lack of information on its distribution

on the west coast of North America. Turner and Lucas'^^' may be related to the difficulty of making collections in

.:// The Pacific coast of North America 203

energetic habitats where Phytlospadix torreyi is found . mantima occur in coastal lagoons and estuaries

Whereas little Is known about the biogeography of these throughout British Columbia Including the Haida species, studies have revealed aspects of their Gwaii'"'. Further south Ruppia maritima occurs at many autecology and life history such as the adaptations of sites influenced by saline water in Washington, Oregon, seeds and roots to cling to surfaces in the rocky California and northern tvjexico" '". The leaves, intertldal zone'"'^ '"'. Phytlospadix spp. form patches of rhizomes and seeds of this plant are eaten by resident various sizes In the surf zones, except Phyllospadix and migratory waterfowl. serrulatus. which is often found in more protected l-ialodule wrightii is a subtropical species that environments'''. Plants In the genus Phytlospadix are occurs In the Gulf of California off the coast of largely clonal, and can be of a single sex due to the mainland Mexico" ', and Zostera asiatica is known to dioecious nature of the genus In this region. occur in three subtldal regions in central California,

Few studies have documented the habitat value of United States, where It forms underwater forests

Phyllospadix; however. Infaunal polychaetes are known ca 3 m tall'". More work Is necessary to elucidate the to live In the rhizome mats of Phyllospadix scouleri and life history traits and habitat value of these species in

Phyllospadix torreyi. Surfgrass wrack, identified as this region.

Phyllospadix torreyi. has also been found in the macrophyte detritus layers In submarine canyons, in HISTORICAL PERSPECTIVES southern and central California'"'. This decomposing Potential changes In the standing crop and areal vegetation provides food and habitat for deep-sea extent of Zostera marina have concerned natural benthic fauna''^'. In terms of commercially important resource managers in the Northeast Pacific for more species, researchers In southern California found that than two decades" "'. This concern Is primarily a in their larval pelagic stage, spiny . Panutirus function of the habitat value provided by the large interruptus, were attracted to experimental treatments ecosystems created by these plants. Changes In the containing Phytlospadix torreyi. distribution of Zostera japonica have received less

Ruppia mantima is a variable plant with a number attention. This species is an exotic but provides of named varieties with characteristic features, and is valuable waterfowl habitat'"". Given this, and the fact found in both freshwater and marine habitats. Ruppia that Zostera japonica has not yet been shown to maritima var spiralis occurs along the southern coast negatively Impact the indigenous Zostera marina, of Alaska Including the Alaska Peninsula, In British prompts some to argue for detailed resource

Columbia and in California'". Varieties longipes and inventories. Information about changes in the local or

Case Study 19.3 THE LINK BETWEEN SEAGRASSES AND HUMANS IN PICNIC COVE, SHAW ISLAND, WASHINGTON, UNITED STATES

Picnic Cove is a sheltered embayment on the

southeast corner of Shaw Island, which is centrally

located in the San Juan Archipelago in the Pacific Northwest (see photograph; i8°35N 122°57W|.

It contains a Zostera marina meadow of

ca 0.05 km^ '^^' and a very small patch of Zostera

japonica. in addition to multi-layered shell middens on the low bank at the head of the cove, which Indicate historical use by coastal Salish people.

After European contact, Picnic Cove became a favorite picnic spot.

It Is now the site of a long-term monitoring

station for Washington State Department of Natural

Resources' Submerged Vegetation Monitoring The San Juan Archipelago with

Project, and Is the location of quadrat-based insert of Picnic Cove on Shaw

investigations by S. Wyllie-Echeverria, University of Island, Washington, United

Washington. States. 204 WORLD ATLAS OF SEAGRASSES

However, there is anecdotal information to suggest that

Table 19.1 losses of Zostera marina have occurred in the two

Zostera marina and Zostera japonica basal area cover in the largest estuaries on the west coast of the continental

Northeast Pacific United States - Puget Sound and San Francisco Bay'"' - and we suspect losses have occurred at other sites as

Country Region Area Ikm'l well. Widespread efforts to monitor and map this

USA Port Clarence, AK''»"' 4.2 species in this region should help to determine if local

USA Safety Lagoon. AK''»"' 9.1 and regional losses continue in the 21st century, fvlore

USA lzembel( Lagoon, AK'^°' 159.5 effort IS needed to develop a programmatic response "' USA Kinzarof Lagoon, AK"°' 8.7 for comprehensive resource inventories of the other

USA East Prince William Sound, AK"' i.i seven seagrass species"". 4' Canada Roberts Bank, BC"^' 56" Canada Boundary Bay, BC'"" SEAGRASS COVERAGE

USA Puget Sound, WA''" 200 Whereas an estimate of the seagrass cover is

Sites within Puget Sound, WA marginally possible for Zostera manna, it is not

Padilla Bay'"' 32' possible for the other seven species. The conservative

King County'^^' 2 estimate for Zostera marina is approximately 1 000 km'

USA Grays Harbor, WA'°' 47.3 and is based on studies cited in Table 19.1 and our

USA Willapa Bay, WA'"' 159' personal knowledge of sites not yet mapped.

USA Netarts Bay, OR'"' 3.4

USA Yaquina Bay, OR"" 0.9" THREATS

USA TiUamool( Bay OR"" 3.6 The following discussion of the present and potential

USA Coos Bay, OR'" o.or threats to seagrasses is based on some information

USA Humboldt Bay, CA'"" 12.2 documented by Phillips"", Wyllie-Echeverria and

USA Tomales Bay"" 3.9 Thorn''" and studies therein, as well as a degree of

USA San Francisco Bay'"' 1.9 unpublished observation and conjecture.

USA San Diego Bay'"' 4.4 Coastal modifications and overwater structures in

Mexico Bahia San Quintin'™' 20 the form of ferry terminals, commercial docks, and

Mexico Laguna Ojo de Liebre'^"' 175 smaller residential docks and floats threaten the

Mexico Laguna San Ignacio""' 53 survival of species that could be shaded in either soft- bottom or rocky littoral zones. Shoreline armoring,

* Note: Includes both Zostera manna and Zostera japonica. which can alter the trajectory of reflected wave energy, may also displace seagrasses. The direct removal of

Source: Various sources - see individual references by regions. seagrasses through maintenance dredging is a rare

occurrence in the Northeast Pacific, but resuspension

of sediment associated with activity outside the

regional abundance of the other seagrass species in seagrass zone may reduce transmission of light and/or the Northeast Pacific remains largely unknown'"'. bury plant populations. The deposition of upland soils Direct use of seagrasses by humans for food, into the littoral zone as a result of industrial, com-

technology and medicine in the Northeast Pacific was mercial and residential development may smother

widespread before European contact"'"". However, and/or kill seagrass. Moreover, modifications to the

use now is quite localized and involves the weaving of coastline projection may alter longshore current

Phytlospadix spp. as a decorative element in small patterns resulting in changes to water clarity. personal baskets and the collection of Zostera marina Recreational watercraft (powerboats, jet skis,

plants for green mulch or the protection of culturally etc. I may scar seagrasses in soft-bottom environments

significant sites Isee Case Study 19.21. The United resulting in the fragmentation of populations and the States Department of Agriculture investigated the subsequent loss of wildlife habitat. Whereas larger

potential use of Zostera marina as a cultivar in coastal vessels (ferries, freighters, tankers, etc. I rarely venture desert ecosystems during the 1980s, but we are into shallow waters, accelerated currents associated

unaware of any projects to further this goal. with propeller wash connected with landing and getting

It is difficult to ascertain the extent of seagrass under way may displace seagrasses and affect current

losses due to coastal development and population flow during pollen and seed release. The swing of expansion since the beginning of the 20th century, as anchor chains, and chains and lines connected to no baseline data exist prior to the onset of these permanent buoys, can uproot plants and leave

changes. Any attempt to do so would be conjecture. permanent scars in populations.

v;

;:/ The Pacific coast of North America 205

Rack and rope culture techniques used in commercial s^lellfisl^ culture may sliade the bottom and alter nutrient regimes and current flow, which may result in the loss of seagrass cover in localized areas. Human trampling associated with the harvest of market-sized oysters from stakes used to set and grow oyster spat can also result in reductions in seagrass cover. Moreover, recreational clam removal using shovels can destroy meters of seagrass cover.

Spills associated with oil production from offshore oil platforms such as those located on the continental shelf of southern California or the transport by oceanic tankers from Alaska to southern ports in Washington and California may result in the death of seagrasses in the littoral zone depending on the intensity and duration of the spill. Proposals for Small net bag or flexible basket woven from the leaves of

offshore oil development in Canada, the United States PhyUospadix torreyi . found at Santa Rosa Island, California, and and Mexico are most problematic in this regard. dated 1 1 00- 1 500 in the Common Era.

Episodic events such as ENSO (El Nino Southern Oscillation] and interdecadinal variation have the potential to alter ocean temperature and rainfall regimes, which may affect local populations and may also operate on the regional scale. However, a preliminary investigation in Puget Sound found that both biomass and productivity of a subtidal Zostera marina population increased during an El Nino year (1991-921 demonstrating the need for time-series data collection to evaluate the status and trend of seagrass ecosystems. Subduction associated with the nearshore plate tectonic activity may alter the shape and size of the littoral zone, reducing or eliminating the seagrass cover, as in the case of the 196^ Alaska earthquake.

The fragmentation of populations caused by natural or anthropogenic disturbance can also provide habitat for introduced species such as the mussel,

Musculista senhousia, which can in turn prevent regrowth into fragmented areas, potentially leading to a more widespread decline in seagrass cover.

POLICY OPTIONS AND SEAGRASS PROTECTION

It is not clear that federal, provincial or state, or local Zostera marina prairie adjacent to the ferry terminal on Whidbey administrative laws and ordinances recognize the Island in central Puget Sound. Praine density is influenced by both eight seagrass species in the Northeast Pacific. the overwater structure and ferry propwash.

However, in the United States, Canada and Mexico, protection is afforded to Zostera manna because the ecosystems provided by this plant are valuable habitat AUTHORS for commercially and recreationally important species Sandy Wyllie-Echeverria, School of Marine Affairs, Box 355685, such as Pacific salmon [Oncorhynchus spp.l. Pacific University of Washington, Seattle, WA, USA, 98105-6715. herring [Clupea harengus pallasi] and black brant Tel: +1 360 468 4619; 293 0939. Fax: +1 206 543 1417. E-mail:

[Branta bernicla nigricans]"". In Washington state, zmseedOu.washington.edu

Zostera japonica is also protected, but to the best of our knowledge no other seagrasses are protected by Josef Daniel Ackerman, Physical Ecology Laboratory, University of administrative code in the Northeast Pacific. Northern Bntish Columbia, Prince George, BC, Canada, V2N 4Z9. 1

206 WORLD ATLAS OF SEAGRASSES

REFERENCES mtertidal Phyllospadix scouleri and Phyllospadix torreyi in Baja California (Mexico!. Marine Ecology Progress Series 173: 13-23. 1 Aguilar-Rosas R, Lopez-Ruelas J 119851. Ha/odule wnghti/ Aschers, enrichment macrophyte IPotamogetonales; Cymodoceael in Topolobampo Sinaloa, Mexico. 25 Velter EW, Dayton PK [19991. Organic by patterns of megafaunal populations in Cienc/as Mannas 11 121: 87-91. detritus and abundance Progress Senes 186: 137-148. 2 Phillips RC, Menez EG 119881. Seagrasses. Smithsonian submarine canyons. Marine Ecology [1994]. Managing Seagrass Systems Contributions to the Marine Sciences No. 34. 26 Wyllie-Echeverria S, Thom RM Needs. Alaska Sea 3 Phillips RC, Wyllie-Echeverna S [19901. Zostera asiatica Miki on the in Western North America: Research Gaps and 94-01. Pacific Coast of North America. Pac/ftc Science 44121: 130-134. Grant Program Report No. JR. S. Alberte RS. 4 Brayshaw TC [20001. Pondweeds. Bur-reeds and their Relatives of 27 Zimmerman RC, Reguzzoni Wyllie-Echeverria suitability for British Columbia. Royal British Columbia Museum, Victoria. 250 pp. Josselyn MN [1991]. Assessment of environmental of Zostera marina in San Francisco Bay. Aquatic Botany 39: 5 Damning DP [1 9761. An ecological model for late Tertiary growth

sirenian evolution in the North Pacific Ocean. Systematic Zoology 353-366. 25:352-362. 28 McRoy CP [19701. Standing stocks and other features of eelgrass coast of Alaska. Journal of the 6 Harrison PG, Bigley RE [19821. The recent introduction of the [Zostera manna] populations on the seagrass Zostera japomca Aschers. and Graebn. to the Pacific Fisheries Board of Canada 21: 1811-1821.

in North Puget Coast of North America. Canadian Journal of Fisheries and Aquatic 29 Bulthuis DA [1995]. Distribution of seagrasses a

Sc/ences 39: 1642-1648. Sound estuary: Padilla Bay, Washington, USA. Aquatic Botany 50:

7 Wyllie-Echeverria S, Cox PA [20001. Cultural saliency as a tool for 99-105. seagrass conservation. Biologia Marina Mediterranealll]-. 421-424. 30 Ward DH. Tibbitts TL, Morton A, Carrera-Gonzeles E, Kempka R [in

8 Phillips RC [19841. The Ecology of Eelgrass Meadows in the Pacific press]. Use of airborne remote sensing techniques to assess Mexico. Northviiest: A Community Profile, FWS/OBS-84/24. seagrass distribution m Bahia San Quintin, Ba|a California.

9 Rumrill S [2001]. South Slough National Estuanne Research Ciencias Marinas. Reserve, Charleston, OR ISSNERRI. Personal communication 31 McRoy CP, Bridges KW 119981. Eelgrass Survey of Eastern Prince

10 Baldwin JR, Loworn JR [19941. Expansion of seagrass habitat by William Sound- Report to the US Army Corps of Engineers.

the exotic Zostera japomca, and its use by dabbling ducks and Anchorage, Alaska. expansion and experimental brant in Boundary Bay, British Columbia Marine Ecology Progress 32 Harrison PG [1987]. Natural and the Senes 103: 119-127, manipulation of seagrass IZosfera spp 1 abundance response of infaunal invertebrates. Estuanne Coastal and Shelf 1 Ibarra-Obando SE, Boudouresgue CF, Roux M (1997]. Leaf

dynamics and production of a Zostera marina bed near its southern Science 24: 799-812. A, Turner T distributional limit. Aquatic 8o(any 58121: 99-112. 33 Norris JG. Wyllie-Echeverna S. Mumford T, Bailey subtidal seagrass 12 Ward DH, Markon CJ, Douglas DC [1997], Distribution and stability of (19971. Estimating basal area coverage of beds videography. Botany 58: 269-287. eelgrass beds at Izembek Lagoon, Alaska. Aquatic Botany 58: 229-240. using underwater Aquatic

13 Kuhnlem HV, Turner NJ 11991]. Traditional Plant Foods of Canadian 34 Submerged Vegetation Monitoring Project [20031, Nearshore indigenous Peoples: Nutrition, Botany and Use. Gordon and Breach Habitat Program. Washington State Department of Natural Science Publishers, Philadelphia. Resources, Olympia. Washington.

14 Felger RS, Moser MB [1985]. People of the Desert and Sea: Ethno- 35 Woodruff DL. Farley PJ. Borde AB. Southard JS, Thom RM [20011.

botany of the Sen indians. University of Arizona Press, Tucson, AR. King County Nearshore Habitat Mapping Data Report: Picnic Point of Natural 15 McRoy CP [19681. The distribution and biogeography of Zostera to Shilsole Marina. Report to King County Department

manna [eelgrass] in Alaska. Pacific Science 22: 507-513. Resources. King County. Washington. Matthew Van Ess, 16 Meling-Lopez AE, Ibarra-Obando SE [19991. Annual life cycles of 36 C-CAP Coastal Change Analysis Program [19951. Taskforce [CREST], 750 two Zostera marina L. populations in the Gulf of California: Director Columbia River Estuary Study

9710 Itel: 503 325 04351. Contrasts in seasonality and reproductive effort. Aquatic Botany Commercial Street, Room 205 Astoria, OR 6511-41:59-69. 37 Kentula ME. Mclnlire CD [1986]. The autecology and production Oregon, 17 Ackerman JD [2000]. Abiotic pollen and pollination: Ecological, dynamics of eelgrass IZosfera manna L.I in Netarts Bay,

functional, and evolutionary perspectives. Plant Systematics and fsfuanes 9131: 188-199.

Evolution 222: 167-185. 38 Clinton PJ. Young DP, Specht DT (20021. A hybrid high-resolution

distribution in 18 Ruckelshaus MH [1995] Estimates of outcrossing rates and of image classification method for mapping eelgrass for inbreeding depression in a population of the marine angiosperm Yaguina Bay. Oregon. [Submitted to 7th ERIM Conference

Zostera marina. Marine Siofogy 123131: 583-593. Remote Sensing in Marine and Coastal Environments, Miami,

19 Alberte RS, Suba, GK, Procaccini G, Zimmerman RC, Fain SR Florida, 20-22 May 2002.1 www.veridian.com/conferences

[1994]. Assessment of genetic diversity of seagrass populations 39 Strittholt JR. Frost PA (19961. Determining Abundance and

using DNA fingerprinting: Implications for population stability. Distribution of Eelgrass IZosfera spp.l in the Tillamook Bay

Proceedings of the National Academy of Sciencesti: 1049-1053. Estuary. Oregon Using Multispectral Airborne Imagery,

20 Williams SL, Davis CA [1996]. Population genetic analyses of vwi/w.cwrc.org/html/reportse-h.htm transplanted eelgrass IZoslera manna] beds reveal reduced genetic 40 Harding LW Jr. Butler JH [19791. The standing stock and production California. California diversity in southern California. Restoration Ecology li\2\: 163-180. of eelgrass, Zostera manna, in Humboldt Bay,

21 BackmanTWH [1991]. Phenotypic and genolypic variability of Fish and Game 65131: 151-158.

Zostera marina on the west coast of North America. Canadian 41 Spratt JD [19891. The distribution and density of eelgrass Zostera

Journal ofSotany 69: 1361-1371. manna in Tomales Bay, California. California Fish and Game 7514|:

22 Posey MH [1988]. Community changes associated with the spread of 204-212. an introduced seagrass, Zostera japonica. Ecology bW: 974-983. 42 Wyllie-Echeverna S (19901. Distnbution and geographic range of

23 Turner T, Lucas J [19851. Differences and similarities in the Zostera manna eelgrass in San Francisco Bay. In: Merkel KW,

community roles of three rocky mtertidal surfgrasses. Journal of Hoffman RS (edsl Proceedings of the California Eelgrass Experimental Marine Biology and Ecology 8912-31: 175-189. Symposium. Sweetwater River Press. National City. CA. pp 65-69.

24 Ramirez-Garcia P, Lot A, Duarte CM, Terrados J, Agawin NSR 43 US Navy [20001. Eelgrass Survey 5WDIV Naval Facilities

11998]. Bathymetric distribution, biomass and growth dynamics of Engineering Command. Port of San Diego. San Diego Bay. The western North Atlantic 207

20 The seagrasses of THE WESTERN NORTH ATLANTIC

F.T. Short

C.A. Short

Eelgrass [Zostera marina] Is the overwhelmingly dramatic declines in eelgrass populations have been dominant seagrass in coastal and estuarine areas documented"^''". Despite some laws that recognize the

of the western North Atlantic, a region considered habitat value of eelgrass, there is no direct protection of

here as the Atlantic coast from Quebec (Canada! at seagrasses in Canada or the United States.

approximately 60°N to New Jersey (United States) at In Canada, eelgrass is found on the east coast

39°N" ". Eelgrass meadows provide a wide array of south of the Arctic Circle, where it occupies vast inter-

ecological functions important for maintaining healthy tidal and subtidal areas. Eelgrass is found in Hudson

estuarine and coastal ecosystems'", creating essential Bay, in the harbors of 's rocky shoreline

habitat and forming a basis of primary production that and in large meadows in the Northumberland Strait off supports ecologically and economically important Prince Edward Island. Eelgrass beds circumscribe much

species in the region""". The importance of eelgrass to of Nova Scotia, though absent from the northern coast-

estuarine and coastal productivity was highlighted in the line of the .

1930s, when a large-scale die-off of eelgrass occurred In Ivlaine, the northernmost US state on the east

on both sides of the Atlantic due to wasting disease"'. coast, extensive eelgrass beds occupy the full range of

The wasting disease has since been shown to be caused eelgrass habitat conditions. In northern Maine, with the

by a pathogenic slime mold, Labynnthula zosterae'" and highest tidal ranges in the world Imore than 8 ml,

has been reported in several species of Zostera''"". The eelgrass occurs mostly in protected bays and harbors, as

disease resulted in the loss of over 90 percent of the well as tidal rivers. In mid-coast Maine, eelgrass is also

North Atlantic eelgrass population, and this loss had a found on exposed coasts and around islands, for

catastrophic effect on estuarine productivity including instance in Penobscot and Casco Bays. Eelgrass

the disappearance of the scallop [Argopecten irradians] distribution in southern Maine ranges from sheltered

fishery and drastic reduction in brant [Branta bernicla] areas to exposed coasts, but eelgrass occurs less

populations"". After 30-40 years, eelgrass largely frequently, due to the coastal geomorphology which is

recovered from the 1930s' wasting disease, although in dominated by salt marshes; widgeon grass is found in

some areas it has not regained its previous distribution'''. many salt marsh ponds and tidepools.

A second seagrass found in the region is widgeon New Hampshire, south of Maine, has a coastline

grass [Ruppia maritima]; it occurs sporadically, mainly of only 27 km, and a drowned river valley estuary

in low-salinity, brackish and freshwater areas, marsh consisting of the Piscataqua River and Great and Little

pools and some tidal rivers. Relatively little is known Bays"". Eelgrass meadows occur at the mouth of the

about the distribution and ecology of widgeon grass; in river in Portsmouth Harbor (see Case Study 20.1), both

most areas it is much less common than eelgrass. intertidally and to a depth of 1 2 m below mean sea level,

Throughout the western North Atlantic region, in small patches along the sides of the deeper river

large meadows of eelgrass are found from Canada channels, sparsely in Little Bay and in a large

through New Jersey. Despite fluctuations in some areas monospecific expanse within Great Bay Along the rest

due to recent episodes of wasting disease and recovery, of the New Hampshire coastline, eelgrass is found in

the trend over the past 30 years has been a steady deep meadows along the exposed coast and in smaller

decrease in eelgrass distribution and abundance due to patches in sheltered areas and harbors. Widgeon grass

anthropogenic impacts. In the few areas of this region occurs in salt marsh ponds and, to a limited extent, in where habitat change analysis has been carried out, upper Great Bay"^'". Further south, the state of 208 WORLD ATLAS OF SEAGRASSES

Massachusetts has extensive eelgrass meadows in the Vineyard Sound, eelgrass is disappearing due to physically protected areas of Cape Cod, the offshore anthropogenic impacts"*'. No known intertidal eelgrass

islands and along its glacially striated southern occurs in Massachusetts or further south. Widgeon

shoreline. In Boston Harbor, north of Cape Cod. grass occurs in some salt marshes and brackish ponds.

eelgrass beds are slowly recovering due to improved Rhode Island is the smallest state in the United water clarity from installation of an offshore sewage States, with a long shoreline for its size. Heavily develop-

discharge. South of Cape Cod. in Buzzards Bay and ed Narragansett Bay. a water body dominating the state.

Case Study 20.1 PORTSMOUTH HARBOR, NEW HAMPSHIRE AND MAINE

The western North Atlantic exhibits a range of impacts, eelgrass forms a lush green expanse only environmental conditions supporting eelgrass. from rarely disturbed by lobster pots or fishing activity

pristine to highly developed and from intertidal to The mix of habitats in which eelgrass grows in

deep subtidal. Cold winters produce conditions of ice Portsmouth Harbor is representative of many of the scour while summer heat can desiccate intertidal eelgrass habitats found throughout the western eelgrass. Portsmouth Harbor, the mouth of the North Atlantic. North of Portsmouth Harbor, in Great Bay Estuary on the border of Maine and New Maine and Canada, eelgrass may grow in vast inter-

Hampshire, typifies many of these conditions. Within tidal meadows in areas of extreme tidal fluctuation.

the harbor, eelgrass flourishes in large intertidal South of Portsmouth Harbor, eelgrass is rarely found

flats, often exposed for several hours around low intertidally, but often forms shallow meadows in

tide and, at high tide, submerged by over 3 m of back barrier lagoons or salt ponds. However, the

water Eelgrass plants on these flats are small and eelgrass habitats in Portsmouth Harbor capture

thin bladed, typically with leaves less than 30 cm many of the conditions affecting its distribution

long. Across the channel in water about 3 m mean throughout the western North Atlantic, including

sea level, exceptionally long-leaved (2 ml eelgrass large tidal variation, temperature extremes, ice, both

grows in a protected area behind a US Coast Guard significant human impacts and restoration efforts,

pier; the bed is subject to frequent boat activity and and ongoing wasting disease episodes. mooring impacts. Upstream from the Coast Guard station in the ^ 1.96 km' highly commercial harbor, eelgrass developed some NEW thrives despite the nearby sewage discharge for the HAMPSHIRE

city of Portsmouth, because high tidal volumes t

. ; OULFOF deliver clear ocean water However, adjacent to these V *M/N£ .. 1 beds, dredge spoil illegally dumped in a shallow MASSACHU^fm subtidal zone buries former eelgrass habitat, while ^ 3.0 1.5W0 1.5 3.0 4.5 11 across the channel the hardened shoreline of the Above sea level Below sea level

Portsmouth Naval Shipyard has virtually eliminated utile , MAINE eelgrass and the possibility of its recovery. In less Boy V. . % heavily developed areas upstream in the Piscataqua Great Boy V River eelgrass has been transplanted as mitigation . NEW HAMPSHIRE

for port expansion, replacing beds lost in the early

1980s to an outbreak of wasting disease'"'. Some of

the transplants expanded into beds which continue to ^ 1996 ";,;,-? ,«•<:- Portsmouth thrive eight years after transplanting; others died 1000 iaX]2GG0Meten '' .y^f.r, Harbor soon after transplanting due primarily to biotur-

bation'^". Further up-estuary, the Piscataqua River Eelgrass distribution by depth in Portsmouth Harbor, Great Bay

connects to Little Bay and then Great Bay with its Estuary, on the border of New Hampshire and Maine, United States.

extensive intertidal eelgrass meadows. Notes: Depths plotted as mean low water, with an average tidal range At the mouth of Portsmouth Harbor and along of 2 7 meters Data from 1996; eelgrass polygons were determined the open New Hampshire coast, eelgrass beds thrive from image analysis and ground-truthing of aenal photography using in the clear waters to a depth of 12 m the C-CAP protocol'"'. USCG United States Coast Guard station; PNS mean sea level. Here, at depths below most human Portsmouth Naval Shipyard, N

The western North Atlantic 209

has only a few remaining small eelgrass beds. More extensive eelgrass occurs in sheltered coastal ponds be- hind barrier beaches on the south shore of Rhode Island but losses are occurring (see Case Study 20.21. Widgeon grass is found in the salt ponds in areas of groundwater intrusion and in some freshwater ponds. Connecticut, on

Long Island Sound, has eelgrass in subtidal habitats of some protected bays, with offshore beds in the shelter of

Fishers Island. All eelgrass beds in Connecticut occur in the eastern third of the coastline due to poor water quality in the western part of Long Island Sound.

Widgeon grass occurs in some salt marshes. New York State has eelgrass only around Long Island with no known beds on the north shore of the island, but iiulloj Sl.Lmrrmr V>—'^^^tl substantial meadows in some bays and inlets of the east St Lawrence River X^Vnrxe HdwanJ Island ' Newwew _v j: south shores, including the Peconic Estuary. Brunswick *- and \y ^ /P> Bav ofFundv ' "^^^""'^^ NortiuimherUmJ is in the '\ •^' Siraii Widgeon grass found upper brackish portions of ' j^ Mt y \ ^ .•'^ ' Nova some bays and salt marshes. New Jersey, the . Penobscot Sin'^^^^^ V S*' Ma^milBay—^^ >,y' ^°"^ southernmost state in the region, has extensive eelgrass Baiton Htirbor~~^.^ , ^„ . i n i. —< Forlstmnitlt Iwrhvr beds in the southern bays with Barnegat Bay having the ^ 'T "4>i>- Cape Cod

'\ best-documented populations. In New Jersey, eelgrass . k" \ Wiiifuail Buy "' ~ 40- \ Sarrufianscll Bin' - 'ATLANTIC is predominantly found in shallow, open lagoons, while \ Niiti^ni P1U1J LiHi^ hluikl Sounil OCEAN widgeon grass occurs in brackish water areas. 'A^ ji i Bamixol Bay Within the western North Atlantic region, eelgrass if 200 400 600 600 1000 Kiiomelere restoration has been undertaken sporadically; consider- able research has taken place on both transplanting and Map 20.1 seed planting. New transplanting methods have been The western Nortti Atlantic developed which simplify the transplanting process and increase its level of success; projects have transplanted low of 0.7 to a high of 19.1 g dry weight/mVday At the up to 2.62 hectares of eelgrass'^'. These relatively small southern end of its western North Atlantic range, and expensive projects also demonstrate that pres- eelgrass distribution is limited by high summer ervation of seagrass is vastly preferable to, and less temperatures, the relatively small tidal range, and the costly than, restoring lost habitat. generally low-organic, sandy sediments of the back lagoons. North of Cape Cod, eelgrass

BIOGEOGRAPHY grows most commonly in estuarine environments or

In the western North Atlantic, eelgrass is found in both along the open coast where the cooler water intertidal and subtidal areas, from a depth of +2 m to temperatures, higher tidal ranges, and fine-grained

-12 m mean sea level'^'. Depth distribution is limited by organic sediments create conditions that support water clarity and the large tidal range along the North larger plants and greater biomass.

Atlantic coastline. Eelgrass distribution ranges from Eelgrass in the western North Atlantic provides the protected low-salinity (5 psul waters of inner habitat for numerous commercially important fish estuaries and coastal ponds to high-energy locations and shellfish species"". Young winter flounder fully exposed to the Gulf of Maine and the North Atlantic [Pseudopleuronectes americanus] concentrate in with salinity of 36 psu. Eelgrass inhabits a range of eelgrass beds'"'"; juvenile lobsters [Homarus sediment conditions from soft, highly organic muds to americanus] likewise favor eelgrass habitat and have coarse sand and partial '^'. In a comparative study been shown to overwinter in burrows within eelgrass of eelgrass populations from Maine to North Carolina, beds""'"; Atlantic cod [Gadus morhua] is documented some general patterns of variation with latitude were as using eelgrass beds as nursery habitat in Canada"". found'*'. In summary, eelgrass shoot density decreases Other commercially and recreationally important

(1 275 to 339 shoots/m'') with increasing latitude (south species that use eelgrass habitat include smelt to north], while leaf biomass (from 106 to 249 g dry [Osmerus mordax], which spends time in eelgrass as weight/m^l and plant size (35 cm to 1 25 cm average leaf part of its migratory cycle"", and striped bass IMorone length! increase with increasing latitude'*'. Additionally, saxatilis] which have been tracked moving into eelgrass eelgrass leaf growth showed a significant increase beds to feed'"'. Shellfish, including bay scallops from south to north over this geographic range, from a [Argopecten irradians] and blue mussels [Mytilus V WORLD ATLAS OF SEAGRA5SES

edulis], have been shown to utilize eelgrass beds, and anthropogenic nutrient and sediment discharge all sometimes for settlement of juvenile phases and continue to impact eelgrass habitat and areas where it sometimes as adults'""'". could return. The loss of eelgrass has not been While some species associated with eelgrass guantified in the region but certainly differs in two areas

habitat are in decline, such as flounder, cod and of the coast. North of Cape Cod, Massachusetts, scallops, no species are officially designated as threat- eelgrass loss since settlement is estimated to be in the ened. The eelgrass limpet, Lottia atveus, became extinct order of 20 percent, while south of Cape Cod, which is

after the 1930s' wasting disease'"'. The brant goose more heavily populated and industrialized, we estimate {Branta bernicla], a species dependent on eelgrass as a that 65 percent of eelgrass distribution has been lost. primary food source, was abundant before the 1930s Two locations in New England have and has only partially recovered. Ducks, swans and documentation of the rapid decline of eelgrass other species of goose use eelgrass as food and are populations resulting from anthropogenic nutrient

known to stop in eelgrass areas during migration. loading by way of contaminated groundwater discharge: Waquoit Bay, Massachusetts, and NInlgret HISTORICAL PERSPECTIVES Pond, Rhode Island, In Waquoit Bay, the decline in

Major losses of eelgrass area in the western North eelgrass associated with nitrogen loading rates was Atlantic occurred before any documentation of documented In a space-for-time substitution of seven distribution was accomplished. Areas such as Boston sub-estuaries having varying degrees of housing Harbor IMassachusettsI and the Providence River development"". The greatest eelgrass loss occurred in (Rhode island] have experienced human modification the sub-estuaries with most development; overall, 60 and impact for the last 400 years; sites within these percent of the eelgrass was lost from this estuary in harbors which probably supported eelgrass are now five years. In Ninigret Pond, eelgrass distributions were historical and filled or degraded. Historical reports and anecdotal compared over a 32-year period using information from fishermen, as well as early navigation recent maps; areal distribution of eelgrass declined by

charts, all indicate that eelgrass extent was previously A] percent"" (see Case Study 20.21. Little Harbor and Barnegat much greater than it is today. For example, in In New Jersey's Egg Narragansett Bay, Rhode Island, S. Nixon has found Bay, eelgrass beds were mapped through the 1970s 1999'^". charts dating to the 1700s showing eelgrass well up and 1980s, and again In Throughout the period,

into the Providence River in the upper estuary. Today, 20 km' of eelgrass were lost. Little Egg Harbor and the the small amount of eelgrass in Narragansett Bay adjacent Barnegat Bay are the only two areas in New extends only two thirds of the way up the bay'™'. Jersey that still support eelgrass to any extent. Other

Quantitative studies of seagrass loss in the western areas in New Jersey which supported eelgrass

North Atlantic have occurred only in the past decade or historically have declined and show no recovery.

so, and in only a few locations. Maquolt Bay in Maine (northern Casco Bay! has The wasting disease of the 1930s almost been impacted by mussel dragging, a fishery practice in eliminated eelgrass from much of the area reported which a weighted steel frame and net are dragged here. This decline had major ecological impacts'". The through eelgrass beds to harvest blue mussels'"' (see human use of eelgrass wrack for insulation, bedding, Case Study 20.31. Dragging for mussels in 1999 created stuffing and as mulch, which constituted a commercial a 28.3-hectare bare area In the center of a large

effort in Canada and northern New England states, eelgrass meadow'"'.

dropped off during the 1930s and 19i40s and never Great Bay, New Hampshire, experienced a

revived''""'. Today only a few home gardeners collect recurrence of the wasting disease in the 1980s. eelgrass wrack for mulch, Eelgrass populations went from 824 hectares In 1986 to 130 hectares in 1989. This loss, accounting for 80 AN ESTIMATE OF HISTORICAL LOSSES percent of the eelgrass In Great Bay, was reversed by

Since the arrival of Europeans in the region, the western rapid recruitment from seed production and a recovery

North Atlantic has lost eelgrass populations in virtually of eelgrass to 1 015 hectares by 1996.

all areas of intense human settlement. Today, most of Changes In the physical environment that may these areas remain devoid of eelgrass although, with result from eelgrass loss Include seafloor subsidence improved sewage treatment and environmental controls and loss of fine particle sediments and organic

of discharge, some industrialized areas (Boston Harbor matter'"", increase In and and New Bedford Harbor, Massachusetts! are beginning decrease In sediment deposltlon'^^', and short-term to show eelgrass recovery or are now suitable for water quality degradation caused by resuspended "'. restoration. Dredging, filling, marina development, boat sediment'" Biological changes may Include a shift

activity, fishing practices, hardening of the shoreline In the benthic infauna from a predominantly The western North Atlantic

Case Study 20.2 NINIGRET POND, RHODE ISLAND

Loss of eelgrass is a problem in shallow nutrient- in shallow areas of the pond (see figures]. The major

enriched estuaries of the urban and urbanizing loss of eelgrass in the pond occurred in shallow

northeastern United States. From 1 960 to 1 992 there areas where macroalgae and groundwater enrich-

was a clear relationship between increased housing ment had the greatest impact; eelgrass in the

density and decreased eelgrass area in Ninigret deeper areas showed little change.

Pond, Rhode Island, a shallow estuanne embayment Maps of eelgrass distribution were compared

behind a barrier beach"^'. With increased housing with the number of houses in the watershed, and a

density, and corresponding increased nutrient significant linear trend of eelgrass area loss with loading via enriched groundwater which produced increased housing over time was demonstrated Isee

macroalgal blooms, eelgrass area in Ninigret Pond figure!"'". Over the 32-year period examined, housing

decreased rapidly between 197i and 1992, primarily in the watershed quadrupled, while eelgrass areal distribution declined 41 percent.

In shallow estuarine systems, such as Ninigret 1974 Pond, throughout the northeastern United States'", especially within watersheds dominated by highly permeable sand/gravel glacial outwash aquifers,

groundwater is a dominant source of freshwater and

associated nitrate contamination'"-^". There is minimal removal of nitrate as groundwater discharges from highly permeable and low-organic

soils into estuarine shorelines. In Ninigret Pond, groundwater entering the 4.54 km^ discharge pond was clearly visible in thermal infrared photographs,

ultimately contributing to eelgrass loss, mostly m

shallow areas and due to macroalgal smothering"".

Subsequently, eelgrass has continued to decline in ^1992 Ninigret Pond.

10.8 ^ 0.5W0 0,5 1.0 1.5 2.0

Above sea level Below sea level 6

s<0, 5 1960 ( SO.SMO 0.5 1,0 1,5 »>N 2,C X, Above sea level Below sea level • 1974 ^ 4 \

1980»^ 1 3 ^1992 tn -a S 2

500 500 1000 Metere 1992

500 1 000 1 500 2 000 2 500 3 000 Eelgrass distribution in Ninigret Pond, Rhode Island (United Houses in watershed States! plotted by depth for 1974 and 1992,

Change in eelgrass area in Ninigret Pond, Rhode Island

Notes: Data from image analysis of aerial photography and ground- (United States! plotted against increasing number of houses in trulhmg'"'. the watershed"".

deposit-feeding community to a suspension-feeding changes reduce estuarine productivity and can prevent community'" and a reduction in epifaunal species natural recolonization of eelgrass even when water abundance'"". These types of physical and biological quality becomes adequate. 212 WORLD ATLAS OF SEAGRASSES

20.11. The majority of eelgrass area occurs north of

Table 20.1 Cape Cod. There are no known areal estimates for

The area of eelgrass, Zostera marina, in the western North widgeon grass.

Atlantic Potential seagrass habitat is difficult to measure

because the depth distribution of eelgrass in most areas

Location Area [\^m'] Year Method of the northeastern United States varies depending on

Maine 128.10 1992-97 C-CAP water clarity. Methods have been developed for

NewHampshire 11.88 1996 C-CAP determining potential seagrass habitat''^', but have not

Massachusetts 158.9i 1995 C-CAP been comprehensively applied to the region.

Rhode Island 1999 and C-CAP ^^^ 1992 C-CAP A DESCRIPTION OF PRESENT THREATS

Connecticut 2.56 1993-95 Diver survey Over the last decade, eelgrass populations have

NewYorl( 8.50 1994 Ground declined in some parts of New England and elsewhere

(data for Peconic Estuary only! survey due to pollution associated with increased human

Nev« Jersey 60.83 1999 Aerial photo populations"'"' and episodic recurrences of the

Idata for Barnegat Bay and Little Egg Harbor onlyl wasting disease'""', as well as other human-induced

Total 374,37 1990s and natural disturbances"".

Seagrass is often impacted by direct damage

Notes: Year indicates the date of sampling, C-CAP is the US from boating activities such as actual cutting by

National Oceanic and Atmospheric Admmislralion's Coastal propellers, propeller wash and boat hulls dragging

Change Analysis Program, which includes a protocol for through vegetated bottom'"'"'. Other activities relating

assessing seagrass Irom aerial photography'"'. The estimated to boat operation and storage that impact eelgrass

area of eelgrass was obtained from comprehensive surveys include docks which can shade the tide flat and prohibit

within each location, except for Nevw York and New Jersey, light penetration"'™', moorings which create holes

where more cursory information was available. No quantitative within meadows from the swing of the anchor chain'^'".

data were available for Canada. and channel and marina dredging'^". Certain fishing and aquaculture practices also

Sources: Maine: S. Barl

Resources; New Hampshire: F.T Short, University of New trawling or dragging through Zostera marina meadows

Hampshire; Massachusetts: C. Costello, Massachusetts can eliminate areas of eelgrass or reduce shoot density

Department of Environmental Protection, Rhode Island: and plant biomass'"' (see Case Study 20.31. Clam

Narragansett Bay Esluary Program and Short et al'"': digging can disturb eelgrass either by direct removal or

Connecticut: R, Rczsa, Connecticut Department of increased turbidity.

Environmental Proleclion; New York- Peconic Estuary Program, The following threats to eelgrass in the western

NY, New Jersey: Center for Remote Sensing and Spatial North Atlantic are listed roughly in order of magnitude,

Analysis, Rutgers University and Lathrop et 3( "", except for the last three where the level of threat is

difficult to quantify. The impact of brown tide can be

severe in localized areas, occurs frequently in part ot

AN ESTIMATE OF PRESENT COVERAGE the region (Long Island! and is unknown in others"''".

Eelgrass in Canada was mapped in the early 1980s but The relative impacts to eelgrass health and distribution

never digitized. Tfie primary known areas of eelgrass from both climate change and sea-level rise are

distribution in are summarized here. presently unknown'"'. Wasting disease has the

There is eelgrass in , Quebec, part of Hudson potential for very great impact, as seen in the 1930s,

Bay'^". Extensive eelgrass meadows are reported in the but most recent outbreaks of the wasting disease have Northumberland Strait between New Brunswick and been followed by rapid recovery.

Prince Edward Island. Eelgrass beds are found in parts Point and non-point source nutrient loading:

of the St Lawrence River""'. In Nova Scotia, on the Anthropogenic inputs of nutrients from land

Atlantic coast, eelgrass grows in coves, tidepools and on development, sewage disposal, agriculture and the

the exposed coast"". There is probably more eelgrass in increase in impervious surfaces all contribute,

eastern Canada than in the US states of the western resulting in overenrichment which promotes algal

North Atlantic region combined, but no quantitative data blooms'^^'. In many places, nutrient-contaminated are available for Canada. groundwater discharge to bays and coastal ponds "'. in the United States, current distribution by is a major contributor to eelgrass loss"'

state ranges from 250 hectares in Connecticut to over Sediment runoff: Land disturbance and defor-

15000 hectares in neighboring Massachusetts (Table estation produce increased loads of sediment to The western North Atlantic 213

coastal waters, increasing turbidity and eelgrass, but eelgrass habitat may be given special

decreasing light levels. consideration in permit review processes.

Dredging: Despite laws regulating dredge and fill, There are no marine protected areas having

routine dredging is permitted in bays and harbors eelgrass in the western North Atlantic region. There are for channel maintenance, deepening of mooring five National Estuarine Research Reserve INERR) sites

fields, and Improved boat access. AU these activities often cause direct and indirect destruction of eelgrass. Case Study 20.3 Fisheries and shellfisheries harvest practices: MAQUOIT BAY, MAINE

Net dragging for fish and shellfish in parts of the

region can have severe local impacts, uprooting Maquoit Bay, Maine (United States! is the

eelgrass over large areas of the bottom. Dragging location of a vast eelgrass bed representing one

scars persist In eelgrass beds for many years. of the more extensive stands of Intertidal

Hardening of the shoreline: Creation of bulkheads seagrass In the western North Atlantic and sea walls, as well as elimination of shoreline The plants range from small, thm-bladed

vegetation, increase sediment input to coastal eelgrass with extensive flowering in the shallow waters and exacerbate sediment resuspension. intertidal to robust, densely growing large plants

Filling: Historically, filling had a large Impact on (more than 2 ml at the lower extent of the

eelgrass, but now regulations limit fill activity In intertidal. This estuary in mid-coast Maine has a

coastal waters. tidal range of 5 m, resulting in the twice daily Boating, Including boat docks and moorings: exposure of much of the eelgrass; subtidal beds

Boating activities In shallow waters resuspend extend to a depth of 10 m in the clear waters of

sediments and create propeller scars, damaging the outer bay The bay is harvested for wild blue eelgrass beds. Docks shade eelgrass to the point mussels [Mytilus edulis], soft-shell clams \Mya

of elimination and bed fragmentation. Moorings arenana] and clam worms [Nereis virens]

create holes in eelgrass beds as the long mooring Fishing practices include dragging for mussels,

chains, needed for the high tidal ranges In the which has destroyed up to 0,3 km^ of eelgrass in region, drag across the bottom. a season (see photographl. Such uprooted areas

Aquaculture pens and rafts: The rapid expansion in the eelgrass meadow are predicted to require

of Atlantic salmon aquaculture in Maine and 10-17 years to recover via a combination of seed

Canada has led to deployment of pens within recruitment and rhizome elongation'"'. In sheltered estuarlne areas. High nutrient loads contrast, the local practice of digging for clams

resulting from excess feed and fish waste create and clam worms with a shovel or rake results in

local eutrophlcatlon conditions. Blue mussel rafts partial disturbance to the inshore edge of the shade the bottom and promote macroalgal eelgrass meadow; the beds recover after two growth that causes eelgrass loss. years.

Brown tide: Algal blooms shade and eliminate eelgrass.

Climate change and sea-level rise: The potential

impacts of these changes are great'""'.

Wasting disease: Historically, the wasting disease severely Impacted eelgrass distribution;

currently, the disease Impacts populations at less

severe levels. The conditions that led to the

widespread disease outbreak of the 1 930s are not

known, but there Is the potential for recurrence.

POLICY

In Canada, seagrass receives no specific legal Maquoit Bay, Maine (United States!, sfiowing scars in the protection. In the United States, seagrass Is protected eelgrass bed caused by mussel dragging. under the Clean Water Act as a "special aquatic site" and falls within Essential Fish Habitat as a "habitat area Note: Below ttie scrape marks, the round areas ol disturbance of particular concern" under the Magnuson-Stevens to the bed are caused by the mussel draggers discharging Fishery Conservation and Management Act. Neither of debns from their nets as they return for another pass. these laws provides complete or direct protection of

:,X 214 WORLD ATLAS OF SEAGRASSES

permit in the mid-1990s based largely on its potential impact on eelgrass habitat. The US Army Corps of Engineers, the agency primarily responsible for dredge,

fill and other construction activities in coastal waters of the United States, has an increasing awareness of the

importance of eelgrass habitat, and has recently undertaken mitigation for some routine mooring area

dredge activities that impacted an eelgrass bed. Clearly,

more specific protection of seagrass habitat is needed in the western North Atlantic.

ACKNOWLEDGMENTS

Students sampling intertidal lostera manna at a SeagrassNet We thanl< the University of New Hampshire Agncultural Expenment Station

monitoring site in Portsmouth Harbor, New Hampshire. for support. Thanks to Jamie Adams for CIS contnbutions. Eelgrass dis-

tnbution coverages and data were provided by Seth Barker, l^aine

which contain eelgrass. While these reser^^es afford no Department of Manne Resources; Charles Costello, Massachusetts legal or direct protection to eelgrass, they are managed Department of Environmental Protection; the Narragansett Bay Estuary

for research purposes and knowledge of eelgrass Program, Rhode Island; Ron Rozsa, Connecticut Department of Environ- distribution within these reserves has been established. mental Protection; the Peconic Estuary Program, New York; Richard

Most NERR sites have programs that include public Lathrop, Grant F. Walton Center for Remote Sensing and Spatial Analysis,

awareness and outreach education. Rutgers University, New Jersey. This is Jackson Estuarme Laboratory

There is some increasing scientific, policy and contnbution number 392 and AES scientific contnbution number 2144.

public awareness and interest in seagrass within the region. A group of scientists and managers meets AUTHORS

annually under the auspices of the US Environmental Frederick T. Short and Catherine A. Short, University of New Hampshire, Protection Agency to discuss eelgrass and receive an Jackson Estuarme Laboratory, 85 Adams Point Road, Durham, NH 03824. update on research activities. A multimillion dollar port USA. Tel: +1 603 862 2175. Fax: +1 603 862 1101. E-mail:

development project in Maine was denied a construction fred.shortBunh.edu

REFERENCES disease: Cause and recurrence of a manne epidemic. Biology eulto/n 173: 557-562. 1 Roman CT, Jaworski N, Short FT, Findlay S, Warren RS [

Estuaries of the Northeastern United States: Habitat and land use 10 Muehlstein LK, Porter D, Short FT [1988], Labynnthula sp., a

signatures. Estuaries 23161; 743-764. marine slime mold producing the symptoms of wasting disease in 465-472, 2 Short FT, Davis RC, Kopp BS, Short CA, Burdick DM [2002 in press). eelgrass, Zostera marina. Manne Biology')'!:

Site selection model for optimal restoration of eelgrass, Zostera 11 Milne LJ, Milne MJ [1951], The eelgrass catastrophe. Scientific 52-55, manna L. Marine Ecology Progress Series. American 184:

3 Short FT, Burdick DM, Short CA, Davis RC, Morgan PA [20001. 12 Short FT, Burdick DM [19961, Quantifying eelgrass habitat loss in

Developing success cntena for restored eelgrass, salt marsh and relation to housing development and nitrogen loading in Waguoit 730-739. mud flat habitats. Ecological Engineering 15: 239-252. Bay, Massachusetts, Estuaries 19131: 4 Thayer GW, Kenworthy WJ, Fonseca MS [1984], The Ecology of 13 Short FT, Burdick DM, Granger S, Nixon SW [1996]. Long-term Eelgrass Meadows of the Atlantic Coast: A Comn)unity Profile. US decline in eelgrass, Zostera marina L., linked to increased housing Dl, ledsl Fish and Wildlife Sen/ice FWS/OBS-84/24. 85 pp. development. In: Kuo J, Phillips RC, Walker Kirkman H International 5 Short FT, Burdick DM, Wolf J, Jones GE [19931. Eelgrass in Seagrass Biology: Proceedings of an Workshop, 1996. University Estuarme Research Reserves along the East Coast, USA, Part /.- Rottnest Island. Western Australia, 25-29 January Australia, 291-298. Declines from Pollution and Disease and Part II: Management of of Western Australia, Nedlands, Western pp Eelgrass Meadows. Jackson Estuarme Laboratory, University of 14 Short FT (edl [19921. The Ecology of the Great Bay Estuary. New Profile Bibliography. New Hampshire, Durham, NH. 107 pp. Hampshire and Maine: An Estuarme and

6 Heck KL Jr, Able KW, Roman CT, Fahay MP [19951. Composition, Jackson Estuarme Laboratory, University of New Hampshire,

abundance, biomass and production of macrofauna in a New Durham, NH, 222 pp. England estuary: Comparisons among eelgrass meadows and 15 Richardson FD [19801. Ecology of Ruppia maritima L. in New

other nursery habitats. Estuaries 18(21: 379-389. Hampshire lUSAl tidal marshes Rhodora82: 403-439

7 Rasmussen E [1977]. The wasting disease of eelgrass {Zostera 16 Richardson FD [19831. Variation, Adaptation, and Reproductive

manna] and its effects on environmental factors and fauna. In: Biology in Ruppia mantima L. Populations from New Hampshire

McRoy CP, Helfferich C ledsl Seagrass Ecosystems: A Scientific Coastal and Estuarme Tidal Marshes. PhD dissertation, University

Perspective. Marcel Dekker, New York, pp 1-52. of New Hampshire, Durham. 147 pp.

8 Muehlstein LK, Porter D, Short FT [19911. Labyrinthula zosterae sp. 17 Kurland JM [1994], Seagrass habitat consereation: An increasing

nov, the causative agent of wasting disease of eelgrass, Zostera challenge of coastal resource management in the Gulf of Maine. In:

marina. Mycologia 83121: 180-191. Wells PG, Ricketts PJ ledsl Coastal Zone Canada '9i: Cooperation

9 Short FT Muehlstein LK, Porter D [19871, Eelgrass wasting m the Coastal Zone: Conference Proceedings. Vol. 3. Coastal Zone Regional map: North America XI

60'

.•<^, 60° ARCTIC OCEAN

• 1 © BERING' SEA .

• •®.

^ft:' •

Hudson • Bay

• . •

©.

40°

» • y / 40' /

f • i '

20° Gulf of ^ , '"^ **^ Mexico ^ — "^' I

^ V' PACIFIC OCEAN ^fe^m

i N 1^H' '9^

i- 300 600 900 1200 1500 km 140° ^^= 100" Sl^^^r" XII WORLD ATLAS OF SEAGRASSES

DIVERSITY OF SEAGRASS HABITATS

Flowering shoots of Zostera manna in the Netherlands.

Enhalus acoroides and Cymodocea rotundata in Puerto

Galera, Philippines.

intertidal Thalassia nempnchii on a high energy stiore ot Kosrae, Federated Halophita tncostata in the Great Barrier Reel,

States of Ivlicronesia Queensland, Australia

Halophila spinulosa in Papua New Guinea Phyllospadix lorreyi, growing on solid rock with kelp m Ensenada. lulexico. rT;

-.1/,.^ The western North Atlantic 215

Canada Association, Bedford Institute of Oceanography, Dartmoutfi, 38 Connolly RM [1995] Effects of removal of seagrass canopy on

Nova Scotia. assemblages of small, motile invertebrates, fjtarine Ecology

18 Armstrong MP [19951. A Comparative Study of ttie Ecology of Progress Series ]]S: 129-194. Smootti Flounder, Pleuronectes putnami. and Winter Flounder, 39 Lalumiere R. Messier D. Fournier JJ. McRoy CP [1994]. Eelgrass

Pleuronectes amencanus, from Great Bay Estuary, New meadows in a low arctic environment, the northeast coast of James

Hampshire. PhD dissertation. University of Nev» Hampshire. 147 pp. Bay, Quebec. Aquatic Botany iT. 303-315.

19 Short FT, Burdick Dl^, Bosworth W, Grizzle RE. Davis RC 11998], 40 Wyllie-Echeverria S. Personal commmunication. Nev» Hampshire Port Authority (litigation Pro|ect Progress Report. 41 Robertson Al, Mann KH [1984]. Disturbance by ice and life history

June 1998. Prepared for the New Hampshire Port Authority and the adaptations of the seagrass. Zostera marina. Manne Biology SO:

New Hampshire Dept. of Transportation. 59 pp. 131-142.

20 Karnofsky EB. Atema J. Elgin RH [1989]. Natural dynamics of 42 Dobson JE. Bright EA. Ferguson RL. Field DW. Wood LL. Haddad population structure and habitat use of the lobster, Homarus KD. Iredale H. Jensen JR [19951. NOAA Coastal Change Analysis

amencanus, in a shallow cove. Bmlogicat Bulletin 176: 247-256. Program IC-CAPl: Guidance for Regional Implementation. NOAA

21 Short FT, Matso K. Hoven H, Whitten J. Burdick DM, Short CA Technical Report NMFS 123. US Dept. of Commerce, Seattle.

[2001]. Lobster use of eelgrass habitat in the Piscataqua River on Washington. 92 pp.

the New Hampshire/Maine Border. USA. Estuaries 24; 249-256. 43 Kemp WM. Boyton WR. Stevenson JC. Twilley RR. Means JC [1 9831.

22 Gotceltas V. Eraser S. Brown JA [1997]. Use of eelgrass beds The decline of submerged vascular plants in the upper Chesapeake IZostera manna] by juvenile Atlantic cod [Godus mortiua]. Canadian Bay: A summary of results concerning possible causes. Ivlanne

Journal of Fisheries and Aquatic Sciences 54: 1306-1319. Technology Society Journal 7: 78-89. 23 Normadeau Associates (19791. Piscataqua River Ecological Studies. 44 Short R. Mathieson AC. Nelson Jl [1986]. Recurrence of the

1978 Monitoring Studies. Report No. 9 for Public Service Company eelgrass wasting disease at the border of New Hampshire and Series 29: 89-92. of New Hampshire. Volume 1: Physical/chemical Studies. Biological Maine. USA. Marine Ecology Progress

Studies. Normadeau Associates. Inc., Bedford, NH. 479 pp. 45 den Hartog C [1994]. The dieback of Zostera marina in the 1930s in

24 Short FT [1988]. Eelgrass-scallop Research in the Niantic River the Wadden Sea: An eye witness account by van der Werff A. Waterford-East Lyme, Connecticut Shellfish Commission, Final Netherlands Journal of Aquatic EcologylS: 51-54. Natural Report. 12 pp. 46 Short FT. Wyllie-Echeverria S [19961. and human-induced 25 Newell CR, Hidu H. McAlice BJ, Podniesmski G. Short F, Kindblom disturbance of seagrasses. Environmental Conservation 23111:

L [1991], Recruitment and commercial seed procurement of the 17-27.

blue mussel Mytilus edulis in Maine. Journal of ttie World 47 Zieman J [19761. The ecological effects of physical damage from

Aquaculture Society 22: 134-152. motorboats on turtle grass beds in southern Florida. Aquatic

26 Grizzle RE. Short FT. Newell CR. Hoven H. Kindblom L [1996]. eotany 2: 127-139.

Hydrodynamically induced synchronous waving of seagrasses: 48 Walker Dl, Lukatelich RJ, Bastyan G. McComb AJ 11989]. Effect of

"Monami" and its possible effects on larval mussel settlement. boat moorings on seagrass beds near Perth. Western Australia. Journal of Experimental Manne Biology and EcologylOb: 165-177. Aquatic Botany 2b: 69-77.

27 Carlton JT, Vermel] GJ. Lindberg DR. Carlton DA. Dudley EC [19911. 49 Burdick DM. Short FT [19981. Dock Design with the Environment in

The first historical extinction of a marine invertebrate in an ocean Mind: Minimizing Dock Impacts to Eelgrass Habitat. UNH Media

basin: The demise of the eelgrass limpet Lottia alveus- Biological Services. Durham. NH. CD-ROM.

Bulletin 180: 72-80. 50 Burdick DM. Short FT [19991. The effects of boat docks on eelgrass

28 Nixon SW. Personal communication. beds In coastal waters of Massachusetts. Environmental

29 Wyllie-Echeverria S. Cox PA [1999]. The seagrass \Zostera marina, Management 22: 231-240.

[ZOSTERACEAEll industry of Nova Scotia 11907-19601. Economic 51 Short FT. Jones GE. Burdick DM [1991], Seagrass dechne:

eofany 53: 419-426. Problems and solutions. Proceedings of Seventh Symposium on

30 V^yllie-Echeverna S. Arzel P, Cox PA 120001. Seagrass conservation: Coastal and Ocean Management/ASCE. Long Beach. CA Lessons from ethnobotany. Pacific Conservation Biology^: 329- 52 ASMFC [19991. Evaluating Fishing Gear Impacts to Submerged

335. Aquatic Vegetation and Determining Mitigation Strategies. Atlantic

31 Lathrop RG. Styles RM, Seitzinger SP, Bognar JA [2001]. Using GIS States Marine Fisheries Commission. Washington. DC.

modeling approaches to examine the spatial distribution of 53 Dennison WC. Marshall GJ. Wigand C [1989]. Effect of "brown tide"

seagrasses in Barnegat Bay, New Jersey Estuaries 24: 904-916. shading on eelgrass l/os/era manna LI distributions. Coastal and

32 Neckles HA, Short FT. Barker S, Kopp B [20011. Evaluation of Estuarine Studies 35: 675-692.

Commercial Fishing Impacts to Eelgrass in New England. 54 Short FT, Neckles H [1999]. The effects of global climate change on Abstract. Estuarine Research Federation Conference, Nov. 3-8, St seagrasses. Aquatic Botany b2: 169-196.

Petersburg. FL. 55 Short FT, Burdick DM. Kaldy JE [1995]. Mesocosm experiments

33 Barker S. Marine Department of Marine Resources. Personal quantify the effects of eutrophication on eelgrass. Zostera manna

commmunication. L. Limnology and Oceanography l>0: 740-749.

34 Christiansen C. Christoffersen H, Dalsgaard J. Nornberg P [1981]. 56 Deegan LA. Wright A. Ayvazian SG. Finn JT. Golden H. Merson RR.

Coastal and nearshore changes correlated with die-back in Harrison J [20021. Nitrogen loading alters seagrass ecosystem

eelgrass IZostera manna]. Sedimentary Geology 2S: 168-178. structure and support of higher trophic levels. Aquatic

35 Hine AC. Evans MW. Davis RA. Belknap DA [1987]. Depositional Consen/ation ]2{2]: m-212.

response to seagrass mortality along a low-energy, barrier-island 57 Burdick DM. Short FT. Wolf J [19931. An index to assess and

coast: West-central Florida. Journal of Sedimentary Petrology monitor the progression of the wasting disease in eelgrass. Zostera 57131:431-439. manna. Manne Ecology Progress Series 94: 83-90.

36 Duarte CM [19951. Submerged aquatic vegetation in relation to 58 Davis R, Short FT 11997]. An improved method for transplanting

different nutrient regimes, Opfieliail: 87-112. eelgrass. Zostera marina L. Aquatic Botany b'): 1-16.

37 Olesen B [19961. Regulation of light attenuation and eelgrass 59 Valiela 1. Costa J. Foreman K. Teal JM. Howes B. Aubrey D [1990].

Zostera marina depth distribution in a Danish embayment. Marine Transport of groundwater-borne nutrients from wastelands and

Ecology Progress Series 134: 187-194. their effects on coastal waters. S/ogeoc/iem/st/y 10: 177-197. 216 WORLD ATLAS OF SEAGRASSES

21 The seagrasses of THE MID-ATLANTIC COAST OF THE UNITED STATES

E.W. Koch

R.J. Orth

mid-Atlantic region of the United States presently unvegetated. In contrast, the middle and Theincludes tour states: Delaware, Maryland, Virginia southern areas are colonized by monospecific stands or

and North Carolina. It is characterized by by intermixed beds of seagrass (usually two species]. numerous estuaries and barrier-island coastal lagoons The beds can vary from small and patchy to quite

with expansive salt marshes and seagrass beds in most extensive. The largest seagrass bed in the Chesapeake

shallow-water areas'". There are no rocky shores. Hard Bay IS composed of a mixture of Zostera marina and substrates are either man-made Irock jetties and Ruppia maritima and covers 13.6 km^ riprap or wood pilings) or biogenically generated Seagrass habitat provides food and refuge from loyster and worm reefs). Sediments are predominantly predators for a wide variety of species, some of which

quartz sand in shallow exposed areas with finer grain have recreational and commercial significance. The

sediments in deeper or well-protected areas. Marsh invertebrate production in just one seagrass bed in the peat outcroppings or cohesive sediments are lower Chesapeake Bay was estimated to be OM metric

sometimes found in the subtidal areas adjacent to tons per year'". Seagrass beds in Chesapeake Bay are eroding marshes. Climatic variations are large with air reported to be important nursery areas for the blue temperatures ranging from -10°C to 40°C and water crab, Callinectes sapidus, whose commercial harvest

temperatures ranging from 0°C to 30°C. Tides are can yield close to A5000 metric tons in a good year.

equal and semi-diurnal but relatively small in range The bay scallop [Argopecten irradians] fishery is also (maximum of 1.3 m during spring tides]. closely tied to seagrass abundance because the larval

The largest estuary in the country, the stage attaches its byssal thread to seagrass leaves.

Chesapeake Bay 118130 km'l, occurs in this area. Its The decline of seagrasses in Virginia's coastal bays in watershed covers 165760 km^ drains from six states the 1930s led to the complete disappearance of the bay

and is inhabited by more than 15 million people. scallop, and loss of a substantial commercial fishery.

Additionally, the estuanne system of the state of North Seagrasses have not returned to this region, nor have

Carolina is the third largest in the country, bay scallops. Other important local fisheries encompassing more than 8000 km" with a watershed of sometimes (but not always] associated with seagrasses

more than 63 000 km''. Other estuaries in the mid- include hard clams [Mercenaria mercenaria] and fish

Atlantic include the Delaware Bay and a series of of commercial and recreational importance, e.g. barrier-island coastal lagoons. striped bass [Morone saxatalis], spotted sea trout

Flowering aquatic plants are common in the [Cynoscion nebulosus], spot [Leiostomus xanttiurus]

estuaries of the mid-Atlantic region. They are often and gag grouper [Mycteroperca microiepis]'^'.

referred to as submersed aquatic vegetation ISAV). This

term includes all flowering aquatic plants from BIOGEOGRAPHY

freshwater to marine habitats. The term "seagrass" is The state of North Carolina is an interesting

used exclusively for species that occur in the higher biogeographical boundary for seagrasses in the North

salinity zones |>10 psul'^'^'. Only three seagrass species Atlantic. On the east coast of the United States it is the

are found in the mid-Atlantic region: Halodule wrightii southernmost limit for the distribution of the Ishoal grass], Ruppia maritima (widgeon grass) and temperate seagrass Zostera marina and the

Zostera marina (eelgrass). The northernmost area of northernmost limit for the distribution of the tropical

the mid-Atlantic (Delaware estuaries and bays) is seagrass Halodule wrighti)''\ Due to their existence at :

The mid- Atlantic coast of the United States 217

the limits of their thermal tolerance, the seagrasses found in this boundary zone are expected to show early effects of global warming in this area. Ruppia nnaritima New Jersey

is able to tolerate a broad range of temperatures and is found throughout the mid-Atlantic region and possibly along the coasts of South Carolina and Georgia. Delaware • Seagrasses in the mid-Atlantic region occur in Bay L Majyland wave-protected habitats. The extensive lagoon system

Ifrom Delaware to North Carolina] is delimited to the Delaware Rehithalti Bay east by long barrier islands. These islands provide shelter from oceanic waves, making the lagoons ideal - vS< * habitats for Zostera marina, Ruppia maritima and Chincoteague Ba)Bav ^ Halodute wrightii. No seagrasses Ibut seagrass wrack, VJp^_ -.^ Assateague Island including reproductive shoots with viable seeds! have National Seashore Park been reported for the exposed shores of the Atlantic

Ocean. The seagrasses in the mid-Atlantic region also

llf.UI/K'llU* f: colonize areas covering a wide range of salinities; from lim f full-strength seawater 130-32 psu) near the mouths of the estuaries to mesohaline zones 110-20 psul in the Currituck Sound middle portion of the estuaries. Due to its ability to Virginia tolerate relatively low salinities, Ruppia maritima is ATLANTIC OCEAN usually the seagrass that extends farthest into the estuaries. NoffoK,,

The distribution of seagrasses in the mid-Atlantic region is restricted to shallow waters because of the *•' high suspended sediment and nutrient loadings leading '\ to relatively turbid waters in seagrass habitats (light ». Alhemtirle r-' SvumJ. attenuation coefficients higher than 1 per m^ are quite ^ common). In relatively pristine areas (North Carolina sounds adjacent to barrier islands and Chincoteague

Bay], the maximum depth to which seagrasses grow ^'Pamlico

i. Souml^ can be as great as 2 m, while in habitats associated with the mainland and eutrophic [i.e. nutrient enriched! conditions (Chesapeake Bay, North Carolina sounds North Carolina near the mainland], the maximum vertical distribution t^ Raleigh Bay only reaches depths of 0.5 to 1.0 m" ". In other areas, such as the Delaware coastal bays, seagrasses are Core Sound ICape almost completely absent due to high water turbidity. Lookout

HISTORICAL PERSPECTIVES 10 20 30 40 50 Kilometers Sneads Ferry No record exists of the extent of the vegetation prior to the 1930s, but anecdotal evidence of historical changes Map 21.1 in eelgrass"'™ suggest that seagrasses occurred in the Tlie mid-Atlantic coast of the United States

Chesapeake Bay region in the mid- to late 1800s"". In the pre-colonial period (1800s!, seagrasses are Atlantic region occurred in the 1930s as Zostera marina believed to have formed extensive beds in estuaries and was affected, and in many locations eliminated, by lagoons in the mid-Atlantic region covering the coastal wasting disease""'". The loss of eelgrass was reported bays in their entirety. It is not known to what depths throughout the northern Atlantic. In some areas in the seagrasses used to grow in the estuaries, but it may mid-Atlantic (Chesapeake Bay, Chincoteague Bay, have been as deep as ^ m. When Zostera marina beds North Carolina sounds], eelgrass beds slowly were extensive, the seagrass was used for packing and recovered. In the Delaware coastal bays (Indian River upholstery stuffing. It was also used for insulation of and Rehoboth Bays], recovery of eelgrass through the buildings due to its low flammability and excellent 1950s ended, apparently due to eutrophication. In the insulating properties. coastal bays of the lower eastern shore of Virginia,

A massive decline of seagrasses in the mid- eelgrass was completely eliminated and never 218 WORLD ATLAS OF SEAGRASSES

Figure 21.1 recovered. Ttie decline in the 1 930s was complicated by

Seagrass distribution Imainly Zostera marina and Ruppia maritima a fiurricane of unprecedented proportions in August

but possibly also a few hectares of other SAV species) in 1933. Tfiere is no evidence of eelgrass ever being

Chesapeake Bay present in Delaware Bay.

250 PRESENT DISTRIBUTION Although! rare, sparse and small eelgrass beds are

present in the coastal bays of Delaware la result of 200 ll restoration efforts]. They are too small to map and also

ephemeral in nature. There is very little seagrass in the

lllllil state of Delaware. Unprecedented changes to eelgrass populations

100 in Chesapeake Bay occurred following Tropical Storm ------Agnes in June 1972. Eelgrass beds in the upper portions of Chesapeake Bay were the most influenced 50 by the effects of the runoff How salinities and high turbidity!, which occurred during the peak growth period for eelgrass. While the distribution of 198i 86 90 92 9i 96 98 2000 seagrasses in Chesapeake Bay (Maryland and Virginia!

had been partially documented in 1971 and 1974, the

Source: Based on data from the Virginia Institute of Marine Science SAV first baywide survey was conducted in 1978, and annual

mapping program. surveys began in 1984. Based on these data, seagrass

distribution in Chesapeake Bay was observed to increase 63 percent between 1985 and 1993, but distribution then declined 27 percent between 1993 and

Figure 21.2 2000 (Figure 21.11. In contrast, from 1986 to 2000,

Changes in seagrass [Zostera marina and Hatoduie wrightiil seagrass distribution in the coastal bays of (Maryland

distribution in the Cape Lool

North Carolina! between 1985 and 1988 21.11. Presently, the seagrasses in Chesapeake Bay

show declines in some areas while recovering in

others. There is great interannual variation, making it

difficult to estimate the area of seagrass.

In North Carolina, where the seagrass habitats are dominated by shallow areas protected by extensive barrier islands, seagrass distribution has only recently

been mapped. Core Sound was mapped in 1988 and

inside of Cape Hatteras in 1990. The area south of Cape

Lookout has not yet been mapped but it is known that no seagrasses are found south of Sneads Ferry (80 km

north of the city of Wilmington!"". The lack of

seagrasses in Albermarle Sound is believed to be the

result of the high water turbidity in this area. The

western portion of Pamlico Sound is also mostly

unvegetated due to the long fetch and consequent high turbidity during strong wind events. Although there has

not been a sustained effort to map seagrasses in North Carolina, researchers have been investigating aspects

Note: Areas of seagrass coverage that did not change between the two of seagrass ecology and report no noticeable changes

years are shown in green cross-hatch; areas of gam are shown by the in species composition or distribution since the

vertical white hatching and areas of loss are shown by the horizontal white 1970s"^'. One quantitative effort (Figure 21.2! confirms

hatching. this. In the Core Sound area [between Drum Inlet and Cape Lookout! seagrass distribution was generally

Source: Poster produced by the Beaufort Lab entitled SAV Habitat in 1985 consistent between the two years in which it was

and 1988: Cape Looltout to Drum Inlet, Nortl^ Carolina, by Randolph mapped. In 1985 there were 7 km' of seagrass and in

Ferguson, Lisa Wood and Brian Pawlak. 1988 there were 6.6 km', only a 5.7 percent loss. There

J" The mid-Atlantic coast of the United States 219

were 151 beds in 1985 and U9 in 1988. Two negative impact on seagrasses and their habitats"".

anthropogenic impacts on seagrasses were noted There is also no doubt that propeller scars have a between 1985 and 1988: a clann harvesting operation detrimental effect on seagrasses'*"''". The effect is dug up seagrasses. while in another area dredge spoil similar to that described for clam dredging although

was deposited on a seagrass bed"". In North Carolina, the scars are narrower This problem is most severe in seagrass beds have been relatively stable since the North Carolina but has also been documented in

1970s at approximately 80 l

seagrass beds in North Carolina also suffered the Dredging and maintenance dredging of channels

declines observed in the Chesapeai

PRESENT THREATS activities. Maryland is currently re-evaluating its The main threats to seagrasses in the mid-Atlantic dredging regulations. region today are eutrophication and high turbidity from Sea-level rise has the potential to pose a threat to

poor land-management practices. As the coastal zone seagrasses in the mid-Atlantic. The vulnerability of continues to be developed, nutrient loads and coastal zones to sea-level rise has been classified as suspended sediments in the water column tend to very high in this region, the highest risk on the east increase"". These nutrients may come from well- coast of the United States. Unfortunately, our defined sources such as a sewage treatment plant, a understanding of how sea-level rise affects seagrasses pig farm or a golf course, but a large amount of is in its infancy. It is known that sea-level rise leads to nutrients also comes from non-point sources such as marsh erosion'""' and the eroded sediments are then farmland and groundwater nutrient enrichment by transported to coastal waters where seagrass beds septic systems. As a result of increased nutrient may occur This may lower the light available to loading, epiphytic algae may grow directly on the seagrasses and may lead to their decline or loss. seagrass leaves while blooms of phytoplankton or The loss of the seagrasses could then lead to further macroalgae may occur in the water column. These due to the loss of wave attenuation processes decrease the amount of light that reaches previously provided by the seagrasses. the seagrasses and cause their decline or death. Most Although a natural event, a storm can be water bodies in the mid-Atlantic are now detrimental to seagrasses. Hurricanes are quite phytoplankton dominated, and the few pristine lagoons common in the mid-Atlantic, especially in the state of are showing signs of deterioration resulting from North Carolina, and have shown to be detrimental to blooms of nuisance macroalgae such as seagrasses by removing the plants, eroding the Chaetomorpha Unum and Ulva tactuca Imats up to 1.5 sediment, burying seagrass beds and/or increasing m thick). These algal blooms have adversely impacted turbidity of the water''*'. It is expected that with global healthy seagrass beds Isee Case Study 21.1] as well as warming hurricane frequency and intensity will recent eelgrass restoration efforts in the Delaware increase. With that, the threat to seagrasses is also bays. coastal expected to increase. However, little quantitative data

Seagrass beds are vulnerable to disruption by exist on the effects of hurricanes on long-term stability commercial fishing practices, especially clam and of seagrass beds in this region. Hurricanes are more scallop dredging. Hydraulic clam dredging digs deep frequent in the fall period (September and October) and trenches or circles into the sediments Isee Case Study it is possible that water quality effects may be marginal

21.1). If these are vegetated by seagrasses, the plants as temperatures are lower and growth is generally less are lost and the recovery is relatively slow"". Clam than in the spring. dredging also has a negative impact on other fisheries.

The trenches caused by hydraulic clamming in POLICIES AND REGULATIONS seagrass beds prevent crabbers from pulling their No state or federal marine parks exist in the mid- scrapes through the seagrass beds (a practice that Atlantic region, but several protected islands include causes relatively little damage to the plants), directly the adjacent waters in their jurisdiction. The national threatening their livelihood. estuarine research reserves in Maryland and North As coastal areas become more heavily populated, Carolina include seagrass habitats, although no more individuals also want to enjoy water-related protection is afforded by this designation. The activities. Boat-generated waves and turbulence have a Assateague Island National Seashore Park protects its WORLD ATLAS OF SEAGRASSES

adjacent seagrasses. The state ot Delaware currently process. Section 10 of the Rivers and Harbors Act, also

has no protection for seagrasses in its regulatory administered by the Army Corps, regulates all activities framework. The total area of protected seagrass beds in navigable waters including dredging and placement has not been identified for the mid-Atlantic. of structures. At the federal level, seagrasses are afforded On a regional basis, considerable and cooperative some protection under Section ^04 of the Clean Water efforts by scientists, politicians, federal and state Act 133 use 1341-1987) and Section 10 of the Rivers resource managers, and the general public have

and Harbors Act [33 USC /103). which regulate the developed policies and plans to protect, preserve and

discharge of dredged or fill material into US waters. enhance the seagrass populations of Chesapeake Authority for administering the Clean Water Act rests Bay''". The foundation for the success of these with the US Environmental Protection Agency. management efforts has been the recognition of the

Seagrass protection under the Act is provided by a habitat value of seagrasses to many fish and shellfish,

federal permit program that is delegated to and and the elucidation of linkages between seagrass administered by the US Army Corps of Engineers. habitat health and water quality conditions. Because of Potential impacts on "special aquatic sites", such as these linkages, the distribution of seagrasses in

seagrass beds, are considered in the permit review Chesapeake Bay and its tidal tributaries is being used

Case Study 21.1 SEAGRASSES IN CHINCOTEAGUE BAY: A DELICATE BALANCE BETWEEN DISEASE, NUTRIENT LOADING AND FISHING GEAR IMPACTS

Chincoteague Bay is one of the most pristine water an extensive dune system along the Atlantic coast

bodies in the mid-Atlantic. It is a relatively shallow and marshes along the Chincoteague Bay shoreline. coastal lagoon (average depth 1.2 ml with limited Seagrasses in Chincoteague Bay are found freshwater input and long residence times (flushing almost exclusively on the eastern shores. Due to its

of 7.5 percent per day). Salinities are close to those relatively shallow depth, it is believed that the entire

of seawater (26-31 psul and nutrient levels are bay used to be colonized by Zostera manna. In the relatively low l<10 pM total nitrogen,

phosphate'"'). The western shore of Chincoteague wasting disease after which it slowly began to

Bay IS characterized by extensive salt marshes and recolonize the eastern shore. The recovery of the

isolated, small towns representing an area of low seagrasses in Chincoteague Bay has been well developmental pressure Hess than 0.04 person per documented since 1986 (see figure, left). Although

hectare). The eastern shore is located adjacent to an there was a 40 percent increase in the human

unpopulated (but accessible to tourists) barrier population on the western shore of Chincoteague island (Assateague Island National Seashore) with Bay between 1980 and 2000, the total nitrogen and phosphorus loadings declined between 1987 and

1998 lin some areas as much as 50 percent). This is

believed to be due to the construction of sewage treatment plants and the reduction of the amount of

fertilizers used on the farms west of Chincoteague

Bay As a result, phytoplankton concentration is low and light penetration relatively deep. Seagrasses flourished during this period showing a 238 percent increase m distribution between 1986 and 1999. In 1996, seagrasses even began colonizing the western shore which had remained unvegetated since the 1930s.

One of the first threats to seagrass in

Chincoteague Bay since its decimation in the 1930s

90 92 came from a fisheries practice'™. In 1997, severe damage to the seagrass beds was noted and

Recovery and recent decline of seagrass [Zostera marina and attributed to two types of hard clam fishing gear:

Ruppia maritima] distribution In Chincoteague Bay. hydraulic dredges and modified oyster dredges Isee

) The mid-Atlantic coast of the United States 221

as an initial measure of progress in the restoration of Environment and the Maryland Department of Natural living resources and water quality. Restoration targets Resources are responsible for issuing a permit, which and goals fiave been established to link demonstrable includes a plan showing the site at which the activity is improvements in water quality to increases in seagrass proposed, a dated map of current seagrass distribution abundance'"'. The states of Maryland and Virginia each and the extent of seagrass to be removed. Maryland have separate regulatory agencies to oversee activities does prohibit one type of commercial fishing activity, that could be injurious to seagrass populations. Both hydraulic clam dredging, in specific regions of its state states are committed to protecting seagrass habitat waters. Hydraulic clam dredging is prohibited both while maintaining viable commercial fisheries and within a specified distance from shore, which varies by aquaculture operations. political boundaries INRA 4-10381, and in existing

Maryland State Code COMAR 4-213 specifically seagrass beds INR 4-1006.1 1, as determined by annual prohibits damage to seagrasses for any reason except aerial mapping surveys. for commercial fishing activities and certain specific In Virginia, permits to use state-owned situations such as clearing seagrasses from docks, submerged lands now include seagrass presence as a piers and navigable waters. If seagrasses will be factor to be considered in the application process (Code adversely affected, the Maryland Department of the 28.2-1205 |A| '". amended in 19961. On-bottom shellfish

photograph, right). The seagrass area affected by seagrasses beneath and leaving long scars visible

hydraulic dredging increased from 0.53 km' in 1996 via aerial photography Managers are currently

to 5.08 km^ in 1997, while modified oyster dredge attempting to determine the source of the nutrients

scars increased from 10 in 1995 to 218 scars in 1997. fueling these macroalgal blooms and threatening

Analysis of the recovery from both types of scarring the seagrasses of Chincoteague Bay showed that some scars require more than three

years to revegetate to undisturbed levels. Once

notified of these impacts, resource managers in Maryland and Virginia responded within several

months to protect seagrasses through law and regulation preventing clam dredging within seagrass

beds. In Virginia, the new regulation was successful

in reducing scarring, but required later revisions for

successful enforcement. In Maryland, however,

procedural requirements to fully implement the law required additional time, during which scarring

increased to 12.57 km' in 1999. This issue has demonstrated the importance of close linkages between the scientific research community, poli-

ticians, management agencies, law enforcement agencies and the public, as well as the importance

of sanctuaries or protection zones to prevent

damage to critical seagrass habitats. Over the last three years, seagrasses in Chincoteague Bay have been exposed to another stress: the blooms of the nuisance macroalga Aenal ptiotograph taken in 1998 of a portion of Chincoteague Chaetomorpha tinum, suggesting that this formerly Bay, Virginia, seagrass bed stiowing damage to the bed from a pristine area may be experiencing eutrophication. modified oyster dredge. Indeed, nutrient data shows a renewed increase in

total nitrogen and phosphorus loads in 1999 and Notes: Arrows point to circular "donut-shaped" scars created by 2000. While pristine systems are dominated by the dredge being pulled by a boat m a circular manner The light

seagrasses, systems in the early and late stages of areas in each circle represent areas that had vegetation that eutrophication are dominated by macroalgae and/or was uprooted and are now unvegetated. The dark spot within

phytoplankton, respectively'™'. The macroalgal mats each circle is seagrass that was not removed. The long, lighl- are observed in Chincoteague Bay over the last two cotored streaks emanating from some of the scars years can be as thick as 1.5 m, killing the sediment plumes created by the digging activities of sting rays.

c 222 WORLD ATLAS OF SEAGRASSES

aquaculture activities requiring structures are now minimized when docks, piers, bulkheads, boat ramps, prohibited from being placed on existing seagrass beds groins, breakwaters, culverts and bridges are

14-VAC 20 335-10, effective January 19981. In 1999, the constructed.

Virginia Marine Resources Commission was directed

ICode 28.2-120^.1) to develop guidelines with criteria to ACKNOWLEDGMENTS

define existing beds and to delineate potential Mark Finkbeiner, Ben Anderson and Bnan Glazer are thanked for their

restoration areas. Dredging for clams Ihard and soft) in help and for sharing their data. Mike Durako and Mark Fonseca

Virginia is prohibited in waters less than 1.2 m where contnbuted valuable information. Lisa Wood and Randolph Ferguson

seagrasses are likely to occur. A special regulation was developed the seagrass vectors in Figure 21,2. Mike Naylor and several of

passed for seagrasses in the Virginia portion of the above listed colleagues provided comments on the report. Melissa

Chincoteague Bay 14-VAC 20-1010) where clam and Wood and Dave Wilcox provided technical support. This is contribution

crab dredging is prohibited within 200 m of seagrass number 3613 from Horn Point Laboratory, University of Maryland Center

beds. Because of enforcement issues, the Virginia for Environmental Science and contribution number 2491 from the

regulation has recently been modified 14-VAC 20-70-10 Virginia Institute of Marine Science, College of William and Mary,

seq.) to include permanent markers with signs Gloucester Point, Virginia. delineating the protected seagrass™.

In the state of North Carolina, regulations

involving seagrasses are not as strong as in Virginia AUTHORS

and fvlaryland. North Carolina protects seagrass beds Evamaria W. Koch. Horn Point Laboratory, University of Maryland Center

along underdeveloped areas. These areas are to be for Environmental Science, PC. Box 775, Cambridge, MD 21613, USA.

used mainly for education and research although some Tel: +1 410 221 8418. Fax: tl 410 221 8490. E-mail; kochldhpl.umces.edu recreational activities are permitted. The dredging of

channels is regulated such that seagrass beds must be Robert J. Orth, Virginia Institute of Manne Science, School of Marine

avoided. Damage to seagrasses is also to be Science, College of William and Mary, Gloucester Point, VA 23062, USA.

REFERENCES 12 Renn CE[1934). Wasting disease of Zosfera in American waters.

1 Orth R, Heck JKL Jr, Diaz RJ [1991]. Littoral and intertidal Nature 134: 416.

systems in the mid-Atlantic coast ot the United States. In: 13 Tutin TG [1938). The autecology of Zostera marina in relation to its

Mathieson AC, Nienhuis PH ledsl fcosyslems of the World 24: wasting disease. NewPhytology21: 50-71.

Intertidai and Littoral Ecosystems of the World. Elsevier, 14 Durako. Personal communication.

Amsterdam, pp 193-214. 15 Fonseca MS. Personal communication. 2 Orth R [1976). The demise and recovery of eelgrass, Zostera 16 Finkbeiner Personal communication.

marina, in the Chesapeake Bay, Virginia. >5(;uat;c Botany 2: 141- 17 Kemp WM, Twilley RT, Stevenson JC, Boynton WR, Means JC

159. [1983). The decline of submerged vascular plants in Upper

3 Moore KA, Wilcox DJ, Orth RJ [20001. Analysis ol the abundance of Chesapeake Bay: Summary of results concerning possible causes.

submersed aquatic vegetation communities in the Chesapeake Bay Marine Technology Society Journal 17: 78-89.

fsfuanes 23: 115-127. 18 Stephan CD, Peuser RL, Fonseca MS 12000], Evaluating Fishing

4 Fredette TJ, Diaz RJ, van Montfrans J. Orth RJ [19901. Secondary Gear Impacts to Submerged Aquatic Vegetation and Determining

production within a seagrass bed IZostera marina and Ruppia Mitigation Strategies. Atlantic States Manne Fisheries Commission

maritima] in lower Chesapeake Bay Estuaries 13: 431-440. Habitat Management Senes 5, 35 pp,

5 Ross SW, Moser ML [1995). Life history of juvenile gag, 19 Koch EW [2002], The impact of boat-generated waves on a

Mycteroperca microlepis, in North Carolina estuaries. Bulletin of seagrass habitat. Journal of Coastal Research 37: 66-74,

Marine Science 56: 222-237. 20 Clark PA [1995). Evaluation and management of propeller damage

6 Ferguson RL, Pawlak BT, Wood LL [1993). Flowering of the to seagrass beds in Tampa Bay, Florida. Florida Scientist 58:

seagrass Halodule wrightii in North Carolina, USA. Aquatic Botany 193-196.

46:91-98. 21 Dawes CJ. Andorfer J, Rose C, Uranowski C, Ehnnger N [1997].

7 Dennison WC, Orth RJ, Moore KA. Stevenson JC, Carter V, Regrowth of the seagrass Thalassia testudinum into propeller

Kollar S, Bergstrom P, Batiuk RA [1993), Assessing water scars. Aquatic Botany 59: 139-155.

quality with submersed aquatic vegetation, Bioscience 43: 22 Kearney MS, Stevenson JC, Ward LG [1994), Spatial and temporal

86-94. changes in marsh vertical accretion rates at Monie Bay:

8 Ferguson RU Korfmacher K [1997). Remote sensing and GIS Implications for sea-level nse. Journal of Coastal Research 10:

analysis of seagrass meadows in North Carolina, USA. Aquatic 1010-1020.

Sofany 58: 241-258. 23 Ward LG, Kearney MS, Stevenson JC [1998). Variations in

9 Cottam C [1 934). Past penods of eelgrass scarcity Rhodora 36: sedimentary environments and accretionary patterns in estuarine 261-264. marshes undergoing rapid submergence, Chesapeake Bay Marine

10 Cottam C (1935). Further notes on past penods of eelgrass Geo/ogy151: 111-134.

scarcity Rhodora 37: 269-271. 24 Rooth JE, Stevenson JC [2000]. Sediment deposition patterns in

11 Orth RJ, Moore KA (1984). Distribution and abundance of Phragmites australis communities: Implications for coastal areas

submersed aquatic vegetation in Chesapeake Bay: An histoncal threatened by nsing sea-level. Wetlands Ecology and Management perspective. EstuanesT. 531-540. 8:173-183.

'^} The mid-Atlantic coast of the United States 223

25 Fonseca MS, Kenworthy WJ, Whitfield PE [20001. Temporal 28 Orth RJ, Fishman JR. Wilcox DW, l^oore KA 120021, Identification

dynamics of seagrass landscapes: A preliminary comparison of and management of fishing gear impacts in a recovering seagrass

cfironic and extreme disturbance events. In; Pergent G, Pergent- system m the coastal bays of the Delmarva Peninsula. USA.

Iwlartini C. Buia I^C, Gambi MC ledsl Proceedings ilh International Journal ol Coastal Research 37: 111-119.

Seagrass Biology Workshop, Sept. 25-Oct. 2, 2000. Corsica. France. 29 Boynton WR. Murray L, Hagy JD, Stokes C, Kemp WM 119961. A

pp 373-376. comparative analysis of eutrophication patterns in a temperate

26 Orth RJ, Batiuk RA, Bergstrom PW, l^loore KA (2002a, in coastal lagoon. Estuaries 19: 408-421

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27 Batiuk RA, Orth RJ. l-loore KA. Dennison WC, Stevenson JC,

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Heasly P [1992], Chesapeake Bay Submerged Aquatic Vegetation Habitat Requirements and Restoration Targets: A Technical Synthesis. Chesapeake Bay Program, Annapolis, MD, CBP/TRS

83/92. 248 pp. 224 WORLD ATLAS OF SEAGRASSES

22 The seagrasses of THE GULF OF MEXICO

C.P. Onuf

R.C. Phillips

C.A. Moncreiff

A. Raz-Guzman

J. A. Herrera-Silveira

Gulf of Mexico is a vast basin of water, seagrasses covered 75 percent of the 2740 l

Thespanning 12° of latitude, from 18° to 30°N. and the northwestern Cuban shelf. Seagrasses were limited

17° of longitude, from 81° to 98°W. It is bisected to the part of the shelf shoreward of a fringing reef. A

by the Tropic of Cancer and is largely subtropical; total of tour species were found at 282 stations: however, along the northern edge, up to five days with Thalassia testudinum was found to a depth of 14 m freezing temperatures are probable on an annual basis. and accounted for 97.5 percent of total angiosperm bio-

The coastal fringe is moist, with annual precipitation in mass (190g/m-'l, Syrmgodium filifoime to 16.5m

excess of 1 000 mm, except for southern Texas and and 3.5 g/m', Halophila engelmanni to 14.4 m and

. Precipitation is concentrated in the 0.25 g/m', and Hatophita decipiens to 24.3 m summer period, most pronounced along the coast of and 0.14g/ml Mexico and least pronounced along the coast of

Louisiana. Most of the Gulf of Mexico is fringed by a UNITED STATES broad coastal plain, except for northwestern Cuba and Florida

sections of the Mexican coast near Veracruz. The inner In 1995, there were 9888 km^ of seagrasses along the

continental shelf to a depth of 20 m is broad off the Gulf of Mexico coast of Florida'^'. This includes the

western side of the Yucatan Peninsula, along the coast seagrass beds of Monroe County off the Florida Keys

of Louisiana and along the western side of Florida, but does not include the seagrasses in Card Sound of

extending as much as 80 km offshore to the tip of Biscayne Bay in Dade County Nor does it include the

Florida. Elsewhere, the inner shelf is relatively narrow. large sparse offshore beds of Halophiia decipiens from

Most of the rivers draining into the Gulf of Mexico have the Florida Keys to the Big Bend area. restricted catchments, except along the north shore, The southern tip of the Florida Peninsula most obviously the Mississippi River, and parts of the bordering on the Gulf of Mexico (Monroe and Collier western gulf, including the Rios Bravo IGrandel, Counties! contained 5901 km^ of seagrasses. Monroe Panuco, Grijalva and Usumacinta. Barrier islands and County alone, mostly in Florida Bay and the Florida

spits are prominent features along much of the coast, Keys, contained 54.6 percent of the state's seagrasses.

and coral reefs shelter the large expanse of water off The middle section of the Florida Peninsula's Gulf of

the southern tip of Florida and off the coasts of Mexico coast ILee County to Pinellas County) contained Veracruz, Campeche, Yucatan and northwestern Cuba. 446 km' of seagrasses. The Big Bend region (Pasco

Lunar spring tides are less than 1 m throughout County to Wakulla County! contained 3346 km' while the region. the Florida Panhandle (Franklin to Escambia Counties! contained 195 km' of seagrasses'^'. CUBA Florida Bay and the Florida Keys are relatively No recent assessment has been performed of the shallow and, because of the tourism in the area, the seagrass resources on Cuba's coast bordering the Gulf seagrasses have been particularly subject to damage of Mexico'". Therefore, we must resort to an extensive from boat traffic and sewage pollution from greatly

report of a survey of the northwestern Cuban shelf expanded residential and hotel development, and

conducted in 1972-73'". Fortuitously, this region from marina and boat usage. As much as 17.3 percent of

22 to 23°N and 83 to 85°\N is essentially all of the Cuban seagrass meadow in Monroe County had been scarred

coast that borders the Gulf of Mexico. At that time. by boat propellers, and 32 percent of the 17.3 percent The Gulf of Mexico 225

had been severely scarred . This scarring often leads „ 9g°w MS 80" W , ,. AL Lake ronlchjrtrain PerdiJo Ba\- \Mabile\tt- Bayoay\ Big Bend to a loss of seagrass because of erosion and blow-outs. A I casieu \Biloxi,loxQi. In addition, Florida Bay suffered a massive die-off of LA Sabine^ I Mixsixsippi Stj ^ fj-afif Thalassia testudinum beginning in 1987 that continued TX «^ W^»^".' TampaimpaBayBay ^ V "f ^ \ >^ Galveston Bay at least through 199^. Researchers have hypothesized Chandeleur Sarasota Bt .%• "" Mula^orda Bay Islands Cltarlalle ftarboi the involvement of several factors in the initiation of the ^, San . inlonii) Ba\ Bi.\caynf Bay 7, Cuipifi Chiisti Bin die-off, but few have been investigated adequately'". hloncia Bm Buljin Say -V; FlorklT Y.c^ Beginning in 1V91, algal blooms and persistent high Laf^ijiHj Mtijiv Gulf uf Mcxic turbidity were widespread, accounting for further deterioration of seagrass meadows, such that between Tamaulipas a Alacranes 198^ and 199A Thalassia testudinum biomass declined RIa Lagarlos, Ltn^tlita ik Tainiuliua Chelem by 28 percent, Syringodium fitlforme by 88 percent and Celestun/^ Yucatan Peninsula Halodule wnghtii by 92 percent'^'. Campeche ^ " iM^una dc Tcnnin'i\ The seagrasses in the Big Bend of Florida 131 MEXICO Lacuna li- . llvaraM Veracnjz^ ' percent of all seagrasses in Florida! have experienced 100 200 300 Kilomelers Tabasco relatively little impact from poor water quality problems or scarring from boat usage. This is due to Map 22.1 their remoteness from population centers and the The Gulf of Mexico relatively low population density of the area. However, the area is on the brink of a huge development effort. It beds'". These observed increases are believed to be can only be hoped that the state and local jurisdictions directly linked to improving water quality and light will demand proper sewage disposal (not septic tanks! penetration resulting from reductions in point-source and will not engage in the dredge and fill activities that pollutant loads. occurred in Tampa Bay and Sarasota Bay in the 1950s and 1960s. Alabama

Historical analysis is limited to only a few bay Alabama has only 90 km of exposure to the Gulf of systems along the west coast of Florida. Charlotte Mexico, and much of that is encompassed by Mobile

Harbor lost approximately 30 percent of its seagrasses Bay which receives river discharge volumes second prior to the 1980s'". There was a further harbor-wide only to the Mississippi River along the US portion of the decline of 3.3 percent 12.^3 km'] between 1988 and Gulf of Mexico. Consequently, there is little opportunity

1992. In 1992, the Southwest Florida Water Manage- for the establishment of true seagrass beds. A few ment District initiated a biennial mapping project to small patches of Haiodule wrigfitii have been reported assess trends in Charlotte Harbor Data from these at the south end of Mobile Bay along the western shore, studies will be used to assess the effectiveness of and 2.5 km' are present in Perdido Bay, shared with pollutant load reduction strategies on water quality. Florida, down from 4.9 km' in 1940-41"^'. At the west

Between 1992 and 199^, a 4 percent (2.91 km'] increase end of the Alabama coast and shared with Mississippi, was observed in the seagrass beds of the harbor, ephemeral beds of Ruppia maritima cover ca 2 km' in followed by an additional 3.6 percent increase (2.7A Grand Bay during the late spring and early summer, km'! between 199A and 1996. and Halodule wrightii has a[so been documented in this

Prior to the 1980s, seagrass losses in Sarasota area.

Bay were estimated to total approximately 30 percent.

However, changes in seagrass coverage in Sarasota Mississippi

Bay have been dramatic since 1988. Between 1989 and Historically, populations of Halodule wrightii, Halophila 1990, nitrogen loads to the bay from wastewater engelmanni, Ruppia maritima, Syringodium filiforme treatment plants diminished by as much as 25 percent. and Thalassia testudinum were present and abundant

Water transparency off the city of Sarasota and along the northern shores of Mississippi's barrier

Manatee County increased from a mean Secchi disc islands""^'". Overall, Mississippi has lost most of the depth of 1.1 m to 1.5 m, often deeper. Between 1988 and seagrass cover that was present in 1967-69, and only

199^, seagrass coverage in Manatee County increased one marine species, Halodule wrightii, still exists in

6.4 percent (1.'*2 km'l and another 7.8 percent 11.85 measurable quantities in Mississippi Sound. Ruppia km'l between 1994 and 1996. In Sarasota County, maritima (widgeon grass! occurs in isolated but well- seagrass coverage increased 10.1 percent 10.78 km'! developed patches along the immediate coastline, and between 1988 and 1994, and 22.7 percent (1.93 km'! as an occasional component in Halodule wrightii beds between 1994 and 1996. Most of these increases were along the barrier islands in Mississippi Sound. along the deep (>1.0 m! edges of existing seagrass Some well-established populations of Halodule 226 WORLD ATLAS OF SEAGRASSES

wrightii, Halophila engelmanni, Ruppia mantima. Mexico estuarme inventory"" were used as a historical Syringodium filiforme and Thalassia testudinum exist baseline, while data from a 1992 US Geological Survey

along the western shorelines and in the small internal aerial imagery study"" were ground-truthed to

bayou systems of the Chandeleur Islands, in south- document recent distribution patterns. Potential eastern Louisiana. These islands begin 37 km due south seagrass habitat was also identified using a 2 m critical

of Biloxi, and are a likely source of vegetative propagules depth limit which had been previously established in a and possibly seeds supplementing or repopulating National Park Service seagrass monitoring project"".

seagrass beds in some areas of the Mississippi coast. Seagrasses and potential seagrass habitat in

Seagrass distributions from a 1967-69 Gulf of Mississippi Sound lie mainly along the northern shorelines of the offshore islands. From east to west, Petit Bois Island supported 6.8 km' of seagrass Case Study 22.1 meadow according to the 1969 survey, down to 1.5 km' TAMPA BAY in 1992; Horn Island seagrass cover decreased from 22.5 km' to 2.2 km' over the same period; Dog Keys Based on the available habitat at that lime. Pass beds from 8.4 km' to none; Ship Island from 6.2

Tampa Bay is estimated to have supported km' to 1.0 km'; and Cat Island from 2.4 km' to 0.7 km'.

309.6 km' of seagrasses in 1879'". By 1981, only Only on T-shaped Cat Island do seagrass beds occur in

57.5 km' remained. The most dramatic decrease protected areas along its southwest shoreline as well

occurred between 1950 and 1963, when approxi- as along its north side. Ruppia maritima occurs at two

mately 50 percent of the total seagrass cover locations at opposite ends of the mainland shore: Point

disappeared. During this period. Hillsborough aux Chenes Bay at the Alabama border - 5.3 km' in

Bay lost 94 percent of its grass beds, Old Tampa 1969 down to 0.5 km' in 1992, and Buccaneer State

Bay lost AS percent and Tampa Bay proper lost Park, 10 km from the Louisiana border - 0.8 km' in

35 percent" "r 1969 down to 0.2 km' in 1992.

The losses up to the 1950s were due to State-wide in 1969 submersed aquatic vascular poorly treated wastewater discharges and plants covered an estimated 55.2 km' of coastal waters, industrial wastes from phosphate mines, citrus mostly true seagrasses on the north sides of offshore

canneries and other industrial sources""', as well islands. In 1992, only 8.1 km' of submersed vascular

as extensive dredging, and dredge and fill plants were found, 2.1 km' of which were from areas

activities that changed water circulation patterns not included in the 1967-69 survey"". Almost all of the

and caused extensive turbidity in the waters"". 2.1 km' were located in Grand Bay and are shared with

Recent work has shown that the trend of Alabama, as noted in the Alabama section. Therefore,

seagrass loss in Tampa Bay has been reversed seagrasses in Mississippi suffered a decline of between

In 1988, 93.1 km' of seagrass were present Ithis 85 and 89 percent over 23 years. Information from the

was the first year of monitoring conducted by early survey"" indicated that 67.6 percent of potential

the Southwest Florida Water Management seagrass habitat was vegetated, in comparison to only

District]"'. In 1990, this coverage increased 13.4 percent in 1992. Physical loss of seagrass habitat

to 99.3 km', and increased again in 199i to is assumed for areas where 1969 coverage exceeds

105.7 km'. The bay-wide seagrass coverage current estimates of seagrass habitat. This total is

in 1997 was estimated at 109.3 km'"". In estimated to be 19.6 percent. Since the discrimination

Hillsborough Bay, seagrass increased from near of seagrasses from macroalgae in the 1967-69 survey

zero in 1984 to about 0.57 km' in 1998. was less precise than in the 1992 assessment, losses

This expansion apparently started in may be somewhat overestimated.

response to water quality improvements from In Mississippi Sound, seagrasses appear to be

the late 1970s to the mid-1980s. These threatened by the cumulative effects of both natural

improvements followed a nearly 50 percent events and anthropogenic activities in the coastal

reduction in the early 1980s in external nitrogen marine environment. The primary vector for the

loading from domestic and industrial point disappearance of seagrasses is presently thought to be

sources, primarily discharging to Hillsborough an overall decline in water quality. Development may be

Bay. A slight decline in seagrass coverage a major factor, as it often results in elevated nutrient

occurred in Tampa Bay in the late 1990s, levels, higher sediment loads, and the introduction of

presumably a result of high rainfall during 1995, contaminants, which lead to a loss of water quality.

1996 and the 1997-98 El Nino event, all of which Cyclic shifts in precipitation patterns that affect both

increased nitrogen loading to the bay"". salinity and turbidity, and extreme events, especially

hurricanes, are also involved. Areas of seagrass habitat The Gulf of Mexico 227

loss coincide with areas where rapid coastal erosion""' north. Thaiassia testudinum is present at one location and massive long-term movement of sand have been at the extreme west end of the Galveston Bay system documented''"'. Physical loss of habitat and decreased and then is next seen 200 km to the southwest, where,

light availability in combination with declining water within 10 km of the gulf outlet at Aransas Pass, It is the quality are the most visible features that directly affect dominant species over a quarter of the vegetated seagrass communities. bottom. The association of Thalassia testudinum w'itU a

natural gulf outlet is even stronger In Laguna Madre.

Louisiana Within 20 km of Brazos Santiago Pass at the south end

The coast of Louisiana features a wide band of fresh to of the lagoon, Thalassia testudinum is the dominant , with some large lakes. Extensive beds species over 90 percent of the seagrass meadow. of submersed aquatic vascular plants occur there, but Farther from the outlet, Thalassia testudinum Is the salinity Is generally too low for seagrasses to thrive. uncommon. Syringodium filiforme occurs only south

Since the mid-1950s, seagrasses have been lost from from Aransas Bay near Aransas Pass and Is uncommon

Lake Pontchartrain and White, Calcasieu and Sabine in Aransas and Corpus ChristI Bays. It is the dominant

Lakes and from behind the south coast barrier species over 7 percent of the vegetated bottom In upper

Islands""". Small amounts of Halodute wrightii have Laguna Madre and 30 percent of vegetated bottom in reappeared on sand flats along the north shore, and lower Laguna Madre. still smaller amounts along the southeastern shore of Precipitation, inflow of freshwater and bathy- Lake Pontchartrain in the 1V90s. However, most of metry are the most influential environmental Louisiana's seagrasses are confined to the mixed determinants of the gradient of Increasing seagrass species beds along the western shore of the abundance from northeast to southwest along the Chandeleur Islands. The beds are relatively stable, at Texas coast. The much higher precipitation and inflow least by regional standards, only decreasing from of the upper Texas coast ensure that Its estuaries 6A.1 km' In 1978to 56.6 km'in 1989 despite the passage receive higher loads of sediments and nutrients and of two hurricanes In that period. Apparently, the islands greater freshening of bay waters than do estuaries of provide a protected shallow-water environment far the middle or lower Texas coast. This tends to result In enough removed from the plume of the Mississippi higher turbidity and a reduced area of suitable salinity

River and other influences of developed coastlines tor for seagrass growth. In addition Laguna Madre Is the seagrasses to thrive In the middle of an otherwise shallowest Texas bay so that sufficient light to support Inhospitable shore. seagrass growth reaches much more of the bottom

than in other bays. Texas The Galveston Bay system supported more than

Based on a recent compilation of surveys from the late 20 km' of submersed aquatic vegetation In 1956, but by 1980s and 1990s''", the coast of Texas supports 951 km' 1987 only 4.5 km'' remained'""". Seagrasses were of seagrass meadow. Unlike Florida, seagrasses in limited to West Bay and Its tributary embayment,

Texas do not occur seaward of the barrier islands and Christmas Bay, which Is furthest removed from riverine along the open coast. Rather, they are confined to the Influences. In West Bay, seagrass beds declined from more protected waters of the bays behind the barrier A.6 km' in 1956 to 1.3 km' In 1965 and were absent in

Islands, especially in the lagoonal segments extending 1987. In Christmas Bay the 5.0 km' of seagrasses In away from river mouths. Seagrasses are limited In 1971-72 declined to 1.1 km' in 1987. Losses are occurrence along the upper Texas coast to 16.6 km' In attributed to shorefront development and lower water

Galveston and Matagorda Bays, covering less than 1 quality associated with the urbanization of the area. percent of the bottom. Along the middle Texas coast, Including discharges of six sewage treatment plants, including the San Antonio, Aransas-Copano and Corpus two of which have been discharging since the early

ChristI Bay systems, cover by seagrasses increases by 1960s. In the mam stem of Galveston Bay extensive an order of magnitude (17^.8 km' and 12 percent of bay beds of Ruppia maritima present along the western bottom]. Along the lower Texas coast, encompassing shore In 1956 were destroyed by Hurricane Carta in upper and lower Laguna Madre and , 1961 and have not recovered, whereas beds In Trinity seagrasses define the ecosystem, covering 751.9 km' Bay have changed little. Reduced water clarity and and 50 percent of bay bottom. In Laguna Madre proper, subsidence resulting from excessive groundwater seagrasses carpet more than 70 percent of bay bottom. withdrawal coupled with bulkheading of the western

Haiodule wrightii is the dominant seagrass and shore of Galveston Bay may be responsible for the Haiophiia engelmanni and Ruppia maritima are at least failure of submersed vegetation to re-establish. The sporadically present In all bay systems along the Texas appearance of some patches of Haiophiia engelmanni coast. Ruppia maritima can dominate some beds in the in West Bay since 2000 may be an early indication that 228 WORLD ATLAS OF SEAGRASSES

Case Study 22.2 expense of Halodule wrightii which covered 67 LAGUNA MADRE percent of lagoon bottom in the earliest survey, and then declined to 41 percent at present. The loss of

Laguna Madre accounts for 75 percent of seagrass Halodule wrightii may have serious consequences

cover in the state of Texas, while making up only 20 because it is almost the sole food source for 400 000-

percent of the state's embayment area. Seagrasses 600000 wintering redhead ducks. are the foundation of the Laguna Ivladre ecosystem.

As a result of the high-quality nursery habitat pro- WATERWAYS PROMINENT ROLE vided by large expanses of continuous meadovi/. The Gulf Intracoastal Waterway plays a prominent Laguna Madre supports more than 50 percent of the role in most of the radical change seen in Laguna

Texas inshore finfish catch. Together with its sister Madres seagrass meadows over the last 35 years.

lagoon, the Laguna Madre of Tamaulipas, which lies The loss of seagrass cover in deep parts of lower

across the delta of the Rio Grande in Mexico, the Laguna Madre between 1965 and 1974, and its failure

area is even more important for the redhead duck, to revegetate since, is probably due to maintenance Aythya amencana. providing wintering habitat for dredging of the Gulf Intracoastal Waterway Intensive more than 75 percent of the world population. monitoring of the light regime before, during, and up

As a result of the importance of Laguna Madre to 15 months after maintenance dredging in 1988 as a natural resource, whole system seagrass surveys documented significantly increased light attenuation have been conducted at approximately decade to the end of the study in the region where sea-

intervals since the mid-1960s. Although seagrasses grasses had been lost. Laguna Madre is a notoriously strongly dominate the Laguna Madre ecosystem, they windy location and frequent episodes in which

have been undergoing profound change. In lower sediment from the mounds of unconsolidated, fine-

Laguna Madre seagrasses covered almost the entire textured dredge deposits is resuspended and dis-

bottom in 1965, but between 1965 and 197i large persed by currents account for the propagation of

tracts of deep bottom went bare and, with small dredging effects over large areas and long periods of

adjustments in configuration, have remained bare to time. Since dredging frequency is in the order of two

the present day Shifts in species composition have years, the light reduction is chronic™. been even more far reaching, with Halodule wrightii The Gulf Intracoastal Waterway is also

dominant over 89 percent of the seagrass meadow in implicated in the other big change in seagrasses in

1965 and only 41 percent in 1998-99, being replaced lower Laguna Madre, the displacement of Halodule by other species from the south. Syringodium wrightii by more euhaline (adapted narrowly to

fiiiforme achieved maximal coverage in the 1988 marine salinity! species moving north overtime. Prior

survey but already was being replaced in the south by to completion of the Gulf Intracoastal Waterway in Thatassia testudinum. By the 1998-99 survey this 1949, there was no permanent water connection displacement was much farther advanced. Halophila between upper Laguna Madre and lower Laguna

engelmanni is a transient in this system, occupying a Madre. A 30 km reach of seldom flooded sand flats

considerable area at the outer edge in the 1 988 survey prevented this. Before 1949, salinities in excess of 60

but not dominant at any other time. In upper Laguna psu, or about twice the salt content of the adjacent

Madre, between 1967 Isee figure, opposite! and 1988 Gulf of Mexico, were not uncommon in lower Laguna

(not shown], cover of Halodule wrightii mcreased from Madre, and in the southern extremity of upper Laguna

118 to 2i9 km' and was continuous from shore to Madre salinities in excess of 100 psu were measured

shore over the northern third of the lagoon. However, several times. The breaching of the sand flat barrier

by 1998-99 Halodule wrightii cover had decreased to at the midpoint of the lagoon greatly enhanced

214 km^ with a central deep area in the north exchange within the lagoon and between the lagoon

reverting to bare bottom and a large patch of and the Gulf of Mexico. Prevailing southeasterly winds

Syringodium fiiiforme taking over at the north end. now drive lagoon water north across Corpus Christi

From the mid-1960s to the present, for the Bay and ultimately out into the gulf, with inflow from

lagoon as a whole, the area of bare bottom has the gulf at the south end replenishing the system. The increased by 10 percent. The area of Thalassia net result was a moderation of hypersaline conditions

testudinum has increased from barely present to within the lagoon. Now, salinities seldom reach

dominating some 11 percent of lagoon bottom. 50 psu anywhere in the lagoon.

Syringodium fiiiforme increased from 7 to 17 Halodule wrightii is the only species that can

percent, and then fell back to 15 percent, all at the tolerate salinities greater than 60 psu and is a The Gulf of Mexico 229

superior colonizer compared to Syringodium filiforme tide". The bloom varied in intensity but was or Thatassia testudlnum. Consequently, Halodule continually present from 1990 to 1997 and has flared wrightii was probably widespread before construction up sporadically since. Light intensity at 1 m depth of tine waterway, although there are only incidental was reduced by half over large areas, and gradually reports from a few locations for that period, and it is Halodule wrigfitii died back in deep areas. Although not surprising that according to the first systematic a suite of factors played a role in the initiation and survey of seagrass cover in the mid-1960s it unprecedented persistence of the brown tide, dominated the lower Laguna Madre overwhelmingly nutrients regenerated from the gradual die-back of Gradual displacement from the south by Syringodium the seagrass meadow were almost certainly involved filiforme, in its turn later displaced by Thalassia in sustaining the bloom, until steady state was testudinum, is consistent with what we know of the reached between seagrass distribution and the relative salinity tolerances of the species, and their brown tide-influenced light regime. A disturbing colonizing and competitive abilities under conditions aspect of this perturbation is that as yet there is little of moderate salinity The euhaline species had been sign of recovery. Apparently because of the loss of confined to the immediate vicinity of the natural gulf seagrass cover, the bottom is much more prone to outlet at the extreme south end of the lagoon until sediment resuspension. Because new recruits have moderation of the salinity regime. Thereafter, life no reserves to tide them over episodes of low light, history and competitive characteristics of the plants establishment has not occurred'"'. set the time course of change'"'.

THE UPPER LAGUNA MADRE Presumably, upper Laguna Madre has experienced the same system shift as lower Laguna Madre, yet its trajectory of seagrass change has been very different. Halodule wrightii increased rather than decreased through 1988 and Syringodium filiforme was not evident until 1998-99. Changes in upper

Laguna Madre seem to lag those in lower Laguna Madre by 20 or 30 years. Almost certainly, the reason for the lag is the extreme hypersalinity of the southern section of upper Laguna Madre before completion of the waterway Even Halodule wrightii cannot tolerate 100 psu salinity and must have been absent from most of upper Laguna Madre, except close to Corpus Christi Bay The much greater

distance to source populations probably accounts for

expansion of Halodule wngfitii meadows through

1988 in the upper Laguna Madre, whereas it was

already at a maximum in the lower Laguna Madre by 1965. Similarly, the possible sources of Syringodium

filiforme for the colonization of upper Laguna Madre are the lower Laguna Madre or across Corpus Christi Bay, near the closest gulf outlet to the north.

Not surprisingly, establishment in upper Laguna

Madre was long delayed compared to lower Laguna

Madre, where it was present from the outset.

The last large historical change is the loss of vegetation from deep parts of upper Laguna Madre between 1988 and the present. Through 1990,

Laguna Madre was renowned for its crystal clear Seagrass cover in tfie Laguna Madre of Texas

water However, in June 1990, a phytoplankton

bloom was first noted that was dense and long-lived Notes: Halodule wnghtii [greeni, Synngodium filiforme Igreyl,

enough to earn it its own name, the "Texas brown Tfialassia testudinum Iblackl, bare/no seagrass Ivi/hitel. 230 WORLD ATLAS OF SEAGRASSES

management efforts are resulting in improved water engelmanni and Halophila decipiens. Halodule wrightii

it tolerates quality in the bay. is found in the shallower areas where

Little net change in seagrass cover is evident changes in temperature and salinity, and Halophila along the middle Texas coast'^". The dredging of decipiens is found in the deeper parts down to 10 m. navigation channels, boating activities and nutrient Other species associated with the Thalassia enrichment from non-point sources are the suspected testudinum here include green, brown and red

causes of a loss of 3.3 km^ of Thalassia near Aransas macroalgae, foraminifers, sponges, anemones, corals,

Pass, while in the same general area, subsidence has polychaetes. mollusks, crustaceans, sea urchins, sea 1977'"" led to inundation of previously emergent flats and stars and fish""'. First identified in and colonization of 8.7 l

absence of bulkheading in this part of Corpus Christi, environmental problems in this area are caused by the effect of subsidence on submersed vegetation is the local fisheries as well as by the great loads of sediment, and herbicides that are opposite of what it was with bulkheading in Galveston fertilizers, insecticides Bay. A growing management concern along this part of transported along the coastal rivers to the coral reefs during the coast is that large areas of shallow seagrass and seagrass beds, only to be resuspended meadow close to population centers show moderate to winter storm seasons. heavy propeller scarring'"'. The waters of Laguna de Tamiahua are predominantly euhaline because the lagoon has only MEXICO two small sea inlets at the north and south ends and The southwestern coast of the Gulf of Mexico has freshwater inflow is limited to several very small approximately 15 estuarine systems. The largest creeks. The western margin has extensive beds of

include Laguna Madre 12 000 km'] in the state of macroalgae while Halodule wrightii is established Tamaulipas, Laguna de Tamiahua 1880 km') and along the eastern margin of the lagoon and covers

Laguna de Alvarado 1118.3 km"! in the state of Veracruz, 106.2 km' or 12 percent of the lagoon area. Associated and Laguna de Terminos 11700 km] in the state of macrofauna includes 67 species of mollusks. 32 of Campeche. The study of seagrasses and their crustaceans and 129 of fish"".

distribution in Mexico dates from the 1950s. In the By contrast Laguna de Alvarado has two sea

southwestern Gulf of Mexico there are five genera of inlets, one of which is a narrow channel, and four seagrasses: Thalassia. Syringodium. Halodule, Halo- rivers, one of which carries a great volume of water phila and Ruppia, of which Thalassia has the widest Consequently, the lagoon is oligo-mesohaline with throughout the greater part of distribution. It is found from Tamaulipas in the north to salinities below 18 psu percent Quintana Roo in the south as well as in various reef the yean Ruppia mantima covers 3.2 km' or 3 systems'™'. of the lagoon area. This is the only species of seagrass

in Alvarado where it forms dense beds along the inner Tamaulipas margin of the sand barrier. Associated macrofauna The seagrass species reported for this coast include includes 49 species of mollusks, 26 of crustaceans and Thalassia testudinum, Syringodium filiforme. Halodule 106 of fish"". wrightii and Halophila engelmanni. Laguna Madre has

four inlets that change position over time. As a result of Tabasco of its location in a semi-arid area, its restricted Very little is known about seagrasses in the state communication with the sea and a minimum river Tabasco. Only Halodule wrightii and Ruppia maritima runoff from the San Fernando river, this lagoon is have been recorded for the coastal lagoons with a cover hypersaline, with marine conditions restricted to the of 8.1 km'. The scarcity of seagrasses along the coast is

areas of tidal influence near the inlets. The western the result of the large sediment load and high turbidity margin has extensive beds of macroalgae, while delivered by the Grijalva-Usumacinta river system and

Halodule wrightii is established along both the eastern transported west along the coast. and western margins of the lagoon and covers 357.4 km' or 18 percent of the lagoon area. Associated Yucatan Peninsula macrofauna includes 76 species of mollusks, 42 of The Yucatan Peninsula is located in the southeastern

crustaceans and 105 of fish'"'. Gulf of Mexico, includes the states of Campeche, Yucatan and Quintana Roo, and encompasses islands. Veracruz approximately 1 800 km of coastline, including

The system of coral reefs in front of the port of Veracruz The karstic nature of the peninsula is responsible for

boasts five seagrass species: Halodule wrightii, non-point groundwater discharges through springs Thalassia testudinum, Syringodium filiforme, Halophila directly into coastal lagoons, the broad continental

I Regional map: The Caribbean XIII XIV Regional map: South America

70° -^ 55° 40° CARIBBEAN SEA * • N .®^- •• w ^ ATLANTIC OCEAN

5° 5° T^ ^t

:- " ^ ~N^- '^m .

r f 10° 10°

• •*

4 •

'"J ^ 1 a

,_^-'^-V~< ..'*'''' 25° 25° "oI PACIFIC OCEAN ® i^^^^^^^^^^^^^^^^^^^^^K, n ii 40° 40°

W ATLANTIC R OCEAN 4\

55° 55°

\ JSai JUU p 300 600 900 1200 1500 km

85° 70° 55° 40° 25° The Gulf of Mexico 231

shelf and the open sea. Based on satellite images and testudinum and Syringodium filiforme have also been field observations during 2000-01, there are 5911 km' sighted around the reefs of Alacranes and Cayo Areas, of seagrasses"" in the coastal lagoons, the coastal sea Campeche. and the coral reef lagoons of Chinchorro and Thalassia testudinum is dominant in open waters,

Alacranes. especially in the coral reef lagoons. The maximum total

Seagrasses along the coasts of the peninsula biomass and shoot density recorded are 2000 g/m' and """. include the six species present in the southwestern 1 222 shoots/m' Halodule wrightii is the most

Gulf of Mexico. The most widespread species are widely distributed species in the peninsula. It is found in

Thalassia testudinum, Syringodium filiforme and mixed and monospecific stands, in shallow waters

Halodule wnghtii, with this last species also found in l<1 ml, around freshwater springs and at salinities the hypersaline Ria Lagartos, Yucatan. Halophiia between 20 and 57 psu. The maximum total biomass engelmanni and Halophila decipiens are found in and shoot density recorded are 700 g/m'^ and H872 small areas while Ruppia mantima is found in the shoots/m""**'". Syringodium filiforme has been obser- shallow brackish coastal lagoons of Terminos, ved mainly in open waters mixed with l-lalodule wrightii

Celestun, Chelem, Dzilam, Ria Lagartos, Nichupte, and Thalassia testudinum. dominating in regions where Ascension and Chetumal'"'. Beds of Thalassia strong currents are observed. The maximum total

Case Study 22.3 part as nursery, feeding and protection areas for the LAGUNADE TERMINOS larvae and juveniles of commercially important species, such as the shrimp Litopenaeus setiferus,

Laguna de Terminos is the best studied coastal Farfantepenaeus aztecus and Farfantepenaeus

lagoon in the Mexican Gulf of Mexico. It is located at duorarum, and the fish Caranx hippos, Lutjanus the transition area between a western terrigenous analis, Bagre marinus, Centropomus undecimalis

region and an eastern calcareous region and is also and Archosargus rhomboidalis, that migrate

characterized by a marked north-south salinity through the lagoon during their life cycles and con- gradient, established by the tides that enter through stitute offshore fisheries of great economic value,

two sea inlets and the freshwater provided by three among which the shrimp fishery is particularly rivers"". The seagrasses Thalassia testudinum, noteworthy

Syringodium filiforme and Halodule wrightii cover Associated macrofauna include 174 species of

496.4 km' or 29 percent of the lagoon area mollusks. 60 of crustaceans and 214 of fish'"', Thalassia testudinum covers extensive areas establishing Laguna de Terminos as the most

along the northern, eastern and southeastern species rich (4481 of Mexico's four large lagoons

margins where salinity is high and the water is along the Gulf of Mexico, supporting almost twice as

relatively clear, creating an ideal environment for many species as the other lagoons (181 species in

this tropical, polyeuhaline species'"'. Syringodium Laguna de Alvarado, 228 species in Laguna de

filiforme is restricted to the northeastern region Tamiahua and 223 species in Laguna Madrel. The

where salinity is high and the sediment is biogenic, environmental heterogeneity and complexity of sandy and calcareous. This species favors calcar- Laguna de Terminos arise from the presence and

eous substrates and is found forming dense distribution of the four seagrass species, macro-

seagrass beds along the eastern Caribbean coast of algae, mangrove forests and the marked salinity

Mexico, l-lalodule wrightii is found along the north- gradient, all of which favor the recruitment of a great

ern and western margins of the lagoon, the first with number of stenohaline and euryhaline estuarine

high salinity, clear water and sandy substrates, and species, and some marine species. These establish

the second with low salinity, turbid water and muddy communities with different trophic structures'"' substrates, where the great Grijalva-Usumacinta subdividing the lagoon according to their

river system drains into the lagoon. Its distribution preferences for different habitat types'"'.

shows it is a tropical euryhaline, pioneering and No long-term data on seagrass coverage have adaptable species that tolerates a variety of been recorded for Laguna de Terminos. However, environmental characteristics. Ruppia mantima has the extent of the seagrass beds, as well as shoot

also been observed in the low-salinity areas of the density, along the inner margin of the barrier island southwest of the lagoon. were markedly reduced when Hurricane Roxanne

In this lagoon, all seagrass beds, but mainly passed over the lagoon twice in October 1996.

those of Thalassia testudinum, play an important Recovery occurred within three years. 232 WORLD ATLAS OF SEAGRASSES

biomass and shoot density recorded are 1 000 g/m' and hydrological restoration took place and the seagrass 7U0 shoots/m^''"'. Halophila decipiens and Halophila community recovered'"". Natural events such as

engetmanni can be observed in small patches mixed hurricanes have significant effects on seagrass

with other seagrasses and macroalgae in Yucatan and communities. However, these have shown an important Quintana Roo, mainly on shallow (<1-5ml sandy recovery capacity. For example, during Hurricane

bottoms. Ruppia maritima has been observed growing Gilbert in 1988, Halodule wnghtii beds in the coastal

in mixed stands with Halodute wnghtii in polyhallne |18 lagoon of Celestun, Yucatan, lost 93 percent of their

psul waters, and in monospecific stands in mesohallne area. Within three years, they had recovered to their

15-18 psul waters with a biomass of 1 000 g/m\ initial condition'"'. A similar pattern of recovery was

The seagrasses of the peninsula have been observed for Thalassia testudinum In Canciin""'.

affected by trawling and eutrophlcatlon In Campeche, by trawling, tourism, eutrophlcation and port development CONCLUSION

in Yucatan, and by tourism and eutrophlcation in The Gulf of Mexico is a globally important seagrass

Quintana Roo, all suggesting that water quality Is a area. Extensive beds cover about 19000 km^ from Cuba

major concern for the seagrasses In this region. and the southern tip of Florida through Texas to the

Historical analysis is limited. Observations from Yucatan Peninsula of Mexico. In many places Impacts

1985 to 2001 In Progreso, Yucatan, show a loss of 95 appear to be low and seagrass beds healthy; however,

percent of seagrass cover and a replacement by green some recent perturbations are disturbing because of

macroalgae [Cauierpa spp.l, with eutrophication again their magnitude and our inadequate understanding of

the main cause'"'. However not all decline has proved causation. Most worrisome are the persistent and

permanent. Following the construction of port recurring algal blooms, high turbidity and changes in

infrastructure in the north of Yucatan the hydrology of species composition afflicting seagrass meadows of the Chelem Lagoon changed and the seagrass Florida Bay on the east side and Laguna Madre on the community was negatively impacted. Four years later west side of the Gulf of Mexico.

AUTHORS -

Christopfier P. Onuf, US Geological Survey, National Wetlands Research

Center, Campus Box 339, 6300 Ocean Dnve, Corpus Christi, Texas, USA.

Tel: +1 361 985 6266. Fax: +1 361 985 6268. E-mail: chns.onufrausgs.gov

Ronald C. Phillips, 3100 South Kinney Road #77, Tucson, Arizona 85713,

USA. -'. *jM^^»

Cynthia A. Moncreiff, Gulf Coast Research Lab, RO. Box 7000, 703 East

Beach Drive, Ocean Spnngs, Mississippi, USA. ^..m

Andrea Raz-Guzman, Institulo de investigaciones sobre los Recursos

Naturales, Universidad Michoacana de San Nicolas de Hidalgo, Avenida

San Juanito s/n, San Juanito Itzicuaro. Morelia 58330. Michoacan, Mexico.

Jorge A. Herrera-Silveira, CINVESTAV-IPN. Merida, Cam Ant. Progreso

Ray on low-density Syringodium lililorme. Mexican Caribbean. km 6, Menda 97310, Yucatan, Mexico.

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The Gulf of Mexico 233

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10 Johansson JOR, Lewis RR 111 [1991]. Recent improvennenis in water pp 233-245.

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85(7.181. de Veracruz, Ver Anales del Instituto de Biologia Sena Botanica

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Bay: A resource-based approach to estuarine management. In: 31 http://www.dumac.org.mx

Bortone SA led! Seagrasses: Monitoring, Ecology, Ptiysioiogy and 32 Espinoza J [1996]. Distribution of seagrasses in the Yucatan Management. CRC Press, Boca Raton, FL. pp 279-293. Peninsula, Mexico. Bulletin of Marine Science 59: 449-454.

13 Handley LR [1995]. Seagrass distributions in the northern Gulf of 33 Gallegos ME, Merino M, Marba N, Duarte CM [1993]. Biomass and

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Service, Washington, DC. pp 273-275. growth of the turtle grass Thalassia testudinum [Banks and Konig)

14 Eleuterius L N [1973]. The distribution of certain submerged plants in a shallow tropical lagoon system in relation to tourist

in Mississippi Sound and adjacent waters. In: Christmas JY (edl development. Caribbean Journal of Science 32: 357-364.

Cooperative Gulf of Mexico Estuarine Inventory and Study 35 Herrera-Silveira JA [1994]. Phytoplankton productivity and

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Research Laboratory, Ocean Springs, MS. pp 191-197. lagoon with groundwater discharge. Vie Milieu 44: 257-266.

15 Eleuterius LN, Miller GJ [1976]. Observations on seagrasses and 36 Gallegos ME, Merino M, Rodriguez A, Marba N, Duarte CM [19941.

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the Mississippi Academy of Sciences 21 : 58-63. Halodule wrightii and Syringodium filiforme. Marine Ecology

16 Sullivan MJ [1979]. Epiphytic diatoms of three seagrass species in Progress Series W:99-m.

Mississippi Sound. Bulletin of Marine Science 29: 459-464. 37 Herrera-Silveira JA, Troccoli, GL, Aranda CN, Alvarez GC, Trejo J

17 US Geological Survey (19921. Draft maps: Isle au Pitre, LA-MS, Cat (2000]. Evaluacion de la calidad ambiental de la zona costera de

Island, MS-LA, Ship Island, Dog Keys Pass, MS, Horn Island West, Progreso: Hidrologia y clorofila-a. Informe Tecnico CINVESTAV-

MS, Horn Island East, MS, Petit Bois Island, MS, Grand Bay SW, LPP, p 50.

MS-AL, Kreole, MS-AL. Scale 1:24 000. National Wetlands 38 Herrera-Silveira JA, Ramirez-Ramirez J, Gomez N, Zaldivar A

Research Center, Lafayette. LA, (2000]. Seagrass bed recovery after hydrological restoration in a

18 Heck KL, Sullivan MJ, Zande JM, Moncreiff CA [1996]. An Ecological coastal lagoon with groundwater discharges in the north of

Analysis of Seagrass Meadows of the Gulf Islands National Yucatan. In: Bortone S led] Seagrass: Monitoring Ecology, Seashore, Years One, Two, and Three: Seasonal assessment and Physiology and Management. CRC Press, Boca Raton, FL. inventory, interaction studies and continuing assessment/inventory, pp 123-135. August 1996. Final Report to the National Park Service. 39 Herrera-Silveira JA [19931. Ecologia de los productores primarios

19 Oivanki SM [1994]. Belle Fontaine, Jackson County, Mississippi: en la laguna de Celestun, Mexico. Patrones de variacion espacial y Human history, geology, and shoreline erosion. Mississippi temporaL Doctoral thesis. University of Barcelona.

Department of Environmental Quality. Office of Geology, Bulletin 40 Marba N, Gallegos ME, Merino M, Duarte CM [1994]. Vertical

No. 130. growth of Thalassia testudinum: Seasonal and interannual

20 Otvos EG (1981). Barrier Island formation through nearshore variability. Aquatic Botany il: 1-11.

aggradation: Stratigraphic and field evidence. Marine Geology iJ: 41 Raz-Guzman A, de la Lanza G [1991]. Evaluation of photosynthetic

195-243. pathways of vegetation, and of sources of sedimentary organic

21 Pulich W Jr (19991. Introduction. In: Seagrass Conservation Plan for matter through 6"C in Terminos Lagoon, Campeche, Mexico, Texas. Texas Parks and Wildlife Department, Resource Protection Anales del Instituto de Biologia Sena Botanica UHAM 62: 39-63,

Division, Austin, TX.pp 14-29. 42 Phillips RC (19801, Role of seagrasses in estuarine systems. In:

22 Pulich WJr, White WA (1991]. Declineof submerged vegetation in Fore PL, Peterson RD (edsl Proceedings Gulf of Mexico Coastal

the Galveston Bay system: Chronology and relationships to physical Ecosystems Workshop. US Fish and Wildlife Service, Albuquerque,

processes. Journal of Coastal Research 7: 1 125-1 138. New Mexico, FWS/OBS-80/30, pp 67-96, 23 Adair SE, Moore JL, Onuf CP [19941. Distribution and status of 43 Raz-Guzman A, Sanchez AJ [1996], Trophic structure related to

submerged vegetation in estuaries of the upper Texas coast. seagrass habitat complexity In: Kuo J, Phillips RC, Walker Dl,

tVef/snt/s 14: 110-121. Kirkman H (edsl Seagrass Biology. Proceedings of an International

24 Ounton KH, Schonberg SV [2002]. Assessment of propeller scarring Workshop. Rottnest Island, Western Australia. University of

in seagrass beds of the south Texas coast. Journal of Coastal Western Australia, Nedlands, Western Australia, pp 241-248.

Research Special Issue No. 37: 1 00-1 1 0. 44 Sanchez AJ, Raz-Guzman A [1997]. Distribution patterns of tropical

25 Onuf CP [1994]. Seagrasses, dredging and hght in Laguna Madre, estuarine brachyuran crabs in the Gulf of Mexico. Journal of Texas, USA. Estuarine Coastal and Shelf Science 39: 75-91. Crustacean Biology M: 609-620. 234 WORLD ATLAS OF SEAGRASSES

23 The seagrasses of THE CARIBBEAN

J.C. Creed

R.C. Phillips

B.I. Van Tussenbroek

Caribbean region includes the following resources. Substantial research is still needed in order Thesub-regions'": western Caribbean (Mexico. to provide a comprehensive assessment of Caribbean Belize. Guatemala and Honduras), southern seagrasses. Caribbean (Nicaragua. Costa Rica and Panama, and Seagrasses are found throughout the Caribbean. South American Colombia], the Lesser Antilles They grow in the reef lagoons between the beaches and (Venezuela, and the islands , Curacao, Bonaire. coral reefs or form extensive meadows in more Trinidad and Tobago. Barbados, Grenada, St Vincent protected bays and estuaries. Seven seagrass species and the Grenadines, St Lucia, Martinique, Dominica, are recognized. Turtle grass, Thalassia testudmum, is Guadeloupe, Antigua and Barbuda, Montserrat, St the most abundant seagrass in the region, but is not

Kitts and Nevis, St Martin (), St Eustarius, known south of Venezuela. Plants are erect, leaves , AnguiUa, the British Virgin Islands, Turks and generally varying from 5 to 15 mm wide and from 10 to

Caicos Islands, and the US Virgin Islands! and the 50 cm long, but can reach up to 1 m. This seagrass Greater Antilles (Puerto Rico, Hispaniola, Jamaica, the forms dense rhizome mats below the sediment

Cayman Islands and Cubal. In the wider Caribbean creating extensive meadows on shallow sand or mud context, here we also consider the Guyanas (Guyana, substrates from the lower intertidal to a maximum 10- and French Guianal. the Bahamas and the 12 m depth, but has also been reported below 20 m.

east coast of Florida. Manatee grass, Syringodium fiiiforme, has a similar The coastlines of the mainlands and islands geographical distribution, with cylindrical, narrow

under consideration stretch from about 26°N to A°S leaves which form canopies up to A5 cm high. It usually

and from 88°W to 52°W, and are influenced by the Gulf grows intermixed with Thalassia testudinum, but can

of Mexico, the Caribbean Sea and the Atlantic Ocean. grow in monospecific areas, beds or patches from the They stretch from the Tropic of Cancer (only the north- upper subtittoral down to more than 20 m. ern Bahamian islands and Florida are subtropical) to Shoal grass, Halodute wrightii, is found

just north of the equator throughout the wider Caribbean region. It has small,

In a review of seagrass ecosystems and resources supple, grass-like leaves varying in width between 2

of in 1992, Phillips'" stated that "the and 5 mm and in length between i and 10 cm, but

most basic research is needed in almost every place". sometimes reaching more than 50 cm in length. It is During the subsequent decade, the number of found growing on sand and mud from the intertidal published reports and surveys on the biology and down to 5 m. Ruppia mantima, widgeon grass, is also

ecology of the seagrasses of Central and South found throughout the Caribbean and, like Haiodule

America has increased. The seagrass communities of wrightii, has small grass-like leaves. It is a shallow-

some of the islands of the Bahamas, and the Greater water species found in the brackish waters of bays and and Lesser Antilles, have also been quite well studied, estuaries between and 2.5 m deep. The three sea vine but both quantitative and qualitative information on the species belonging to the genus Haiophila - Hatophita

status of seagrasses is highly variable, reflecting the baiUonii, Haiophila engelmanni and Haiophila

large number of countries and territories which make decipiens - are small and delicate. Their leaves are up the region and their individual political and paddle shaped, are less "grass-like" than the other economic approaches to research, as well as species and lack a basal sheath. Haiophila decipiens is

exploitation and protection of coastal marine found in deep water (to 30 ml, while Haiophila M W

The Caribbean 235

200 400 600 Kilomelefs coexists with Synngodium filiforme, Hatodule wnghtii

Indiun River Lif^ooii and calcareous rhizophytic green algae belonging to Schasiiaii Inlvl the order Caulerpales, amongst which Halimeda spp. ATLANTIC ^ Uxuma Cays are the most conspicuous members, and play an Puerto Morelos OCEAN IhxanoBaS'^. • Reel National Park ^', BAHAMAS important role in production of sediments. Calcium

carbonate sand production of Halimeda spp. in us AND UK PUERTO VIRGIN ISLANDS seagrass can exceed RICO beds 2 kg/m*7year'-'. Other non- HAITI ."VAmbergn^Cay ^^ ^ calcified rhizophytic algae of the same order such as •' '"t- Calabash Cay "l * "' „ Jamaica ' i i Caulerpa spp. and Avrainvillea spp. are also found in Jr~ ., Soulh WalCT Cay unCrviD.rS CIRISBEANSEA Pointe Sable • ^ these beds. Drifting or free-floating masses of algae National Park ParquG ^r le.g. Laurencia spp., Lobophora Natural Cum sp., Euchema sp., J' Tayrona Hypnea sp. and Acanthophora sp.l may be abundant Curlujiciia Bay^ Buhiu 1ms Minus locally. Thaiassia (estud/num-dominated communities " ' -i PanjuoNacfonsf ./.. , Mochmha in reef ) Mo/TOCOy environments are usually preceded on the beach "">' Lake Mamcaiho side by a small fringe of Halodule wnghtii. In deeper Galeta Pcwnt 80' waters, other seagrasses such as Synngodium Map 23.1 filiforme and Halophila decipiens replace Thaiassia The Caribbean testudinum.

In more protected areas, such as estuarine engelmanni is found only down to 5 m and is restricted environments, or zones influenced by mangroves, and to the Bahamas, Florida, the Greater Antilles and the depending on prevailing salinity, nutrient conditions, western Caribbean. Hatophila bailtonii is only found in light and sediment conditions, seagrass vegetation the Lesser Antilles'^'. consists of virtually monospecific beds or alternating monospecific patches of Thaiassia testudinum and ECOSYSTEM DESCRIPTION Halodule wnghtii with rhizophytic Caulerpa spp. and

The coastlines of the Caribbean are characterized by loosely attached green algae, many of which belong to three ecosystems: seagrasses, coral reefs and the order Dasycladales (e.g. Batophora sp., mangroves, with numerous linkages and trophic Acetabularia spp.l. Drifting mats, when occurring, are interactions existing between these ecosystems'"". typically formed of filamentous red and green algae in

Seagrasses are considered to be open systems, these areas. Ruppia maritima is found in brackish exporting leaves and other components of primary waters in bays and estuaries, sometimes with Halodule production m the form of organic material to other wnghtii. Halodule wrightii forms monospecific stands habitats. At Galeta Point, Caribbean Panama, a in lagoons with high salinity fluctuations. Halophila 0.01-km' seagrass bed has been estimated to export spp. grow in finer sands and sediments, forming 37-294 kg/month of Thaiassia testudinum leaves, and monospecific or mixed species beds with the above- 3-171 and 3-74 kg/month, respectively, of the mentioned seagrasses. Halophila spp. require less associated macroalgae Laurencia and Acanthophora light than the other seagrass species, and can be found spp. Seagrass and its associated algal material can in very deep waters or in very shallow areas with turbid even end up as offshore foodfalls, which have been conditions. shown to be a significant pathway by which energy Seagrasses are colonized by calcareous and enters the deep sea'". Seagrasses, by stabilizing filamentous epiphytes. In classic models of Caribbean sediments in their extensive systems of roots and seagrass succession, rooted vegetation starts with rhizomes, prevent abrasion and burial by sediments of rhizophytic algae followed by Halodule wrightii land the adjacent corals during storms. sometimes Syringodium filiforme] which are con- Migratory movements of various animals such as sidered to be pioneer species, with a Thaiassia fish, spiny lobsters, prawns and sea urchins enhance fesfud/nivm-dominated vegetation as climax" '". the links between the seagrasses, reefs and An enormous diversity of fauna is associated with mangroves. These migratory movements can occur on the Caribbean seagrasses. Groups that contribute most a daily basis le.g. foraging in the seagrass beds during to the richness of seagrass systems in the Caribbean the day and sheltering from predation in the reefs are fish, echinoderms, decapods, gastropods, mollusks during the nightl or seasonally, when juvenile stages of and sponges. Foraminifera, polychaetes, oligochaetes, species migrate from mangroves or seagrasses to the nematodes, coelenterates, amphipods, isopods, reefs when reaching adulthood'"". hydrozoans and bryozoans are important mesofaunal Thaiassia testudinum typically dominates groups. The Caribbean seagrasses have distinct seagrass vegetation in the reef lagoons where it often demersal fish assemblages. Fish assemblages in the 236 WORLD ATLAS OF SEAGRASSES

seagrasses vary depending on their affinity witfi blades, consuming 0.155 (Jamaica) and 1.^ (St Croix, mangrove and coral reef communities. At Martinique. US Virgin Islands] g dry weight/individual/day, French West Indies, 65 species of fishes belonging to 28 respectively, of Thaiassia testudinum. Diadema

families were collected in Thaiassia testudinum beds. antillarum is another important herbivorous urchin in

In lagoons, the fish community is some places. Leaves of seagrasses are used as a

dominated numerically and in biomass by grunts, substratum by invertebrates such as hydroids and apogonids and tetraodontitorms. Most fishes are either sponges. Foraminiforans play a large role in the

juveniles of species that occur as adults on the reef, or production of calcareous sediments.

are small species that reside in the lagoon. In Panama Two potentially important mesofaunal top-down and the Virgin Islands, juvenile snappers, scorpion regulators in Thaiassia testudinum beds are the

fishes, grunts and goatfishes in seagrass meadows isopod Limnoria simulata, which bores into the live feed predominantly on decapod crustaceans and other tissue of Thaiassia testudinum"', and the small green

fishes. snail Smaragdia viridens, which grazes on the

Macroinvertebrate diversity in seagrass beds is chloroplast-containing epidermis. Macroalgae in sea-

high; for example, in Venezuela, 1 27 macroinvertebrate grass beds can provide food and shelter for associated species are associated with the seagrass beds at fauna. The inconspicuous epiphytes are a major food Mochimba Bay'". Throughout the Caribbean, sea source to members of the mesofauna. The seagrass- urchins such as Lytechinus vanegatus and Tripneustes associated alga Batophora sp. is a preferred source of ventricosus are also major herbivores of seagrass food for the queen , and Laurencia spp. are the

Case Study 23.1 Florida's east coast, usually in mixed beds FLORIDA'S EAST COAST rather than pure stands: Thaiassia testudinum, Synngodium filiforme, Halodule wnghtii, l-lalophila

The seagrasses of Florida's east coast, from decipiens, Halophila engelmanni, Ruppia maritima

Mosquito Lagoon (29''N1 in the north to lower and Halophila johnsonii. The first six are also found

Biscayne Bay 125°N) south of Miami, occur in the throughout the Caribbean. Similar to its growth habit

shallow lagoonal coastal river systems typical of this in other areas. Thaiassia testudinum is a climax area. IThe seagrasses of the Florida Keys are species, slow growing, long lived and requiring high

covered in Chapter 22.1 Approximately 2800 km' of light levels. Thaiassia testudinum is more abundant

seagrass habitat is found along the east coast of in the south, reaching its northern limit in the mid-

Florida, much of it in the Indian River Lagoon. 250 Indian River Lagoon; beds often persist for decades. km long and encompassing population centers and Shoal grass. Halodule wrightii, is the most abundant many canal-side and manna-onented housing seagrass in the mam part of the Indian River Lagoon,

developments. Estimates of seagrass decline in- an early colonizer, and grows in both shallow and

clude a loss of about 30 percent from the Indian mid-depths Ito 2 ml, Synngodium filiforme is known

River and. since 1950, a 43 percent loss from the as "manatee grass" and is habitat and food for the

northern and urbanized section of Biscayne Bay manatee and the second-most commonly occurring

However, Indian River seagrasses showed some species in the Indian River Lagoon, although in increase during the years 199i-98'"'. Mosquito Lagoon, a sub-estuary of the Indian River

In the Indian River, dredge spoil islands Lagoon. Ruppia maritima is more common than vegetated with mangroves and Australian pines dot Synngodium filiforme. Elsewhere in the Indian River,

the intercoastal waterway; bridges and supported Ruppia maritima is common and grows in both salt

highways cross the river to provide access to the and fresh environments. The Halophila species in

coastal beaches. The east coast of Florida is subject Florida include the cosmopolitan Halophila decipiens

to hurricanes. Manatee live in the Indian River, and Halophila engelmanni, and the rare and fragile eating seagrass; many manatee are killed or Halophila johnsonii, a seagrass found only along the

scarred by boat propellers. In the cooler winter southeast coast of Florida between Sebastian Inlet

months, manatees cluster in the warm water at the |27°51'N| and Virginia Key l25''/i5'N), primarily in the

outlets of electric plants, deep boat basins and Indian River

other large facilities. Halophila johnsonii was given threatened

Seven species of seagrass are found along species status in 1998 by the National Marine

M The Caribbean 237

principal settling substrate for the recruitment of the countries. In Belize, spiny lobster and queen conch spiny lobster contribute most of the total value of exported seafood,

Seagrass beds have been recognized as estimated at US$10. A million in 1995. Spiny lobster productive fishery areas in the Caribbean""'. Soft- fishing alone is worth over US$23 million per year in bottom demersal fisheries exploit scianelds, mullets, Nicaragua. snappers, groupers, grunts, sharks, penaeld shrimp, The Caribbean is exposed to three types of loliginid squid and octopods over seagrass beds. Other natural hazard: hurricanes, volcanic eruptions and resources are free-living macroalgae Eucheuma and earthquakes. Hurricane activity may result in loss of Hydropuntla. which are collected and used to make seagrass vegetation because of sediment erosion or seamoss drinks In the Lesser Antilles and seamoss sediment deposition on the seagrass beds. In 1989 porridge in Belize. The queen conch and the spiny Hurricane Hugo, with squalls exceeding 160 knots, lobster are major fisheries resources. The queen was the most violent of the century to pass over conch Strombus gigas is associated with Thalassia Guadeloupe and Puerto Rico"". It had a more testudinum beds and Is now seriously threatened by destructive impact on Syringodium filiforme beds overfishing. The spiny lobster Panutirus argus is also a than on Thalassia testudinum. Hugo eroded very important resource fished in the seagrass beds nearshore areas, and tens of square kilometers of and on the nearby reefs. Though its abundance has highly productive seagrass meadows were destroyed decreased due to overfishing, present restrictions in by the formation of large sediment "blow-outs", holes fisheries aim to protect this resource in various in otherwise continuous seagrass meadows. Such

Fisheries Service under the Federal Endangered areas limit boats with engines in order to decrease

Species Act. It has one of the most limited propeller scarring of the grass beds. Educational

geographical distributions of any seagrass in the efforts aimed at sports fishers and boaters are

world, although it is currently under genetic study to attempting to decrease human impacts on sea-

investigate the possibility that It may be an grasses, though the impacts from land-based

introduced species'^''. Beds of Haiophila johnsonii human development are probably of greater concern are highly transient and the plants are quick growing, with individual plants reaching mature size

in about two weeks and beds often persisting no longer than a few months. Beds are often

discontinuous and patchy. Neither male flowers of Haiophiia jotinsonii nor seeds or seedlings have

been found, and it is speculated that the plants populations are maintained by vegetative growth alone'"'. The St Johns River Water Management

District has been monitoring seagrass in the Indian River since 1994. The monitoring program has

documented large changes in the distribution of some seagrasses, with Halophiita johnsonii and

other l-latophila species increasing more than 500

percent in four years at some locations. Grouper, snapper, sea trout and flounder use seagrass habitat as nursery on the Florida east coast. Bay scallops, shrimp and blue crabs also

depend on seagrasses. Controls on dredge and fill

activities set standards for turbidity, water color and

other physical parameters. There are guidelines to

protect manatee habitat and to preserve indigenous

life forms, including seagrasses, on State of Florida

submerged lands. Removal or destruction of

seagrasses in state parks is forbidden, and some Halodule wrig/if/'/ with a male flower, Florida 238 WORLD ATLAS OF SEAGRASSES

needed. Distribution data are required in order to

assess the real or potential threats to seagrass and losses. Determining the distribution of Caribbean

seagrasses is a problem because mapping of coastal marine resources using remote-sensing techniques

has only recently been refined to be able to differentiate

seagrass communities, and most countries in the Caribbean have neither the infrastructure nor the

funding to execute projects of this nature.

HISTORICAL PERSPECTIVES There are few historical reports on permanent losses of

seagrass beds in the Caribbean. Barbados and

Carriacou in the Grenadine Island chain lost

A "blow-out" in the Turks and Caicos Islands. seagrasses between 1969 and 1994. In Trinidad and

Tobago seagrass beds once found in Scotland Bay, btow-outs can migrate and expand, taking many years Grand Fond Bay (Monos Island], Five Islands, Cocorite

to recover'". (near the mouth of the Diego Martin River! and

However, in many cases, eittier tiurricanes tiad no Speyside in Tobago have disappeared.

visible effects at all" '" or recovery was relatively fast, In the past, grazing by the green turtles and

whicfi was ttie case for Thalassia testudinum in a manatees must have had an enormous impact on the

Mexican Caribbean reef lagoon in 1988 after tlie seagrass beds. The common names "turtle grass" and

passage of Hurricane Gilbert, a class 5 hurricane with "manatee grass" are a testament to the importance of

the lowest 1888 mbl ever seagrasses in the diet of the green turtle Chelonia

reported in the area"^'. In Costa Rica, the Limon mydas and the West Indian manatee Tnchechus

earthquake of 1991 resulted in a 0.5 m uplift of a lagoon manatus. The manatee and the green turtle are

and Thalassia testudinum completely overgrew it, threatened throughout the Caribbean because of

although the following year there was an equivalent overfishing and, in the case of the turtle, the collection

reduction in seagrass area'". Perez and Galindo"" of eggs for food. Although both animals have received

reported mass defoliation of Thalassia testudinum in considerable conservation status, they are still hunted. Parque Nacional Morrocoy, Venezuela, due to We can only speculate about their past impact on the hyposalinity after torrential rains, but recovery was fast seagrass communities and how these communities Iseverat months! as the apical-shoot meristems did not have changed since populations of these large die and shortly after the event formed leaves again. herbivores have diminished or disappeared. These reports indicate that overall, under natural conditions, Caribbean seagrass beds seem to be fairly PRESENT THREATS

resistant or resilient to major natural disturbances. The vast expanses of the seagrass beds in the Caribbean, together with their relatively high resistance PRESENT DISTRIBUTION or resilience to major natural disturbances, may give a The only data available on area coverage of seagrasses false sense of security and lead to the perception that

are from specific studies in which seagrasses have they are immune to human impacts. Socio- been mapped at a very local scale. The following economically. the Caribbean region includes high estimates are compiled from various sources: Mexico proportions of urban human populations and rapidly

500 km'; Belize 1 500 km^ Guatemala (one site! 20 km'; expanding agricultural and tourist-industrial frontiers. Nicaragua (Great Corn Island) 2.4 km'; Costa Rica The population growth of the Caribbean over the last 20

(Parque Nacional Cahuital 0.2 km'; Venezuela (Cariaco years has been estimated to be 58 percent"''', which has

Gulfl 500 km"'; Curacao 8 km'; Bonaire 2 km'; Tobago led to increasing pressure on the adjacent coastlines 0.64 km'; Martinique 41.4 km'; Guadeloupe 82.2 km'; and their seagrasses. Additionally, an estimated

Antigua ISeatons Harbourl 1 km'; Puerto Rico (La 12 million tourists per year visit the Caribbean region. Parguera, Guayanilla Bayl 27.68 km'; Jamaica The number of tourists who visited the Belize Barrier

(Discovery Bayl 0.5 km'; Cuba ICayo Coco, Sabana- Reef Complex in 1994 was 128000, generating an Camaguey Archipelago! 75 km'; Grand Cayman 25 km'. estimated US$75 million. More extensive mapping may have been carried On local scales, seagrasses are being destroyed out but area estimates not published; further mapping or removed by the construction of coastal develop-

and distribution studies in the Caribbean are badly ments associated with tourism or other coastal The Caribbean 239

activities. Tourist developments are accompanied by eutrophlcation Isewage and agricultural fertilizers!, the construction of harbors and docl

Parguera, Puerto Rico, increased traffic of ships and surface runoff Ifor example, rivers!, distinct point recreational vessels are causes of anchor damage, sources (effluents from sewage treatment plants) or littering, trampling, propeller scarring, fuel impacts, multiple point sources Isuch as submarine springs detrimental shading of the seagrasses by marinas and connected to the aquifers that are contaminated by piers, and damage of the beds by dredging. Seagrass land-based human activities!. The detrimental effects beds in front of hotel beaches are often removed, for of diffuse river loads are exacerbated by erosion of example in Pointe Sable National Park on St Lucia, in watersheds caused by deforestation, urbanization and

Venezuela and in Mexico. At other sites, seagrasses agricultural activities. Throughout the Caribbean, the have been removed to make way for salt production and impact of moderate eutrophlcation on seagrass mariculture; seagrass beds were used for the ecosystems results in changes in community structure cultivation of seamoss [Gracilana spp.l in St Lucia. In or species composition and higher productivity of

Guatemala 95 km' were lost between 1965 and 198A to epiphytes on seagrass leaves. As nutrient loads shrimp and salt production. In St Lucia, dynamite Increase, epiphytes or drifting algal masses become fishing has destroyed seagrass areas. Damage of more abundant, resulting in a decline in seagrass shoot seagrasses through illegal sand mining from beaches density, leaf area and biomass.

Is widespread, particularly in the smaller islands. Sand Rapidly increasing development throughout the mining suspends sediments and alters local Caribbean will result in an ever-increasing load of hydrodynamics. The seagrasses at Ambergris Cay, wastewater nutrients into coastal marine environ- Belize, have been damaged by dredging Isand ments; such loading has already been particularly extraction and deposition], and Belize has suffered damaging to seagrasses at Curacao, at Antigua and coastal erosion because of sand land seagrass! Barbuda and in Jamaica. Oil is drilled In the southern removal. region of the Caribbean with Venezuela and Trinidad Pollution from land-based sources varies from and Tobago being the principal producing countries"". country to country. The greatest threats are from In 1986, 8 million liters of crude oil spilled onto

Case Study 23.2 PARQUE NATURAL TAYRONA, BAHJA DE CHENGUE, COLOMBIA

The small bay (3.3 km^j of Bahia de Chengue is 1 831 g dry weight/m^ with green leaves representing

situated on the Caribbean coast of Colombia in the less than 10 percent of that weight. Productivity has

Parque Natural Tayrona'". The bay contains been estimated as 1.71-5.36 g dry welght/mVday sedimentary beaches, rocky shores, small lagoons Twenty-six shrimp species have been identified and small rivers. Mangroves, coral reefs and within the Thalassia testudinum beds.

seagrass beds consisting mainly of Thalassia The importance of the site lies in its proximity

testudinum occur in the bay. Four other seagrass to Santa Marta and the Instituto de Investigaciones

species [Synngodium fiUforme. Halodule wrightii, Marinas y Costeras IINVEMAR! and because it is Halophila baillonii and Halophila decipiens] are also relatively well preserved. Only one family lives on

found in the bay Synngodium filiforme can form the bay and there is no road, so tourists are rare.

monospecific patches. There is fishing and small-scale salt mining in the

Corals of the genera Manicina, Siderastrea. bay, and fishermen sometimes use dynamite to

Millepora. Diapona, Pontes and Cladocora grow fish. Gill nets and beach seines are extended across within the Thalassia testudinum beds. Sea urchins the seagrass beds.

and seaweeds, such as l-ialimeda opuntia, are Bahia de Chengue is a CARICOMP site and is common within the beds. thus regularly monitored. Such programs usually

Biological diversity is considered to be high at attract future studies to the regions where they are

Parque Natural Tayrona because of the range of initiated. This seagrass site is representative of

habitats. For example 372 fish species have been the region, although it is relatively protected reported for this area. Thalassia testudinum from human impacts and receives special attention biomass has been estimated as between 631 and from scientists. 240 WORLD ATLAS OF SEAGRASSES

Case Study 23.3 intermixed with Thalassia testudinum (between ca PUERTO MORELOS REEF NATIONAL 20 and 250 g dry weight/m'l, but can attain high PARK values [>500 g dry weight/m^l in small monospecific patches or fringes'"'. Puerto Morelos Reef National Park IParque The (vlexican Caribbean coast of the Yucatan

Nacional Arrecifes Puerto Morelosl is situated at Peninsula has undergone immense growth over the

2rOO00' and 20%8'33"N. and 86°/i6'39"Wand has last four decades. It is now one of the premier

an area of ca 90 knn^ It extends along the northern destinations for resort tourism within the Caribbean.

part ot an extensive barrier-fringing reef complex Amongst the major attractions are the crystal-clear

that runs from Belize to the Yucatan Strait Itvlexico), seas, the white-sand beaches and the reef the second largest barrier-fringing reef complex in ecosystems. The reefs of Puerto Morelos received

the world. In this park, three seagrass species and the status of National Park through presidential IbU macroalgal species have been reported, declaration in February 1998. The effects of together with 669 species of marine invertebrate and increased population pressure throughout the

vertebrate fauna"*'. The dominant ecosystems are region have been substantial. Puerto Morelos has coral reefs, seagrass beds and the inland changed from a tiny fishing village to a rapidly mangroves which are separated from the marine growing community of approximately 3000 residents environment by sand berms 2-3 m high. During and 2 500 hotel rooms'^*'. Several significant periods of exceptionally heavy rains, overflow of potential sources of nutrients occur in the region: mangrove wetlands exports brackish tannin-colored hotels, intensive farming, rubbish disposal and

waters into the lagoon. The Yucatan limestone is residences. extremely karstic. and rainwater rapidly infiltrates Although the Puerto Morelos Reef National

into the aquifer, resulting in the absence of surface Park lagoon is relatively pristine, the increasing

drainage or rivers. Rainfall varies between 1.1 and pressure of human development is starting to be

1.3 m per year, and the water passes through an noticeable. The village of Puerto Morelos is not yet immense network of underground caves and equipped with a central sewer system, and wastes

channels to vent into marine coastal areas through are discharged into septic tanks or directly, without submarine springs loyos del agua] and fissures. any treatment, into holes in the ground. These land

Thus, the lagoon environment is principally sources of nutrients can enter the water table and

governed by marine conditions. The water in the flow through to the reef lagoon kilometers away.

lagoon is oligotrophic: low mean nitrite 10.06 pM), Reefs in the coastal seas thrive under low natural nitrate 113.9 pMl and phosphate (0.^6 pM| nutrient concentrations (also the reason why the concentrations were recorded during 1982 and 1983. waters are so clear], which implies that any

Salinity varies little throughout the year, generally increase in nutrient input into these areas may

fluctuating between 35.8 and 36.2 psu. Surface cause drastic changes in the coastal ecosystems in water temperature varies seasonally, from ca 26°C the near future.

in the winter (extreme minimum of 12.5°CI to 31°C

in the summer (extreme maximum 3i.5°Cl. The

vegetation in the lagoon largely consists of Thatassia testudinum, accompanied by Synngodium filiforwe (occasionally Halodule wrightn] and rhizophytic and calcareous algae growing on coarse carbonate sand. Halodule wrightii forms very narrow fringing zones

near the beach. During 1990-91, total biomass ot

Thalassia testudinum in Puerto Morelos reef lagoon

attained annual mean values of 573 g dry weight/m' in a back-reef station, 774 g dry weight/m' in a

coastal fringe area and 81 1 g dry weight/m' in a lush

bed in a mid-lagoon station: leaf biomass

constituted between A.8 and 8.6 percent of total biomass'"'. Total biomass of Synngodium filiforme

or Halodule wrightii is usually small when growing Thalassia testudinum sfioot with a female flow/er

H-/ The Caribbean 241

seagrasses at Bahia Las Minas, Panama"". Thalassia testudinum initially suffered blade damage and browning but eventually recovered, except tor a 20-90

cm wide stioreward margin where ttie seagrass died

off. Syringodium filiforme, which proved to be more

sensitive, still had lower biomass two to three years after the event. The density of seagrass infauna was

reduced by a factor of three at oiled sites. Additionally,

effluent from bauxite mining has been reported to

damage seagrass beds in Jamaica, Surmame, Guyana, the Dominican Republic and Haiti"". Often different factors of human impact act

synergistically and together they are responsible for

severe seagrass loss. For example, overfishing of wrasses and triggerfish off the coast of Haiti and the US

Virgin Islands caused an explosion in sea urchins which

then destroyed the seagrass beds by overgrazing. In

Jamaica, urban and industrial pollution, dredging of

canals, landfilling, bauxite mining, oil spills, channelization, urban runoff, urban sewage,

construction of river bulkheads and docks, artificial

, thermal effluents and cement Sand dunes adjacent to Halodule wnghtiiand Thalassia testudinum tailings all degrade seagrass ecosystems"". Other beds. Ronda. USA. seagrass beds near industrial areas are also highly

impacted, such as those at Lake Maracaibo specific environmental legislation. Most countries are (Venezuela), the "El Mamonal" industrial complex formulating or have formulated marine management (Cartagena Bay, Colombia], the west coast of Trinidad system plans. Systems of marine protected areas vary and Havana Bay in Cuba"". The replanting of from country to country, but most include seagrasses. seagrasses has successfully mitigated a fraction of Of the 31 fully managed marine protected areas of the these impacts. Caribbean, 2A (7^ percent! include seagrasses"". As seagrasses actively form and maintain The CARICOMP network (Caribbean Coastal extensive subtidal flat structures in the Caribbean, Marine Productivity network! was set up to monitor there is concern about the effects of global warming coral reefs, mangroves and seagrasses'". In this and sea-level rise on seagrasses. Models of global network, associated marine laboratories and conser- climate change predict considerable changes for the vation units work together, using standardized tech- coastal environments of the Caribbean, including rising niques to measure the target ecosystems. CARICOMP sea level, increasing water temperature and more was established in 1985, the associated network in 1990 frequent hurricanes. Seagrasses should be able to and operation of the network was initiated at the end of maintain vertical rates of habitat accretion in pace with 1992. The stated aims of CARICOMP are "to determine predicted rises in sea level until at least the middle of the dominant influences on coastal productivity, to this century, and a rise in sea level is not expected to monitor for ecosystem change, and ultimately to seriously affect the predominant species unless a discriminate human disturbance from long-term general deterioration of the habitat occurs'"'. natural variation in coastal systems over the range of

their distribution". To these ends, CARICOMP is

POLICY, REGULATION, PROTECTION coordinated through a Data Management Centre at the

In the Caribbean, two major intergovernmental efforts University of the West Indies in Jamaica. Seagrass to protect the environment can be singled out: the parameters such as biomass, areal productivity and

Caribbean Environment Programme of the United turnover, shoot density, leaf width and length, and leaf Nations Environment Programme (CEP-UNEPI and the area indices are measured twice yearly. CARICOMP Meso American Barrier Reef Project (Sistemas involves 27 institutions in 17 countries where Arrecifales Mesoamericanos) which forms part of the seagrasses are being, or will be, monitored'". Corredor Biologico Mesoamericano (CBMl. Both include countries of the Caribbean which have ACKNOWLEDGMENTS recognized the desirability of managing marine coastal We would lil

Soto. The first author was supported by fellowships from CNPq and UERJ Xavier 524, CEP 20559-900, Rio de Janeiro RJ, Brazil. Tel: +55 10121 2587

IProciencial during the preparation of this chapter The third author is 7328. Fax: +55 10121 2587 7655. E-mail: jcreedOopenlink. com.br

grateful to Tracy Blanchon for critically reviewing the manuscript,

Ron C, Phillips, 3100 So. Kinney Road #77, Tucson , Arizona 85713, USA. AUTHORS

Joel C. Creed, Laboratorio de Ecologia Marinha Bentica. Departamento Bngitta I. Van Tussenbroek, Unidad Acdemica Puerto Morelos, Instituto

de Ecologia, Instituto de Biologia Roberto Alcantara Gomes, Universidade de Ciencias del l^lar y Limnologia, Universidad Nacional Autonoma de

do Estado do Rio de Janeiro - UERJ, PHLC Sala 220, Rua Sao Francisco (Mexico, Apdo. Postal 1 1 52, Cancun, 77500, Quintana Roo, Mexico.

REFERENCES 17 UNEP [1994]. Regional Overview of Land-based Sources of the Region. Technical 1 Phillips RC [19921. The seagrass ecosystem and resources in Latin Pollution in Wider Caribbean CEP Report

America. In: Seeliger U led! Coastal Plant Communities of Latin No. 33. America. Academic Press, San Diego, California pp 107-121. 18 Marshall MJ, Batista V, Mafias D [1993]. Effects of the 1986 Bahia

2 Littler DS, Littler MS 120001. Caribbean Reef Plants. Offshore Las Minas, Panama, oil spill on plants and animals in seagrass Graphics, Washington. communities. In: Keller BD, Jackson JBC [edsl Long-term

3 UNESCO [1983]. Coral Reefs, Seagrass Beds and Mangroves: Tfieir Assessment of the Oil Spill at Bahia Las Minas, Panama Synthesis

Interaction in tfie Coastal Zones of the Caribbean. UNESCO Reports Report. US Department of the Interior Minerals Management

in l»larine Science 23. Service OCS Study MMS 93-0048.

4 Kilar JA, Norris JN [19881. Composition, export, and import of drift 19 Thorhaug A, Miller B, Jupp B, Bookers F [19851. Effects of a variety

vegetation on a tropical, plant-dominated, frmging-reef platform of impacts on seagrass restoration in Jamaica. Marine Pollution

[Caribbean, Panama!. Coral Reels T. 93-103. 6u«e(/n 16: 355-360.

5 Freile D, Hillis L [19971. Carbonate productivity by Halimeda 20 UNEP [1993]. Ecosystem and Socioeconomic Response to Future

incrassata in a land proximal lagoon, Pici Feo, San Bias, Panama. Climatic Conditions in the Marine and Coastal Regions of the

Proceedings of 8th International Coral Reel Symposium 1:767-772. Caribbean Sea, Gulf of Mexico, Bahamas, and the Northeast Coast

6 Patriquin DG [1975], "fvligration" of blowouts in seagrass beds at of South America. CEP Technical Report No. 22.

Barbados and Carnacou, West Indies, and its ecological and 21 Kelleher G, Bleakley C, Wells S [1995] A Global Representative

geological implications. Aquatic Botany ]-. 163-189. System of Marine Protected Areas. Vol. 4. Environment

7 UNESCO (19981. CARICOMP - Caribbean Coral Reel. Seagrass and Department, The World Bank, Washington.

Mangrove Sites. Coastal Region and Small Island Papers 3. 22 Morris LJ, Virnstein RW, Miller JD, Hall LM [1999]. Monitoring

8 Williams SL [1990]. Experimental studies of Caribbean seagrass seagrass changes in Indian River Lagoon, Florida using fixed development. Ecological Monographs 60: W9-469 transects. In: Bortone SA [edi Seaprasses: Monitoring, Ecology,

9 Van Tussenbroek Bl, BrearleyA [1998]. Isopod burrowing in leaves Physiology and Management. CRC Press, Boca Raton, pp 167-176.

of turtle grass, Thalassia testudinum, in a t^exican Caribbean reef 23 Waycott, M. Personal communication.

lagoon. Marine and Freshwater Research '>'): 525-531. 24 Heidelbaugh WS, Hall LM, Kenworthy WJ, Whitfield P, Virnstein

10 Sturm MG de L [1991]. The living resources of the Caribbean Sea RW, Morris LJ, Hanisak MD [1999]. Reciprocal transplanting of the

and adjacent regions. Caribbean Marine Studies 2: 18-W. threatened seagrass Hatophila/ohnson/; [Johnson's seagrass] in

11 Rodriguez RW, Webb RMT, Bush DM [1994]. Another look at the the Indian River Lagoon, Florida. In: Bortone SA [ed] Seagrasses:

impact of Hurricane Hugo on the shelf and coastal resources of Monitoring, Ecology, Physiology, and Management. CRC Press,

Puerto Rico, USA. Journal of Coastal Research 10: 278-296. Boca Raton, pp 197-210.

12 Glynn PW, Almodovar LP, Gonzalez JG 11964). Effects of hurricane 25 INE [Instituto Nacional de Ecologia, Comunidad de Puerto Morelos,

Edith on marine life in La Parguera, Puerto Rico Caribbean Quintana Pool [2000]. Programa de manejo del Parque Nacional

Journal of Science 4: 335-345. Arrecife de Puerto Morelos. Instituto Nacional de Ecologia, Mexico,

13 Van Tussenbroek Bl [1994]. The impact of Hurricane Gilbert on the DR 222 pp.

vegetative development of Thalassia testudinum in Puerto Morelos 26 Van Tussenbroek Bl [19981. Above- and below-ground biomass and

reef lagoon, Mexico- A retrospective study. Botanica Marina 37: production of Thalassia testudinum in a tropical reef lagoon 421-428, Aguatic Botany i>\:b'l-S2.

14 Perez D, Galindo L [2000], Effects of hyposalmity in Thalassia 27 Gallegos ME, Merino M, Rodriguez A, Marba N, Duarte CM [1994]. testudinum [Hydrocharitaceael from Parque Nacional Morrocoy, Growth patterns and demography of pioneer Caribbean seagrasses Venezuela, Revista Biologia TropicaUS. [Supplement] 243-249, Halodule wrightii ani Syringodium fililorme. Marine Ecology

15 UNEP[1997]. Glol)a/enwro(imen(Ou(/oo/(. Oxford University Progress Ser/es 109: 99-104. Press, New York.

16 Vera B [1992]. Seagrasses of the Venezuelan coast: Distribution and

community components. In: Seeliger U led] Coastal Plant

Communities of Latin America. Academic Press, San Diego,

California, pp 135-140.

ll

tt South America: Brazil, Argentina and Chile 243

Ik The seagrasses of SOUTH AMERICA: BRAZIL, ARGENTINA AND CHILE

J.C. Creed

The geographical region considered includes the also expect to find, are restricted to the Caribbean and coastlines and islands of the following countries: are not found in the southwest Atlantic. Consequently,

Brazil, Uruguay, Argentina, Chile, Peru and in the northeast of Brazil Halodule wrightii is able to

Ecuador These coastlines stretch from about 5°N to form large monospecific beds, such as those found at

57°S and from 82°W to 3/.°W; thus they are influenced Itamaraca Island. by both the Pacific and Atlantic Oceans. In Brazil, Halodule wrightii is the seagrass that

Phillips'" stated in 1992 in a review of seagrass most frequently occurs and has the widest distribution. ecosystems and resources of Latin America that "the Halophila baillonii, which is also found widely in the most basic research is needed in almost every place". Caribbean, has been reported twice lin 1888 and in the

During the subsequent decade, the number of 1980s, though not sincel at Itamaraca Island, in the published reports of surveys, biology and ecology of the northeast of Brazil. Large extents of the Brazilian seagrasses of South America has increased somewhat. coastline have no recorded seagrasses, either because However, despite the fact that some progress has been seagrasses have not yet been found or because they are made with respect to Phillips's comment, it must be not present. The continental shelf is sometimes as recognized that much important information remains narrow as 15 km, and for this and other reasons unavailable as gray literature or, as is often the case, no extensive reefs have not developed in Brazil. information has been collected. Consequently, along most of the coast Halodule

wrightii is restricted to estuaries, bays and other ECOSYSTEM DESCRIPTION protected ecosystems. Although South seagrasses are the subject Where the continental platform widens, such as of some taxonomic debate, at least six seagrass in the Abrolhos region of Brazil, the formation of species have been reported for the region; nearly all extensive reefs allows the establishment of are restricted to the Atlantic coast. In the southwest seagrasses, which thrive in these protected areas. Atlantic, seagrasses are common but rarely form very Here, beds of Halodule wrightii [2-7 m) and Halophila extensive meadows. Remarkably, the only seagrasses decipiens 15-22 ml become more common. Halophila known on the Pacific coast of South America are decipiens reaches its southernmost limit in the a couple of small populations of Heterozostera Atlantic Ocean in Guanabara Bay at Rio de Janeiro, tasmanica (now Zostera tasmanica] in northern Chile at right under the famous Sugarloaf Mountain. Because

Coquimbo'^'. Intriguingly, this species is otherwise it can occupy deeper waters, Halophila decipiens may known only from Australia; it has been suggested that be of greater ecological importance than has these are remnants of formerly widely distributed previously been thought, but its distribution is still Chilean populations'". No seagrasses are known for not very well known. As these species reach the Peru or Ecuador southeast of Brazil they form smaller and more Shoalgrass [Halodule wrightii] and sea vines isolated populations.

[Hatophita decipiens] have a tropical-subtropical Halodule emarginata is a species endemic to distribution in the southwest Atlantic, stretching from Brazil, and forms small populations from northeast to the Caribbean to the Brazilian states of Parana and Rio southeast Brazil. However, there is no agreement as to de Janeiro, respectively. Surprisingly, Syringodium whether Halodule emarginata should be maintained filiforme and Thatassia testudinum, which one might as a distinct species from Halodule wrightii. Leaf-tip n\ ft 24A WORLD ATLAS OF SEAGRASSES

characteristics are used to distinguish! ttie species, Heterozostera tasmanica but that it was unlikely that it

which rarety flower or fruit. came from so far away as Chile.

Ruppia maritima is found sporadically from The dearth of studies dealing with seagrasses in

Brazil down to Argentina, where it forms the South America can be exemplified by the Brazilian southernmost populations of seagrass in the world, at experience, although Brazil has the most studies the Magellan Straits'^'. Such records reflect the available. After a pioneering study of the biota species' wide latitudinal distribution and tolerance to associated with Halodute wrightii by Kempf"', few

variable environmental conditions, as it can be found studies were carried out until the 1980s. From 1980

growing in coastal lagoons and estuaries with until the present, an average of 22 additional

salinities from to 39 psu. At the Patos Estuarine companion species a year have been reported

Lagoon in southern Brazil, a large labout 120 km') area associated with the Brazilian seagrasses and the trend

of Ruppia maritima dominates the benthos and local suggests that this rate will continue"^', demonstrating primary productivity. that seagrass habitats are attracting research effort An unattached leaf of what was reported as (Figure 2^,1|. However only one or two research Zostera has been found at Montevideo, Uruguay. papers relating to seagrasses of the region are

Phillips'" commented that the leaf tip resembled that of published each year.

Case Study 24.1 ITAMARACA ISLAND, NORTHEAST BRAZIL

The regional importance of the populations of The area of Itamaraca is one of the most

seagrasses at Itamaraca Island, Pernambuco State productive fisheries in the state of Pernambuco. and (7°45S. 3i°50'WI has been recognized for some the seagrasses contribute as a nursery and foraging

"'. regression in time" ' At Itamaraca there are large expanses of area. Local inhabitants have reported

Hatodule wrightii on the eastern side of the island in the areal coverage of Halodute at Itamaraca.

shallow-water flats protected from the open sea by Furthermore, the local fishermen report that a

reefs. Locally, Halodute is known as capim aguthia reduction in the area of Halodute has resulted in a

which means needlegrass. In 1967, Hatodute drop in fisheries production, especially of prawn and

stretched approximately 1 .2 km seaward in a mapped halfbeaks. It has been suggested that coastal practices, landfill, portion 1 .2 km wide (1 .4 km'l, although the total area development, bad landuse

IS greater but unknown'". Hatoptiila bailtonii, only pollution and an increase in tourism are responsible.

found at Itamaraca in Brazil, is known from Local researchers have recommended that environ-

collections in the Santa Cruz Channel made in 1888 mental education programs be implemented to help

and in the 1980s, and has not been found since'". preserve and manage the ecosystem. Three basic research needs have been

ECOLOGICAL INTERACTIONS highlighted at Itamaraca Island: There are ecological interactions between the the realization of a survey of the distribution of seagrasses and the local mangrove, estuarine and the seagrass meadows and their associated

reef systems. The fauna is taxonomically diverse: flora and fauna; over 100 macrofaunal and 46 epiphyte floral taxa the identification of impacting anthropogenic

have been identified in or on l-lalodute at agents; Itamaraca'". Amongst the l-latodule beds at the development of research programs which Itamaraca are clams, shrimp, lobsters, stone and identify the regional ecological importance of

blue crabs, and common and ballyhoo halfbeaks, all seagrasses'".

of which are fished recreationally and commercially. The region's seagrass beds are feeding grounds for The Itamaraca area stands out because: the West Indian manatee. About 12 metric tons a there is a co-occurrence of seagrass species;

year of Halodute wrightii are collected for fodder for Halodute wrigtitii. a known pioneer in the

captive-reared manatees at the Centre de Pesquisas Caribbean seagrass succession, here is the do Peixe-boi Marinho (National Manatee Research climax dominant; Centre! run by the Instituto Brasileiro do Meio- the seagrass beds are of commercial Ambiente e Recursos Naturais Renovaveis IBAMA. importance and may be suffering die-back due

which is located on the island. to human activities. ,

South America: Brazil, Argentina and Chile 245

•W-w 500

• rX ruX Jxmando dc Noronha m ECUADOR' I •• 'o •• • llamaiaca Island- H 300

• '^ 200 Abrolhos Bank and ^,.^ j Marine National Parfc^

Cumulativ

• Rio de Janeiro C3 ^ sao Paulo • 4 iiuiinuhiiru Buv • • ^

1960 1970 1980 1990 2000 URUGUAY Year reported

Figure 2i.1

Cumulative number of companion species to the Brazilian seagrasses reported since I960""' P- A TLANTIC OCEAN

Kir- BIOGEOGRAPHY Magellan Straits South American seagrasses are often found near to, or 400 800 1200 1600 2000 KilomelefS closely tropfiically linked with, other marine and coastal ecosystems and habitats, and this juxtaposition Map 2i.1 results in heightened diversity. For example, recent South America studies which have compared the macrofauna associated with Halodule wrightii and Halophila seagrasses from the Caribbean to Brazil are the green decipiens beds with nearby areas devoid of vegetation turtle Chelonia mydas^'"' and the West Indian manatee have shown that total density, richness and the Trichechus manatus'". Both have benefited from diversity of the infauna is enhanced by the presence of specific conservation action sponsored privately and by seagrasses. Coral reefs extend from the Caribbean to the Brazilian environmental agency IBAMA (green Abrolhos, Brazil, and mangroves to Santa Catarina turtles by the Projeto TAMAR and manatees by the

State, Brazil, where they are replaced by salt marshes Projeto Peixe-Boi Marinho). The black-necked swan and mud flats. Cygnus melancoryphus and the red-gartered coot

Halodule is associated with shallow habitats Fucila armillata also feed directly on Ruppia maritima without much freshwater input, such as reefs, algal in southern Brazil and Argentina but are not beds, coastal lagoons, rocky shores, sand beaches and endangered'". Recently, the semi-aquatic capybara unvegetated soft-bottom areas and nearby mangroves Hydrochaeris hydrochaeris, which is the world's without too much salinity fluctuation. Halophila is largest rodent, was observed feeding on Ruppia associated with deeper reefs, algal and marl beds, and maritima near Rio de Janeiro. Amongst the fauna deeper soft-bottom vegetated areas. Ruppia maritima which use seagrasses as a habitat are two corals, can be found in low-salinity (coastal lagoon, estuary, Meandrina brasiliensis and Siderastrea stellata. They fishpond, mangrove, salt marsh and soft-bottom grow unattached in Halodule wrightii beds and are sold unvegetated! and high-salinity (coastal lagoon, salt as souvenirs locally. pond, soft-bottom unvegetated] habitats. While the seagrasses of South America

Seagrass beds in South America are known to be contribute to coastal protection and local productivity, important habitat for a wide variety of plants and and thus fisheries, there is hardly any information animals. About 5^0 taxa (to genus or species level) of available about the value of seagrasses to the local organisms associated with the Brazilian seagrasses economy. Economically important fish species such as have been compiled by Creed'*'. The groups that the bluewing searobin [Prionotus punctatus], contributed most to species diversity are polychaetes, whitemouth croaker [Micropogonias furnieri] and fish, amphipods. decapods, foraminifera, gastropod mullet (Mug/7 platanus] are found and fished in and bivalve mollusks, macroalgae and diatoms. Brazilian seagrass beds. Local fisheries exploit Two threatened species which feed directly on commercially important crustaceans such as blue 246 WORLD ATLAS OF SEAGRASSES

ebraea], rockshells [Thais haemastoma], oysters [Ostrea puelchana] and cockles [Trachycardium

muricatum]'^'. In Chile, the Chilean scallop [Argopecten

purpuratus] preferentially settles in Zostera tasmanica beds'".

HISTORICAL PERSPECTIVES As no detailed seagrass mapping work has been

carried out in South America, there is little anecdotal or

factual information about changes in seagrass dis-

tribution and abundance. It is thought that the Zostera

tasmanica beds in Chile are historically remnant populations of much larger meadows'". Researchers

from the Universidade Federal Rural of Pernambuco

are currently mapping Halodule wrightii beds at Itamaraca Island, Brazil. This should allow some

measure of loss over the last ^0 years to be estimated, V"* • « • as the area was partially mapped before, in the 1960s.

For now, the only quantified seagrass loss is of

Halodule wrightii beds at Rio de Janeiro. These were

listed by Oliveira e( a(."' and were revisited ten years

later'"". Seagrass was no longer found at 16 percent of these sites. Losses are not due to direct use of seagrasses, as the only known use of Halodule wrightii

Siderastrea stellata, a coral that occurs m a wide range of shallow is to feed captive-reared manatees.

habitats and is common in seagrass beds. PRESENT DISTRIBUTION

Estimating the real area of seagrass cover in South

America is at present almost impossible because of

the dearth of studies. The little data available allow only an educated "best guess". Brazil probably has about 200 km' of seagrasses, Chile 2 km^ and

t Argentina about 1 km^

1 PRESENT THREATS

As Phillips'" pointed out, all seagrasses found from

\ Mexico to southern Brazil are species characteristic of the western tropical Atlantic Ocean, so management

problems concerning them relatively similar. I ~4^^l should be In fact, some general observations of threats to marine ! ^^^^^^ coastal ecosystems are pertinent. The population of ^ Latin America continues to grow, from 179 million to ^il^^^H 481 million between 1950 and 1995"". The concen- tration of population growth in urban areas and

marginal agricultural lands is the main factor respons- * __*3^H ible for pressures exerted by human population on the

/. .: /-, h : ,; ;poradically from Brazil down to Argentina environment"''. In South America, this pressure is

concentrated in the coastal cities. The continent has crabs [Caltinectes sapidus], stone crab {Menippe several large urban centers: Sao Paulo, Brazil,

nodifronsl, lobster [Panuiirus argus and Panulirus population in 2000 27.9 million (second largest city in

iaevicauda] and shrimp [Penaeus brasiUensis and the world I; Buenos Aires, Argentina, 1 l.i million (12th|;

Penaeus paulensis], all associated with seagrass beds. Rio de Janeiro, Brazil, 10.2 million I16thl"-". By 2020,

Other shellfish which are commercially collected from over 80 percent of the population of South America is

seagrass beds are clams [Anomatocardia brasiUana. expected to live in urban areas"". Such concentrations Tagelus piebeius, Tivela mactroides], volutes [Votuta put incredible stresses on the coastal marine South America: Brazil, Argentina and Chile 247

environment. Human activity affects the environment in metalworking activities, by polychlorinated biphenyl tfiree major ways: landuse and [andcover change, the congeners and organochlorine compounds, and by extraction and depletion of natural resources, and the nutrients from agricultural runoff and sewage production of wastes. discharge have all been reported. Effects of physical

It is necessary at least to l

Case Study 24.2 ABROLHOS BANK, BAHIA STATE, NORTHEAST BRAZIL

The Abrolhos Bank is formed by a widening of the surgeonfish (seagrass stomach contents: Kyphosus

continental shelf at the extreme south of the state of spp. 12 percent: Acanthurus chirurgus 8 percent;

Bahia |18°S, 38°Wl. The area consists of an inner Sparisoma and Scarus 0.5-5 percent""! and green

line of reef banks, a small archipelago of five islands turtles [Chelonia mydas which has been observed with embryonic fringing reefs, and outer reef taking 32 bites of Haloduie wnghtii per minute in

banks"". The Abrolhos Marine National Park situ] heavily graze the seagrass and 56 associated protects the archipelago, surrounding waters and an seaweed species. Predatory fish of commercial

inshore reef system. Peculiar to the area are reef importance hunt over the seagrass beds and juvenile

columns called chapeiroes which typically extend yellowtailed snapper and angelfish live in the from a depth of about 20 m to the surface seagrass. The Abrolhos Archipelago receives about

Nearshore areas are subjected to higher turbidity 900 tourist boat visits per year and is an important

because of local river inputs but offshore areas are ecotourist destination"^'. Despite being protected characterized by less turbid waters. within the national park, the seagrass beds have lost

Despite the considerable research interest 0.5 percent per year because of anchor damage,

invested in the national park, until recently"^' showing reduced seagrass density and a change in

seagrasses were overlooked and not reported. In the community structure which can take more than

fact, Haloduie wnghtii and especially Halophila a year to recover after a single impact"*'. Buoys were decipiens are more common than previously installed recently which should alleviate the

believed. Haloduie wrightii is found in shallow sandy problem, but despite its desirability no trans-

areas interspersed with coastal reefs and around the plantation has been carried out to mitigate the

Abrolhos Archipelago, while Halophila decipiens is losses suffered so far

found down to at least 22 m. The suspicion that Halophila decipiens may be very abundant on the

Abrolhos Bank was confirmed in a recent rapid

assessment protocol of biodiversity carried out in

the region"". Of the i5 reef edge/soft-bottom sites

selected, Halophila was present at 18 [AO percent!.

Although no total area quantification was made, these sites were distributed over a study area of

about 6000 km', so the potential importance of

Halophila decipiens in the region, especially in

terms of primary productivity, could be enormous.

Very little is known about the biology or ecology of

Halophila decipiens in Brazil. The Abrolhos Bank has important reef-based

and open-sea fisheries. In Abrolhos, there are trophic interactions between seagrass beds and reefs across distinct grazing halos. Large vertebrates, such as sea chub, parrotlish and Redonda Island, Abrolhos Archipelago, Brazil.

fi 248 WORLD ATLAS OF SEAGRASSES

maritima has suffered from reduced fresfiwater inputs criteria, 100 percent of Chilean and Argentine, and "highly because of nee irrigation, population growth and lock AO percent of Brazilian seagrasses are construction. threatened". Thirty-six percent of Brazil's seagrasses Acknowledging that there are intrinsic human- are "moderately threatened" and 24 percent are in "low related pressures on the coastal zone, and that these threat" areas. have been quantified for the South American continent, the superimposition of known threat potential onto the POLICY, REGULATION, PROTECTION known seagrass distribution can provide a measure of Seagrasses are not specifically protected by legislation the threat to South American seagrasses. Using these in Brazil, Chile or Argentina but are covered by resource

Case Study 24.3 RUPPIA MARITIMA IN THE PATOS LAGOON SYSTEM

The Ruppia maritima meadows in the Patos Lagoon, beds. Eleven percent of the water area has been lost substantial near the city of Rio Grande, Rio Grande do Sul |32°S, since the 1700s and this includes areas 52°Wl have received more research attention than of Ruppia meadow; many anthropogenically filled seagrasses. any other seagrass system in South America, The areas were previously inhabited by Patos Lagoon consists of shallow bays with mean Areas of preservation, conservation and develop- annual water depths of 20-70 cm. The Ruppia ment have been proposed for the region, Ruppia maritima meadows occupy an area of about 120 km' beds would be partially protected under such a

of the estuary system. Considerable scientific proposal. However, "management efforts of the knowledge has been accumulated about these Patos Lagoon estuary are hampered by technical seagrass beds during the last 25 years, and has and legal problems"'". The Ruppia beds continue to recently been summarized""'. Ruppia forms be studied as part of the Brazilian Long Term Locally extensive beds in these shallow marginal bays with Ecological Research Program IPELDI. both annual and perennial populations, depending Ruppia maritima is called lixo-capim which means on local environmental factors, interspecific (algall weedgrass. shading and epiphyte fouling"". When compared with other seagrass habitats worldwide, light

attenuation in the waters of the Patos Lagoon is

relatively high, and consequently Ruppia is restricted

to relatively shallow water'". This imposes seasonal influences on primary productivity; net annual primary productivity of Ruppia maritima has been estimated as 39.6-43.2 g carbon/mVyear'", The Ruppia meadows interface with sandy shorelines, unvegetated tidal flats and salt marsh

habitats. The large areas of Ruppia meadows serve as complex habitats for a local fishery by providing substrate, refuge, nursery and feeding grounds.

Associated drift algae can also be locally abundant alternative habitats. Pink shrimp lea 2800 metric

tons landed annually in the region! and the blue crab

lea HOD tons), found foraging in the seagrass, are important local artisanal fishery resources.

Whitemouth croaker lea 7500 tons! and mullet lea 2300 tons! also use the Ruppia beds as nursery or foraging grounds. The stout razorclam |7age/us

ptebius] IS another commercially important species. Predators such as the bottlenose dolphin are common 131-100 individuals within the lagoon

system) in the Patos Lagoon and feed principally on

whitemouthed croaker which is found in the Ruppia South America: Brazil, Argentina and Chile 249

management and conservation legislation. Brazil has comprehensive environmental legislation. The Federal

Constitution of 1988 dedicates a chapter exclusively to the environment. The federal government has amongst

other items the responsibility to "preserve and restore essential ecological processes and promote the

ecological management of species and ecosystems ...

preserve the diversity and integrity of genetic resources

... protect the flora and fauna". The coastal zone is recognized as a national resource by this constitution.

In 1998, Congress approved the Environmental Crimes

Law. It regulates crimes against the natural environ- ment. Although algal beds, coral reefs and moUusk

beds are specifically mentioned, seagrasses are not. Brazil has a complex management system based

on the creation of conservation units at federal, state

and municipal government levels. Approximately 290

conservation units are recognized in the coastal zone, which represent about 21 million hectares that have

specific legislation. Of these, seagrasses are found in both (Marine National Parks lAbrolhos and Fernando de Noronhal as well as numerous ecological stations, state parks, biological reserves and environmental protected areas.

ACKNOWLEDGMENTS

I would like to acknowledge the help and information provided by the

following colleagues: Alejandro Bortolus (from Argentina], Carlos

Eduardo Leite Ferreira, Eduardo Texeira da Silva, Erminda da Conceicao

Guerreiro Couto, Kanne Magalhaes, Marcia Abreu de Oliveira Figueiredo

and Ulrich Seeliger Ifrom Brazil], and Evamana W, Koch and Ronald i Phillips Ifrom the USA). The author was supported by fellowships from

CNPq and UERJ [Prociencia] dunng the preparation of this chapter

AUTHOR The Brazilian 2 real banknote

Joel C. Creed, Laboratdno de Ecologia Marinha Bentica, Departamento depicts a turtle, corals, algae

de Ecologia, Institute de Bioiogia Roberto Alcantara Gomes, Universidade and seagrass. A closer look

do Estado do Rio de Janeiro - UERJ, PHLC Sala 220, Rua Sao Francisco linsetl, however, reveals the

Xavier 524, CEP 20559-900, Rio de Janeiro RJ, Brazil. artist's mistake - the seagrass

Tel: +55 (0]21 2587 7328. Fax: *5i IDI21 2587 7655. E-mail; IS probably Thalassia. a genus

Jcreed0openlink.com.br that IS not found in Brazil

REFERENCES Creed JC [2000]. The biodiversity of Brazil's seagrass and

1 Phillips RC 119921. The seagrass ecosystem and resources in Latin seagrass habitats: A first analysis. Biologia Marina t^editerranea

America. In: Seeliger U ledl Coastal Plant Communities of Latin 7:207-210.

America. Academic Press, San Diego, California, pp 107-121. Barros HM, Eskinazi-Leca E, Macedo SJ, Lima T ledsl [20001. 2 Gonzalez SA, Edding ME [1990]. Extension of the range of Gerenciamento participativo de estuanos e manguezais.

Heterozostera tasmanica (Martens ex AschersI den Hartog in Chile. Universitana da UFPE, Recife.

Aijuadc Botany 38: 391-395. Seeliger U, Odebrecht C, Castello JP [eds] [19971. Subtropical

3 Short FT, Coles RG (eds] [20011. Global Seagrass Research Convergence Environments: Tfie Coast and Sea of (he Methods. Elsevier Science, Amsterdam. Scuthvtestern Atlantic. Spnnger-Verlag, Berlin. i Kempf M [1967/91. Nota preliminar sobre os fundos costeiros da Aguilar M, Stotz WB [2000], Settlement of juvenile scallops

regiao de Itamaraca (Norte do Estado de Pernambuco, Brasil]. Argopecten purpuratus (Lamarck, 1819] in the subtidal zone at

Trabalhos do Instituto do Oceanografico da Universidade do Recife Puerto Aldea, Tongoy Bay, Chile. Journal ofShellfisti Research 19: 9/11:95-110. 749-755. n 69

250 WORLD ATLAS OF SEAGRASSES

Oliveira EC de, Pirani JR, Giulietti AM 11983]. The Brazilian 1 Figueiredo MAO [in press]. Diversity of macrophytes in the Abrolhos

seagrasses. Aquatic Botany lb: Ibl-lbl. Bank, Brazil. Conservation International, Washington, DC.

Creed JC. Personal observations. 17 Ferreira CEL. Unpublished data.

UNEP [1997]. Global Environment Outlook. Oxford University Press, 18 Seeliger U [2001]. The Patos Lagoon Estuary, Brazil. In: Seeliger U, New York. Kjerfve B ledsl Coastal Marine Ecosystems of Latin America.

12 UNEP [1 99i]. Regional Overview of Land-based Sources of Springer-Verlag, Berlin, pp 167-184.

Pollution in the Wider Caribbean Region. CEP Technical Report 1 Costa CSB, Seeliger U [1 989]. Vertical distribution and resource

No. 33. allocation of Ruppia maritima L in a southern Brazilian estuary.

13 den Hartog C [19721. The seagrasses of Btbzil. Acta Botanica Aquatic Botany 22: 123-129.

Neeriand/ca 21: 512-516. 20 Creed JC. Unpublished data.

14 Leao ZMAN, Kikuchi RKP [2001). The Abrolhos reefs of Brazil. In:

Seeliger U, Kjerfve B ledsl Coastal Marine Ecosystems of Latin America. Spnnger-Verlag, Berlin, pp 83-96. 15 Creed JC, Amado Filho Gl^ [1999). Disturbance and recovery

of the macroflora of a seagrass [Halodule wnghtii AschersonI meadow m the Abrolhos Marine National Park,

Brazil: An experimental evaluation of anchor damage. Journal of Experimental Marine Biology and Ecology 235; 285-306.

ri tf '

Appendix 1 251

Appendix 1: Seagrass species, by country or territory

ft) i/i ™ ^ T3 O .5 ui .y TO 1 ™ S; .- TO c -Q P q; TO -- 0) ui ra oiDQ TO ^ — TO = 5 C XI o 3 i TO N t 2 -g5 E S .^ S c S, *-; 2 E . _ CTI01'*--o l/l ^ El^ S o TO en (U-C.C — 1-— 1- 03.ti a 3—- t I_ ,.^,„ £ E Q. C b Q. N TO -, (jnj(UQ)i_i_ut-3fDfT)nj— SPECIES 'j:.coooi-3 >,

Halophila baillonii

Halophila beccarii Halophila capricorni • Halophila decipiens • / • • / / Halophila engelmanni • Halophila hawaiiana Halophila johnsonii Halophila minor / Halophila ovaiis / / / Halophila ovata • / Halophila spinulosa • / Halophila stipulacea • Halophila tricostala Phyllospadix iwatensis Phyllospadix japonicus Phyllospadix scoulen / Phyllospadix serrulatus / Phyllospadix torreyi • Posidonia angustifolia Posidonia australis • Posidonia conacea • Posidonia denhartogii • Posidonia kirkmanii / Posidonia oceanica / • Posidonia ostenfeldii / Posidonia robertsoniae Posidonia sinuosa / Syringodium filiforme • / • / • / / • Syringodium isoetifolium / / / Thalassia hemprichii Thalassia testudinum • / / / • • / • / Thalassodendron ciliatum • Thalassodendron pachyrhizum • Zostera asiatica Zostera caespitosa Zostera capensis Zostera capricorni Zostera caulescens Zostera japonica / Zostera manna Zostera mucronata' Zostera muellen'

Zostera noltii • Zostera novazelandica* Zostera tasmanica TOTAL 3 2 2 3 29 1 3 3 1 5 /I 3 4 2 4 3 2 5 2 1 12 5 6 4 3 5 3 2 5

Notes: / indicates presence of a species; indicates a species name no longer used.

Posidonia robertsoniae is conspecific witti ' Posidonia coriacea. Species that are now considered to be conspecific witli Zostera capricorni. Not including Ruppia spp. Heterozostera tasmanica is now designated Zostera tasmanica. •

252 WORLD ATLAS OF SEAGRASSES

3

(/I T3 tn fD . C m C -0 " 1- T3 T3 0) flj E nj 0) u E c c _>. ?*5 L. C ra til — 01 (U T3 -0 3 'ra L. ™ 01 i_ in : o Q. CD SPECIES LU LU LU I X X Amphibolis antarctica

Cymodocea angustata Cymodocea nodosa / / / / • Cymodocea rotundata / / • • / Cymodocea serrulata / / • / / Enhalus acoroides / • / / Habdule beaudettei Halodule bermudensis Habdule emarginata

Halodule pinilolia / / / / Halodule uninervis / • • /

Halodule wriqhtii / / • / / / Halophila australis

Halophila baillonil Halophila beccarii • Halophila capncorni / Halophila decipiens / / / / • / / Halophila engelmanni Halophila hawaiiana Halophila johnsonii Halophila minor / / / Halophila ovalis / / / / / / • / Halophila ovata / / / Halophila spinulosa / Halophila stipulacea / / • / •

Halophila tricostata Phyllospadix iwatensis / Phyllospadix japonicus / Phyllospadix scouleri Phyllospadix serrulatus

Phyllospadix torreyi

Posidonia angustilotia Posidonia australis Posidonia conacea Posidonia denhartogii Posidonia kirkmanii Posidonia oceanica / •

Posidonia ostenleldii

' Posidonia robertsoniae Posidonia sinuosa

Syringodium filiforme / / / Syringodium isoetifoUum / / / / / / Thalassia hempnchii • / / • / / Thalassia testudinum / • /•• / / / Thalassodendron ciliatum • / / / Thalassodendron pachyrhizum

Zostera asiatica Zostera caespitosa Zostera capensis Zostera capncorni Zostera caulescens / Zostera japonica / Zostera marina / / / // / / / • Zostera mucronata' Zostera muellen'

Zostera noltii // / / Zostera novazelandica' Zostera tasmanica

16 4 1 TOTAL 12 3 1 6 1 4 1 1 11 2 2 5 1 2 5 2 1 3 2 1 U 12 1 6 5 4

Notes: / indicates presence ot a species; indicates a species name no longer used.

' ' Posidonia robertsoniae is conspecific with Posidonia conacea. Species that are now considered to be conspecific with Zostera capncorni.

Not including Ruppia spp. Heterozostera tasmanica is now designated Zostera tasmanica. '

Appendix 1 253

01 ui in ^ °- ^ s ™ (D (U m (D O- 0) ll >• /T, U o- c c ra D R c - ^_ J2 o < rshall dagas laysla rtlnlqi uritan uritiu! yotte Tones 'ibati wait ID C huani; Idlves ands xIco c rea, rea, >5 tt> ~ O O D *-ran3n)fD_,(i3n5njra(u.iioo>,a;aicrcu'-'oF"Sm SPECIES ^ i£ :i ^ ^ Amphibolis antarctica

Amphibotis qriffithii Cymodocea angustata Cymodocea nodosa • / • / Cymodocea rotundata / / / • / / / / Cymodocea serrulata • // / / / / Enhaius acoroides / • • • • • • Halodule beaudettei / Hatodule bermudensis Halodule emarginata Halodule pinifolia • / / Hatodule uninenis • / /• / / / / / / Halodule wriqhtii • / • / / / / / Halophita australis Halophila baillonii / • Halophila beccarii / • Halophila capricorni Halophila decipiens • / / / / / Halophila engelmanni • Halophila hawaiiana Halophila johnsonii Halophila minor / • / / • Halophila ovalis • • // / / / / / / Halophila ovata Halophila spinulosa • Halophila stipulacea • • • / • Halophila tncostata Phyllospadix iwatensis • • Phyllospadix japonicus / Phyllospadix scoulen • Phyllospadix serrulatus Phyllospadix torreyi / Posidonia angustifolia

Posidonia australis Posidonia coriacea Posidonia denhartogii Posidonia kirkmanii Posidonia oceanica / / Posidonia ostenletdii Posidonia robertsoniae Posidonia sinuosa Syringodium filiforme • / / • • Syringodium isoetifotium / / • • / • / •• Thalassia hemprichii / / • / • / / / • • Thalassia testudinum / / • • • Thatassodendron citialum • • / / / • / • / Thalassodendron pachyrhizum Zostera asiatica • • Zostera caespitosa / / Zostera capensis • / / Zostera capricorni / Zostera caulescens / Zostera japonica // Zostera marina // / / / • • / / 1 Zostera mucronata' '

Zostera noltii • • / • 1 Zostera novazelandica' Zostera tasmanica

TOTAL 12 1 5 7 2 2 3 12 12 3 2 2 3 7 i 8 10 412 5 2 5 1 3 2 4 10 5

Notes: / Indicates presence of a species; indicates a species name no longer used.

' Posidonia robertsoniae is conspecific with Posidonia coriacea. Species tiiat are now considered to be conspecific with Zostera capricorni.

Not including Ruppia spp. Heterozostera tasmanica is now designated Zostera tasmanica. '

254 WORLD ATLAS OF SEAGRASSES

in £ in o OJ c 0) ™ iro . C (xj OJ - ro O fD c c .^ 1/1 3 c T3 > *i- (U ? SPECIES l/l l/l ^ 01 I/) i/i Amphibolis antarctica

Ampbibolis gnffithti Cymodocea angustata Cymodocea nodosa / / Cymodocea rotundata • / / Cymodocea serrulata / / / / / Enhaius acoroides • • Halodule beaudettei Halodule bermudensis Halodule emarginata Halodule pinifolia / / / Halodule uninervis / / / / / / / Halodule wrightii

Halophila australis

Halophila baillonii Halophila beccarii • • Halophila capncomi Halophila decipiens • • / / / • / • / Halophila engelmanni • Halophila hawaiiana

Halophila johnsonii Halophila minor / / / • Halophila ovalis / / / / / / Halophila ovata / / / Halophila spinulosa / Halophila stipulacea

Halophila tricostata Phytlospadix iwatensis Phyllospadix japonicus Phytlospadix scouleri Phyllospadix serrulatus

Phytlospadix torreyi

Posidonia angustifotia

Posidonia australis Posidonia coriacea Posidonia denhartogii Posidonia Ivrkmanii Posidonia oceanica

Posidonia ostenleldii

' Posidonia robertsoniae Posidonia sinuosa Syringodium filiforme / / Syringodium isoetilolium / / • / / / • • • Thatassia hemprichii • / • / / / / / Thatassia testudmum / / Thatassodendron ciliatum / / • • / / / • Thatassodendron pachyrhizum

Zostera asiatica Zostera caespitosa Zostera capensis Zostera capricorni Zostera cautescens / Zostera japonica / Zostera marina / / / Zostera mucronata' Zostera muelleri'

Zostera noltii / / Zostera novazelandica' Zostera tasmanica

TOTAL 12U 1 3 6 3 2 6 3 1 10 1 9 1 11 3 5 3 5 7 2 1 17 2

Notes: / indicates presence of a species; indicates a species name no longer used.

' Posidonia robertsoniae is conspecific with Posidonia coriacea. ' Species that are now considered to be conspecific with Zostera capricorni.

Not including Ruppia spp. Heterozostera tasmanica is now designated Zostera tasmanica. Appendix 1 255

^ -a JS ro = in -t; Lj c l/l c c _ < Qi b c < _ -) ro i- c ^ ra o ro >, (- U) c -a c N o cu > 3

Cymodocea angustata Cymodocea nodosa / / / Cymodocea rotundata • / / / / / Cymodocea serrulata / / / / / • / / Enhalus acoroides / / • • / / / Habdule beaudettei Halodule bermudensis Hatodule emarginata

Halodule pinilolia / / / / / Halodule uninervis / / / / / / / • Halodule wnqhtii / • / / Halophila australis Halophila baiUonii

Halophila beccarii Halophila capncorni Halophila decipiens • / / / / / Halophila engelmanni / / Halophila hawaiiana / / Halophila johnsonii / Halophila minor / / • / /

Halophila ovalis / / / / / / / / / / Halophila ovata Halophila spinulosa Halophila shpulacea / /

Halophila tricostata Phyllospadix iwatensis Phyllospadix laponicus Phyllospadix scouleri / Phyllospadix serrulatus /

Phyllospadix torreyi / Posidonia angustifolia Posidonia australis Posidonia conacea Posidonia denhartogii Posidonia kirkmanii Posidonia oceanica • / Posidonia ostenleldii Posidonia robertsoniae Posidonia sinuosa Syringodium filiforme / / / / Syringodium isoetifolium / / • • • / / / / Thalassia hemprichii // • / Thalassia testudinum • • / / Thalassodendron ciliatum • / / • Thalassodendron pachyrhizum

Zostera asiatica Zostera caespitosa Zostera capensis Zostera capricorni Zostera caulescens Zostera japonica / Zostera marina / / / Zostera mucronata' Zostera muellen'

Zostera noltii / / • / Zostera novazelandica' Zostera tasmanica

TOTAL 4 12 11 3 4 4 5 1 2 2 3 23 11 4 2 12 6 11 4 9

Notes: / indicates presence of a species; indicates a species name no longer used. * * capricorni. Posidonia robertsoniae is conspecific with Posidonia coriacea. Species that are now considered to be conspecific with Zostera

Not including Ruppia spp. Heterozostera tasmanica is now designated Zostera tasmanica. 256 WORLD ATLAS OF SEAGRASSES

Appendix 2: Marine protected areas known to include seagrass beds, by country or territory

Few of these sites are managed directly to support seagrass protection, and in many cases they do not protect the most important areas of seagrass

in a region. Total protected area is given in hectares but this is not indicative of the area of seagrass.

Summary of lUCN management categories - more detailed information at: http://www.unep-wcmc.org/protected_areas/categories/ index.html

Strict Nature Reserve: protected area managed mainly for science

Wilderness Area: protected area managed mainly for wilderness protection

National Park: protected area managed mainly for ecosystem protection and recreation

Natural Monument: protected area managed mainly for conservation of specific natural features

IV: Habitat/Species Management Area: protected area managed mainly for conservation through management intervention

V: Protected Landscape/Seascape: protected area managed mainly for landscape/seascape conservation and for recreation

VI: Managed Resource Protected Area: protected area managed mainly for the sustainable use of natural ecosystems

u/a Unavailable

lUCN management category does not always equate with management effectiveness.

Country Area name Designate Size thai lUCN cat. Year

Anguilla Crocus Bay Marine Park u/a

Sombrero Island Marine Park - u/a

Antigua and Barbuda Cades Bay Marine Reserve u/a 1999

Australia Ashmore Reef National Nature Reserve 58 300 la 1983

Corner Inlet Marine and Coastal Park 18 000 VI 1986

Great Barrier Reef Commonwealth Marine Park 34 480 000 VI 1979

Hinchinbrook Island National Park 39 900 II 1989

Marmion Marine Park 9 500 VI 1987

Ningaloo Marine Park 225 564 VI 1987

Ningaloo Reef Commonwealth Marine Park 232 600 u/a

Rowley Shoals Marine Park 23 250 VI 1990

Shark Bay Marine Park 748 735 VI 1990

Shoalwater Islands Marine Park 6 545 VI 1990

Wilsons Promontory National Park 49 000 II 1898

Bahamas Union Creek Managed Nature Reserve 1813 la 1965

Bahrain Hawar Islands Other area - u/a

Belize Half Moon Cay National Monument 3 925 III 1982

Hoi Chan Marine Reserve 411 IV 1987

Port Honduras Marine Reserve 84 700 IV 2000

South Vi/ater Cay Marine Reserve 29 800 IV 1996

Brazil Abrolhos Marine National Park 91300 II 1983

Fernando de Noronha Marine National Park 11270 II 1988

Saltinho State Forest Reserve 2 10 u/a 1986

British Indian Ocean Diego Garcia Restricted Area - V 1994

Territory

Cambodia Ream National Park 15 000 II 1993

Canada Race Rocks Ecological Reserve 220 la 1980

Cayman Islands Little Sound (Grand Cayman] Environmental Zone 1731 lb 1986

North Sound (Grand Cayman! Replenishment Zone 3310 IV 1986

South Sound (Grand Cayman) Replenishment Zone 317 IV 1986

Spott Bay (Cayman BracI Replenishment Zone 33 IV 1986

China Shan Kou Nature Reserve 8 000 V 1990 Appendix 2 257

Country Area name Designate Size Ihal lUCN cat. Year

Colombia CoralesdelRosanoyde Natural National Park 120 000 II 1977 San Bernardo

Old Providence McBean Natural National Park 995 II 1996 Lagoon

Tayrona Natural National Park 15 000 II 1964

Costa Rica Cahuita National Park U022 II 1970

Gandoca-Manzanillo National Wildlife Refuge 9 4i9 IV 1985

Croatia Briuni National Park 4 660 V 1983 - Cuba Punta France+D225s Parque Nacional Marino MkU II 1985 Punta Pederales

Cyprus Lara-Toxeftra Marine Reserve 650 IV 1989

Dominica Cabrits National Park 531 II 1986

Dominican Republic Del Este National Park 80 800 II 1975

Jaragua National Park 137 400 II 1983

Los Haitises National Park 154 300 II 1976

Montecristi National Park 130 950 II 1983

France Cote Bleue Marine Park 3 070 VI 1982

Golfe du Morbihan Nature Reserve |by Decreel 1500 u/a

Scandola Nature Reserve Iby Decreel 1669 IV 1975

French Polynesia ScillylManuael Territorial Reserve 11300 IV 1992

Germany Sound/Greifswald Wetland Zone of National Importance V 1980

Lagoon/Isle Greifswald

Wismar Bight/Salzhaff area Wetland Zone of National Importance - V 1980

Guadeloupe Grand Guide Sac Mann Nature Reserve 3 736 IV 1987

Guam Guam Territorial Seashore Park 6135 VI 1978

Guatemala Punta de Manabique/ Wildlife Refuge 38 400 u/a

Bahia La Graciosa

Honduras Guanaja Marine Reserve 28 000 u/a

Jeanette Kawas National Park 78162 II 1988

Punta Izopo Wildlife Refuge 11200 IV 1992

India Gulf of Kutch Marine National Park 16 289 II 1980

GulfofKutch Marine Sanctuary 29 303 IV 1980

Gulf of Mannar Marine National Park 623 11 1986

Gulf of Mannar Biosphere Reserve INational) 050 000 VI 1989

Wandur Marine National Park 28150 II 1983

Indonesia Arakan Wowontulap Nature Reserve 13 800 la 1986

Bali Barat National Park 77 727 II 1982

Kepulauan Karimata Nature Reserve 77 000 la 1985

Kepulauan Togian Nature Reserve 100 000 u/a 1989

Pulau Bokor Nature Reserve 15 la 1921

Pulau Rambut Nature Reserve 18 la 1939

Ujung Kulon National Park 122 956 II 1992

Israel Elat Coral Reserve 50 IV - Italy Archipelago Toscano Zona di Tutela Biologica Marina litalyl IV 1982 - Cinque Terre Zona di Tutela Biologica Marina litalyl IV 1982 - Golfo di Portofino Zona di Tutela Biologica Marina (Italy! IV 1982

Miramare Zona di Tutela Biologica Marina litalyl 27 IV 1986

Portofino Regional/Provincial Nature Park 4 660 u/a

Jamaica Discovery Bay Marine Park - u/a

Montego Bay Marine Park 1530 II 1991

Negril Marine Park " u/a 1998 258 WORLD ATLAS OF SEAGRASSES

Country Area name Designate Size Ihal lUCN cat. Year

Jamaica Negril Bay/Bloody Bay- Fisheries Sanctuary - u/a

Hanover FIS

Ocho Rios Protected Area - V 1966

Palisadoes-Port Royal Cays National Park 100 u/a

Kenya Kiunga Marine National Reserve 25 000 VI 1979

Malindi Marine National Park 630 II 1968

Malindi-Watamu Marine National Reserve 17 700 VI 1968

Mpunguti Marine National Reserve 1100 VI 1978

Watamu Marine National Park 12 500 II 1968

Korea. Republic of Nakdong River Mouth Natural Ecological System 3i21 IV 1989

Preservation Area

Madagascar Grand Recif Marine National Park - u/a

Mananara Marine National Park 1000 II 1989

Malaysia Pulau Besar Marine Park 8iU II

Pulau Pertientian Besar Marine Park 9121 II 1999

Pulau Perhentian Kecil Marine Park 8107 II

Pulau Redang Marine Park 12 750 II 1999

Pulau Sibu Marine Park i260 II

Pulau Sipadan Marine Reserve 710 u/a

Pulau Tengah Marine Park 5U9 II

Pulau Tiga Park 15 864 II 1978

Pulau Tinggi Marine Park 10180 II

Pulau Tioman Marine Park 25115 II

Talang-Satang National Park 194U u/a

Tunku Abdul Rahman Park 4 929 II 1974

Turtle Islands Heritage Protected Area 136 844 u/a 1996

Martinique Caravelle Nature Reserve 422 IV 1976

Mauritania Banc d' National Park 1173 000 II 1976

Mauritius Baie de I'Arsenal Marine Marine National Park 100 u/a

National Park

- Balaclava Marine Park II 1997

Flacq Fishing Reserve 600 IV 1983

Port Louis Fishing Reserve 500 IV 1983

Trou d'Eau Douce Fir Fishing Reserve 700 IV 1983

Mexico Arrecifes de Puerto Morelos National Park 10 828 II 1998

Banco Chinchorro Biosphere Reserve (National! 144 360 VI 1996

El Vizcaino Biosphere Reserve INationall 2 546 790 VI 1988

La Blanquilla Other area 66 868 IV 1975

Ria Lagartos Other area 47 840 u/a 1979

Sistema Arrecifal Veracruzano National Marine Park 52 239 II 1992

Monaco Larvotto Marine Reserve 50 IV 1976

Mozambique Bazaruto National Park 15 000 II 1971

llhas da Inhaca e dos Faunal Reserve 2 000 IV 1965

Portugueses

Maputo Game Reserve 90 000 IV 1969

Marromeu Game Reserve 1 000 000 IV 1969

Nacala-Mossuril Marine National Park - lb

Pomene Game Reserve 10 000 IV 1972

Primeira and Segunda Islands National Park - u/a

Zambezi Wildlife Utilization Area 1 000 000 VI 1981 Appendix 2 259

Country Area name Designate Size Iha! lUCN cat. Year

Netherlands Antilles Bonaire fvlarine Park 2 600 u/a 1979

Saba Marine Park 820 u/a 1987

Nicaragua Cayos Misl

Patau Ngerul

Pananna Comarca Kuna Yala ISan BlasI Indigenous Commarc 320 000 u/a 1938

Papua New Guinea Kamiali Wildlife Management Area 47 413 VI 1996

Lou Island Wildlife Management Area - u/a

Maza III Wildlife Management Area 184 230 VI 1978

Motupore Island Wildlife Management Area - u/a

Nanuk Island Provincial Park 12 IV 1973

Talele Islands Provincial Park 40 IV 1973

Philippines St Paul Subterranean River National Park 5 753 II 1971

Tubbataha Reefs National Marine Park 33 200 u/a 1988

t^arine Park

Puerto Rico Boqueron Wildlife Refuge IRefugio de Vida Silvestrel 237 IV 1964

Cayos de la Cordillera Nature Reserve 88 IV 1980

Estuanna Nacional Bahia Jobos Hunting Reserve 1133 IV 1981

Isla Caja de Muerto Nature Reserve 188 IV 1988

Jobos Bay National Estuarine Research Reserve 1168 IV 1981

La Parguera Nature Reserve 4 973 IV 1979

Reunion Cap la Houssaye-Ravine Fishing Reserve - VI 1978

Trois Bassins

lies Glorieuses Nature Reserve - IV 1975

Hot d'Europa Nature Reserve - IV 1975

Pointe de Bretagne-Pointe Fishing Reserve - VI 1978

de I'Etang Sale

Ravine TroisBassins-Pointe Fishing Reserve - VI 1978

de Bretagne

Russian Federation Astrakhansky 66 816 la 1919

Dalnevostochny Morskoy Zapovednik 64 316 la 1978

Kedrovaya Pad Zapovednik 17 900 la 1925

St Lucia fvlaria Islands Nature Reserve 12 IV 1982

Pigeon Island Other area 20 III 1978

Soufriere Marine Management Area VI 1994

St Vincent and Tobago Cays Marine Reserve 3 885 IV 1987

the Grenadines

Saudi Arabia Davtfhat Ad Dafi, DawhatAl- Other area 210 000 u/a

Musallamiyah & Coral Islands

Farasan Islands Protected Area 69 600 la 1989

Seychelles Aldabra Special Nature Reserve 35 000 la 1981

Port Launay Marine National Park 158 II 1979

St Anne Marine National Park 1423 II 1973

Singapore Southern Islands Marine Nature Area 980 u/a 1996

Slovenia Strunjan Landscape Park 192 V 1990

South Africa Agulhas National Park u/a

Cape Peninsula National Park - u/a

Greater St Lucia Wetland Park 258 686 II 1895

Knysna Other area 15 000 u/a

Spain Doriana National Park IState Network! 50 720 II 1969

Ilia de Tabarca Marine Nature Reserve [Spain! 1463 IV 1986

Hies f^ledes Submarine Nature Reserve 418 IV 1983 260 WORLD ATLAS OF SEAGRASSES

Country Area name Designate iize Itial lUCN cat. Year

. Tanzania Bongoyo Island Marine Reserve II 1975

Chumbe Island Coral Park Marine Sanctuary 30 II 1994

ICHICOPI - Fungu Yasini Marine Reserve II 1975

Mafia Island Marine Park 82 200 VI 1995 - Maziwi Island Marine Reserve II 1981 - Mbudya Marine Reserve II 1975

Menai Bay Conservation Area 47 000 VI 1997

Misali Island Conservation Area 2158 VI 1998

Mnemba Conservation Area 15 VI 1997 - Pangavini Marine Reserve II 1975

Thailand Haad Chao Mai National Park 23 086 II 1981

Mu Ko Libong Non-hunting Area «7M III 1979

Tonga Fanga'uta and Fanga Kakau Marine Reserve 2 835 VI 1974 Lagoons

Pangainnotu Reef Reserve 49 IV 1979

Trinidad and Tobago Buccoo Reef Nature Reserve 650 la 1973

Tunisia Icfikeul National Park 12 600 II 1980

Turks and Caicos West Caicos Marine National Park 397 IV 1992

Islands

Ukraine Arabats'kiy State Zakaznik 600 u/a

Karadagskiy Nature Zapovednik lUkrainel 2 874 la 1979

Karkinils'ka zatoka State Zakaznik 27 646 u/a

Kazantypskyi Nature Zapovednik lUkrainel 450 u/a

Molochniy liman State Zakaznik 1900 u/a

Mys Martiyan Nature Zapovednik lUkrainel 240 la 1973

United Kingdom Helford River Voluntary Reserve JUKI u/a 1987

Isles of Scilly Area of Outstanding Natural Beauty lUKl 1 600 V 1976

Skomer National Nature Reserve lUK) 307 IV 1959

Skomer Marine Nature Reserve lUKl 1500 IV 1990

United States Acadia National Park 15 590 II 1919

Apalachicola National Estuarine Research Reserve 99 630 IV 1979

Assateague Island National Seashore 16 038 V 1965

Bafiia Honda State Park 212 V 1961

Biscayne National Park 72 900 II 1980

Breton National Wildlife Refuge 3 661 IV 1904

Cape Cod National Seashore 18018 V 1961

Channel Islands National Park 100 987 II 1980

Channel Islands National Marine Sanctuary 428 466 IV 1980

Chesapeake Bay IMDI National Estuarine Research Reserve 2 374 IV 1981

Chesapeake Bay IVAl National Estuarine Research Reserve 1796 IV 1991

DryTortugas National Park 26 203 II 1992

Everglades National Park 606 688 II 1947

Fire Island National Seashore 7 834 V 1964

Florida Keys Wilderness [Fish and Wildlife Service! 2 508 lb 1975

Galveston Island State Park 786 la

Grand Bay National Estuarine Research Reserve 7 452 IV 1999

Great Bay National Estuarine Research Reserve 2138 IV 1989

Gulf Islands IFloridal National Seashore 54 928 V 1971

Hawaiian Islands 18 sites) National Wildlife Refuge 102 960 la 1945

Izembek National Wildlife Refuge 122 660 IV 1960 Appendix 2 261

Country Area name Designate Size Ihal lUCN cat. Year

United States John Pennekamp Coral Reef State Park 22 68i V 1959

[continuedl Merritt Island National Wildlife Refuge 55 953 IV 1963

Narragansett Bay National Estuarine Research Reserve 1286 IV 1980

Padilla Bay National Estuarine Research Reserve U55 IV 1980

Pinellas National Wildlife Refuge 159 IV 1956

Rookery Bay National Estuarine Research Reserve 5 062 IV 1978

Soutti Slough National Estuarine Research Reserve 1903 IV 1974

St Marks National Wildlife Refuge 26 467 IV 1931

Waquoit Bay National Estuarine Research Reserve 1013 IV 1988

Wells National Estuarine Research Reserve 648 IV 1984

United States Baker Island National Wildlife Refuge 12 843 la 1974

minor outlying islanc

Venezuela Archipielago Los Rogues National Park 221 120 II 1972

Ci Wildlife Refuge 25 723 u/a

Cuare Wildlife Refuge 11825 IV 1972

Laguna de la Restinga National Park 18 862 II 1974

Laguna de Tacarigua National Park 39100 II 1974

Medanos de Coro National Park 91280 II 1974

Mochima National Park 94 935 II 1973

Morrocoy National Park 32 090 II 1974

San Esteban National Park 43 500 II 1987

Viet Nam Con Dao National Park 15 043 II 1982

Virgin Islands IBritishI Little Jost Van Dyke Natural Monument 450 u/a

Norman Island National Park 390 u/a

North Sound National Park 3 800 u/a

The Dogs Protected Area 2 000 u/a

Wreck of the Rhone Marine Park 324 III 1930

Virgin Islands lUSl Green Cay National Wildlife Refuge 6 IV 1977

Salt River Submarine Protected Area 1000 u/a

Canyon NHS

Sandy Point National Wildlife Refuge 134 IV

St James Marine Reserve and Wildlife banctuar> - u/a 1994

Virgin Islands National Park 5 308 II 1956 .

262 WORLD ATLAS OF SEAGRASSES

Appendix 3: Species range maps

The range maps have been created to establish a guide to where individual However, published results of genetic testing and analysis of

seagrass species might be expected to occur Range boundaries were morphological characteristics shared by species within the complex have

drav«n to encompass all points where there was sufficient documentation shown that Posidonia conacea and Posidonia robertsoniae are not

to determine the occurrence of a seagrass species in a location. It is separate species'"; they are treated as Posidonia conacea here, fvlore

possible that seagrass species occur beyond the ranges shown since not genetic research is needed in order to re-evaluate and define the complex

all areas have been adequately surveyed. In some instances, isolated as a whole'". Without publication of conclusive information, we have

observations of species occurrence were marked as distinct entries. continued to view the species separately but realize that the complex is

Range maps were not prepared for Ruppia species as the existing data likely to contain conspecific species.

were deemed insufficient. The species range maps update earlier work by

den Hartog'" and by Phillips and Ivlenez"'. Estimates of species range area Halodule spp. complexes

are given with each map. The most recent genetic analysis indicates that two major groups of

Morphological differences In seagrass plants have led to some Halodule exist'". The Atlantic Halodule spp. complex consists of Halodule

confusion regarding species designation, and several species are now wnghtii Ascherson. Halodule beaudettei Iden Hartogl den Hartog and

being revised based on genetic and morphometric research. Two recent Halodule bermudensis den Hartog. The three species are distinguished

species revisions have been made which combine identified conspecific by leaf tip morphology However, some researchers have suggested that

species (see Habphita ovalis and Zostera capncorni, belowl; revised leaf morphology changes under different environmental conditions'".

species range maps have been included. The species range maps for Further genetic studies and/or common garden experiments are needed.

species formerly accepted have also been included to make a connection The Indo-Pacific Halodule species, consisting of Halodule uninervis

with the literature documenting these species distributions. Several IForsskall Ascherson and Halodule pimlolia (fvlikil den Hartog, are

other species designations remain a matter of debate and are currently suggested to be conspecific in unpublished genetic studies. These results

under genetic and morphometric investigation. Closely linked species indicate that Halodule uninervis is the only Halodule species in the Pacific

that may actually be conspecific have often been grouped together in a and Indian Oceans, except in eastern Africa and India where Halodule

complex while additional research is undertaken. These species do not wnghtii IS also found. Without conclusive published information, we

have adjusted range maps, but descriptions of the Posidonia ostenfeldii present the Halodule species separately but realize that both complexes

complex and the Halodu/espp. complexes are included below. are likely to contain conspecific species.

Halophila ovalis revision References

A group of Halophila species found around the world have recently 1 den Hartog C 119701. The Sea-6rasses of f/ie IVor/d. North Holland

received detailed genetic evaluation. Four species, Halophila phnsonii Publishing Co.. Amsterdam. 275 pp.

Eiseman from the east coast of Florida, Halophila hawaiiana Doty and 2 Phillips RC, fvleriez EG [1988). Seagrasses. Smithsonian

Stone from Hawaii. Halophila ovata Gaudichaud from the Indo-Pacific and Contributions to the fvlarine Sciences 34. Smithsonian Institution

Halophila minor IZollingerl den Hartog, were all determined to be Press, Washington DC.

morphological variations of, and therefore conspecific with, Halophila 3 Waycott M. Freshwater DW, York RA, Calladme A, Kenworthy. WJ [20021.

ovalis IR. Brown] Hooker f."'. Range maps are presented for each former Evolutionary trends in the seagrass genus Halophila IThouarsI: insights

species individually as well as for the newly redefined Halophila ovalis. from molecular phytogeny Bulletin of Marine Science

i Les DH, Moody ML, Jacobs SWL, Bayer RJ [2002]. Systematics of

Zostera capricorni revision seagrasses IZosleraceael in Australia and New Zealand. J Sys

Zostera novazelandica Setchell and Zostera capricorni Ascherson in New Botany 27. iii-m.

Zealand are conspecific. based on detailed genetic and morphometric 5 Kuo J, Cambridge ML [1984]. A taxonomic study of the Posidonia

analysis'". From the same analysis, the Australian species Zostera muellen ostenfeldii complex IPosidoniaceael with description of four new

Irmisch ex. Aschers. and Zostera mucronata den Hartog are also Australian seagrasses. Aquatic Botany 20: 267-295,

considered to be conspecific with Zostera capncorni. We have included b Campey ML, Waycott M. Kendrick GA [2000]. Re-evaluatmg species

Zostera novazelandica and Zostera capricorni on the same range map. boundaries among members of the Posidonia ostenfeldii spec\es

Zostera muelleh and Zostera mucronata ate displayed separately Range complex IPosidoniaceael - morphological and genetic variation.

maps are presented for former species individually as well as for the newly Aquatic Botany 6i. 41-56.

redefined Zostera capricornt'' 7 Waycott M. Personal communication.

8 McMillan C, Williams SC, Escobar L, Zapata (19811. Isozyymes.

Posidonia osfenfe/dii complex secondary compounds and experimental cultures of Australian

In the case of the Posidonia ostenfeldii complex, new genetic testing seagrasses in Halophila. Halodule. Amphibolis. and Posidonia. Aust

suggests that some of the species are conspecihc. The complex consists J 6(3(29:247-260.

of five species: Posidonia ostenfeldii den Hartog, Posidonia denhartoqii

Kuo & Cambridge, Posidonia robertsoniae Kuo & Cambridge. Posidonia In the maps below, ' indicates species designations that are a matter of

conacea Cambridge & Kuo and Posidonia kirkmanii Kuo & Cambridge'". debate and currently under genetic and morphometric investigation. Appendix 3 263

Family Hydrocharitaceae

(3 genera)

Genus Enhalus L.C. Richard (1 species)

Dioecious robust perennial with creeping, coarse unbranched or sparsely monopodiaily branched rhizomes with short internodes. Fleshy thick roots are unbranched, Male inflorescence has a short stalk and a 2-bladed spathe surrounding many flowers that break off and release pollen to float on the surface of the water There are 3 sepals,

3 petals and 3 stamens. Female inflorescence with a long stalk and a 2-bladed spathe containing 1 large flower.

There are 3 sepals and 3 petals. The ovary is rostrate, composed of 6 carpels and 6 styles, and is forked from the base. The stalk of the female flower coils and contracts after anthesis. Fruits are fleshy. Leaves are distichously arranged and sheathed at the base; persistent fibrous strands from previously decayed leaves enclose the stem.

Leaf apex rounded.

Enhalus acoroides

Enhalus acoroides ^""^^

•*

h.t'-

MAP 1: Enhalus acoroides [LA.] Royle (Hydrocharitaceae)

Shaded area = 5 005 000 km", actual species distribution is much less

Genus Halophila Jhouars [M species)

Monoecious and dioecious small, fragile plants with long internodes on rhizomes each bearing 2 scales and a

lateral shoot. Each node has 1 unbranched root. Single inflorescence covered by 2 spathal bracts. Male flowers have short stalks, 3 tepals, 3 stamens, sessile anthers and pollen grams in ellipsoid chains. Female flowers are sessile,

have 3-6 styles, and ellipsoid to globular fruit that hold numerous globular seeds. Leaves are either distichously arranged along upright shoot, in pairs on long petioles or as pseudo-whorls at top of lateral shoots. Leaves have ovate, elliptic, lanceolate or linear blades with 1 mid-vein and intramarginal veins linked by cross-veins. Leaf

margins smooth or serrate, with leaf surface smooth or hairy.

Habphila australis. Halophila baillonii, Habphila beccarii, Halophila capricorni, Halophila decipiens, Halophila

engelmanni, Halophila hawaitana, Halophila johnsonn, Halophila minor, Halophila ovalis. Halophila ovata,

Halophila spinulosa, Halophila stipulacea. Halophila tncostala 264 WORLD ATLAS OF 5EAGRAS5ES

Halophila australis

I > /

^ ]

MAP 2: Halophila australis Doty & Stone (Hydrocharitaceae)

Shaded area = Hi 000 km', actual species distribution is much less

Halophila baillonii

MAP 3: Halophila baiUonii Ascherson (Hydrocharitaceae)

Shaded area = 139 000 km'', actual species distribution is much less

Halophila beccarii

MAP 4: Halophila beccarii Ascherson (Hydrocharitaceae)

Shaded area = 1511 000 km', actual species distribution is much less Appendix 3 265

Halophila capricorni

f t-

MAP 5: Halophila caprlcorni Larkum (Hydrocharitaceae)

Shaded area = 269 000 km', actual species distribution is much less

Halophila decipiens

MAP 6: Halophila dedp/ens Ostenfeld (Hydrocharitaceae)

Shaded area = 7 702 000 km\ actual species distribution is much less

Halophila engelmanni

MAP 7: Halophila engelmanni Ascherson (Hydrocharitaceae)

Shaded area = 725 000 km', actual species distribution is much less 266 WORLD ATLAS OF SEAGRASSES

Halophila hawaiiana

.^m- \ \

MAP 8: Halophila hawaiiana Doty & Stone (Hydrocharitaceae)

Shaded area = 7 000 km', actual species distribution is much less

Note: Halophila hawaiiana is now conspecific with Halophila ovali^'[

Halophila johnsonii

MAP 9: Halophila johnsonii Eiseman (Hydrocharitaceae)

Shaded area = 12 000 km', actual species distribution is much less

Note: Halophila lohnsonii is now conspecific with Halophila ovali^'\

Halophila minor

MAP 10: Halophila minor [Zollinger] den Hartog (Hydrocharitaceae)

Shaded area = 3 761 000 km', actual species distribution is much less

Note: Halophila minor is now conspecific with Halophila oralis"^'. Appendix 3 267

Halophila ovalis

MAP 11: Halophila ovalis (R. Brown) Hooker f. (Hydrocharitaceae)

Shaded area = 7 6U 000 km", actual species distribution 15 much less

Note: Map represents the range of the former Halophila ovalis, before its current revision. See Msp 12

Halophila ovalis revision

MAP 12: Halophila ovalis revision

Shaded area = 7 633 000 km', actual species distribution is nnuch less

Note: Halophila johnsonii, Halophila hawaiiana. Halophila m/norand Halophila ovata are now considered to be

conspeciiic with Halophila ovali^^'. The range map presented here is for the newly redefined Halophila ovalis.

Halophila ovata

MAP 13: Halophila ovata Gaudichaud (Hydrocharitaceae)

Shaded area = 3 186 000 km', actual species distribution is much less

Note: Halophila ovata is now conspecific with Halophila ovalis"'. 268 WORLD ATLAS OF SEAGRASSES

Halophila spinulosa

MAP 1A: Halophila spinulosa (R. Brown) Ascherson (Hydrocharitaceael

Shaded area = 3 796 000 km', actual species distribution is much less

Halophila stipulacea

MAP 15: Halophila stipulacea (Forsskal) Ascherson (Hydrocharitaceael

Shaded area = 924 000 km', actual species distribution is much less

Halophila tricostata

MAP 16: Halophila tricostata Greenway (Hydrocharitaceael

Shaded area = 415 000 km', actual species distribution is much less Appendix 3 269

Genus Thalassia Banks ex Konig (2 species)

Dioecious perennial with creeping rhizomes that have many small internocjes and 1 scale leaf at each node. At

intervals there are 1 or more unbranched roots and a short erect stem with 2-6 leaves. Male flowers have a short

stalk, 3 perianth sections. 3-12 light yellow stamens and globular pollen grains linked into chains. Female flowers

also have 3 perianth segments with 6-8 styles each split into 2 lengthy stigmata. Fruit is prickly and spherical with

a fleshy pericarp that splits into non-uniform valves, releasing pear-shaped seeds with membranous testa. Seeds

germinate immediately The linear leaf blade, sometimes slightly bowed, has 9-17 longitudinal veins and a round,

finely serrulated apex. Tannin cells are present but stomata are not.

Jhslassia hempnchii, Thalassia testudinum

- -' .^ Thalassia hemprichii

'"'

1

' -w ^' ^ '' .''

^^' ' f~^,' .i -J^^^^B* Wumf MAP 17: Thalassia hemprichii lEhrenberg) Ascherson (Hydrocharitaceae)

Shaded area = 6 094 000 km', actual species distribution is much less

Thalassia testudinum

MAP 18: Thalassia testudinum Banks ex Konig (Hydrocharitaceae)

Shaded area = 1 165 000 km', actual species distribution is much less 270 WORLD ATLAS OF SEAGRASSES

Family Cymodoceaceae (5 general

Genus Amphibolis C. Agardh (2 species)

Dioecious perennial with woody sympodially branched rhizomes. 1-2 wiry but abundantly branched roots at each

node. Nodes nnay have long, thin abundantly branched stitf stems with crown leaves on each branch. The singular,

terminal flowers are enclosed by several leaves. Male flowers have 2 anthers connected at the same height to a

short stalk. Female flowers are sessile with 2 free ovaries, each with a short style spilt into 3 long stigmata with

pericarpic lobes at each ovary base. Seedlings are viviparous and have comb-shaped structures extending from

the pericarpic lobes that act as anchors. Leaf sheaths shed leaving circular scar on the erect stems. The linear

leaf blade has 8-21 longitudinal veins and a bidentate apex.

Amphibolis antarctica, Ampliibolis gnlfithii

Amphibolis antarctica

MAP 19: Amphibolis antarctica (Labill.) Sonder et Ascherson (Cymodoceaceae)

Shaded area = 535 000 km', actual species distribution is much less

Amphibolis griffithli

MAP 20: Amphibolis griffithii [Black] den Hartog (Cymodoceaceae)

Shaded area = 330 000 km"', actual species distribution is much less Appendix 3 271

Genus Cymodocea Konig [i> species) with Dioecious perennial with creeping herbaceous monopodially branched rhizomes. 1 to several branched roots

a short stiff stem bearing 2-7 leaves found at each node. Stalked male flower has 2 anthers connected at same

height on stalk. Female flowers are sessile with 2 free ovaries each with a short style that splits into 2 long 7-17 stigmata. Fruit are semi-circular to elliptical shaped with a solid pericarp. The linear leaf blade has

longitudinal veins and smooth margins. Apex rounded, sometimes notched or serrate. Leaf sheaths shed leaving

circular scar on erect stems.

Cymodocea angustata, Cymodocea nodosa, Cymodocea rotundata, Cymodocea serrulata

Cymodocea angustata

MAP 21: Cymodocea angustata Ostenfeld (Cymodoceaceae)

Shaded area = 160 000 km", actual species distribution is much less

Cymodocea nodosa

MAP 22: Cymodocea nodosa lUcrial Ascherson (Cymodoceaceae)

Shaded area = 610 000 km', actual species distribution is much less 272 WORLD ATLAS OF SEAGRASSES

k--. 'xy^^^ - ---,w -'J' K Cymodocea rotundata

^"^"^^W

;.\ ^r',---

MAP 23: Cymodocea rotundata Ehrenberg & Hemprich ex Ascherson (Cymodoceaceael

Shaded area = 5 323 000 km', actual species distribution is much less

Cymodocea serrutata

MAP 2i: Cymodocea serrulata (R. Brown) Ascherson ICymodoceaceaej

Shaded area = 5 578 000 km', actual species distribution is much less

Genus Halodule Endlinger (6 species)

Dioecious perennial with creeping herbaceous monopodialiy branched rhizomes. 1 or more unbranched roots and

a short erect stem with 1-4 leaves found at each node. The singular, terminal flowers are enclosed by a leaf.

Stalked male flower has 2 anthers connected at same height on stalk. Female flowers have 2 free ovaries each

with a long, continuous and undivided style. Fruit has stony, solid pericarp. Leaf sheaths shed leaving circular scar

on the stems. The linear leaf blade has 3 longitudinal veins and a variable apex shape. The genus has 2 species

in the Pacific and 4 species in the Atlantic, all largely distinguished by leaf tip morphology.

Halodule beaudettei. Halodule bermudensis. Halodule emarginata, Halodule pinifolia, Halodule uninervis,

Halodule wnghtii Appendix 3 273

Halodule beaudettel*

MAP 25: Halodule beaudettel* (den Hartog) den Hartog iCymodoceaceae)

Shaded area = 74 000 km', actual species distribution is mucti less

Halodule bermudensis*

MAP 26: Halodule bermudensis* den Hartog ICymodoceaceae)

Shaded area = 1 000 km', actual species distribution is much less

Halodule emarginata*

MAP 27: Halodule emarginata* den Hartog ICymodoceaceae)

Shaded area = U1 000 km', actual species distribution is much less 274 WORLD ATLAS OF SEAGRA5SE5

Halodule pinifolia*

MAP 28: Halodule pinifolia*W\k\] den Hartog iCymodoceaceae)

Shaded area = 5 580 000 km', actual species distribution is much less

Halodule uninervis*

MAP 29: Halodule uninervis* (Forsskal) Ascherson ICymodoceaceae)

Shaded area = 6 73i 000 km', actual species distnbutioti is much less

Halodule wrightii

MAP 30: Halodule wrightii Ascherson ICymodoceaceae)

Shaded area = 2 625 000 km', actual species distribution is much less Appendix 3 275

Genus Syringodium Kiitzing (2 species)

Dioecious perennial with creeping herbaceous monopodially or sympodially branched rhizomes. Rhizomes with

1-4 little branched roots and an erect shoot bearing 2-3 round leaves at each node. Inflorescence cymose. flowers

are encompassed by a reduced leaf. Stalked male flower has 2 anthers connected at same height on stalk. Female

flowers have 2 free ovaries each with a short style and 2 short stigmata. Fruit has stony, solid pericarp. Leaf

sheaths shed leaving circular scar on the rigid stems. Round leaf blades tapering to the tip.

Syringodium liliforme, Syringodium isoetifolium

Syringodium filiforme

MAP 31: Syringodium filiforme Kiitzing (Cymodoceaceae)

Shaded area = 1 174 000 km', actual species distribution is much less

Syringodium isoetifolium

MAP 32: Syringodium isoetifolium (Ascherson) Dandy (Cymodoceaceae)

Shaded area = 5 919 000 km*, actual species distribution is much less 276 WORLD ATLAS OF SEAGRASSES

Genus Thalassodendron den Hartog (2 species)

Dioecious perennial with woody sympodially branched rhizomes. 1 or more robust, woody, little branched roots

occur at the nodes preceding the erect stem-bearing nodes. From every fourth node there are long, wiry

infrequently branched stems each bearing crown leaves. Single flowers grow at the end of the stem and are

enclosed by several bracts. Male flowers with 2 anthers connected at the same height to the stalk. Female flowers

are sessile with 2 free ovaries, each with a short style split into 2 stigmata. Seedlings are viviparous. Leaf sheaths

shed leaving circular scar on the erect stems. The linear leaf blade has 13-27 longitudinal veins and the margin

and rounded apex are finely denticulate.

Thalassodendron ciliatum. Thalassodendron pachyrhizum

Thalassodendron ciliatum

MAP 33: Thalassodendron ciliatum (Forsskil) den Hartog (Cymodoceaceae)

Shaded area = i 087 000 km*', actual species distribution is much less

Thalassodendron pachyrhizum

MAP 34: Thalassodendron pachyrhizum den Hartog (Cymodoceaceae)

= Shaded area 1 U 000 km', actual species distribution is much less Appendix 3 277

Family Posidoniaceae

(1 genus)

Genus Posidonia Kbnig (8 species!

Monoecious perennial with creeping, monopodially branching rhizomes with 1-2 branched or unbranched roots

and a shoot. Inflorescence racemose with many barbs. Flowers are hermaphroditic, have 3 stamens but no

perianth. Stigma are disc-shaped with inconsistent lobe shapes. Stone fruit with fleshy pericarp. Pericarp splits to

release oblong seeds with membranous testa. Leaves are distichous, ligulate and auriculate with a distinct sheath

and blade. The leaf sheath is persistent and frequently breaks into fibrous strands covering rhizome internodes.

The leaf blade is either flat and biconvex or terete and linear with 5-21 longitudinal veins and apex obtuse or

truncate.

Posidonia angustifolia. Posidonia australis, Posidonia conacea lincludes conspecific Posidonia roberlsoniae],

Posidonia denharlogii, Posidonia kirlananii, Posidonia oceanica. Posidonia oslenfeldii. Posidonia sinuosa

Posidonia angustifoUa

MAP 35: Posidonia angustifoUa Cambridge & Kuo (Posidoniaceae)

Shaded area = 284 000 km", actual species distribution 15 much less

Posidonia australis

MAP 36: Posidonia australis Hooker f. (Posidoniaceae)

Shaded area = 600 000 km', actual species distribution is much less 278 WORLD ATLAS OF SEAGRASSES

Posidonia coriacea*

MAP 37: Posidonia coriacea* Cambridge & Kuo IPosidoniaceae)

Shaded area = 32i 000 km", actual species distribution is much less

Note: Posidonia robertsoniae has been combined with Posidonia conacea as recent research'" suggests they are

conspecific.

Posidonia denhartogii*

MAP 38: Posidonia denhartogii* Kuo & Cambridge IPosidoniaceae)

Shaded area = 137 000 km", actual species distribution is much less

Posidonia l(irl

MAP 39: Posidonia l(irl

Shaded area = 66 000 km', actual species distribution is much less Appendix 3 279

Posidonia oceanica

MAP AO: Posidonia oceanica (L.) Delile (Posidoniaceael

Shaded area = 533 000 km', actual species distribution is mucti less

Posidonia ostenfeldii*

MAP 41: Posidonia ostenfeldii* den Hartog (Posidoniaceael

Shaded area = 66 ODD km', actual species distribution is much less

Posidonia sinuosa

MAP A2: Posidonia sinuosa Cambridge & Kuo I Posidoniaceael

Shaded area = 266 000 km', actual species distribution is much less 280 WORLD ATLAS OF SEAGRASSES

Family Zosteraceae (2 genera)

Genus Zostera L. (9 species)

Monoecious perennial (sometimes annual! that has creeping herbaceous rhizomes with 1 to several roots and 1

shoot with 2-6 leaves. Tannin cells absent; stomata absent. The inflorescence shoots show sympodial branching;

the spathe is stalked and bears alternate male and female flowers in 2 rows on the spadix without perianth. The

retinacula can be present or absent. Pollination hydrophilous. The fruit is ovoid to ellipsoid. The leaf blade is

linear, flattened, with 3-1 1 longitudinal veins. The apex shape is variable and the sheath can be open or closed.

Zostera asiatica, Zostera caespitosa, Zostera capensis, Zostera capncorni (includes the conspecific Zostera

mucronata, Zostera muelten and Zostera novazelandica], Zostera cautescens, Zostera japonica. Zostera manna,

Zostera noltii. Zostera tasmanica (formerly Heterozostera tasmanica]

Zostera asiatica

MAP 43: Zostera asiatica MikI (Zosteraceae)

Shaded area = 1 3) 1 000 l

Zostera caespitosa

MAP 44: Zostera caespitosa Miki (Zosteraceae)

Shaded area = W5 000 km', aclual species distribution is much less Appendix 3 281

-J»P—5;^ Zostera capensis

MAP 45: Zostera capensis Setchell (Zosteraceae)

Shaded area = 363 000 km', actual species distribution is mucti less

Zostera capricorni

MAP A6: Zostera capricorni Ascherson (Zosteraceae)

Stiaded area = 5i3 000 km', actual species distribution is much less

Notes: Zostera novazelandica Setchell is now considered to be conspecific with Zostera capncorni.. The two show complete overlap of occurrence in New Zealand. Zostera mueWen and Zostera mucmnata are also now considered to be conspecific with Zostera Capricorn/^'.

Zostera capricorni revision

MAP 47: Zostera capricorni revision

Shaded area - 773 000 km', actual species distribution is much less

Note: Zostera mucronata. Zostera muelten and Zostera novazelandica are now considered lo be conspecific with

Zostera capncorni"'\ The range map presented here is for the newly redefined Zostera capricorni. 282 WORLD ATLAS OF SEAGRASSES

Zostera caulescens

MAP 48: Zostera caulescens Miki (Zosteraceael

Shaded area = M2 000 km*', actual species distribution is much less

Zostera japonica

MAP 49: Zostera japonica Aschers. & Graebner (Zosteraceael

Shaded area = 2 819 000 km"', actual species distribution is much less

Zostera marina

MAP 50: Zostera marina Linnaeus (Zosteraceael

Shaded area = 5 738 000 km', actual species distribution is much less Appendix 3 283

Zostera mucronata

MAP 51: Zostera mucronata den Hartog IZosteraceael

Shaded area = 1 16 000 km', actual species distribution is much [ess

Note: Zostera mucronata is now considered to be conspecific with lostera capncorni'''\

Zostera muelleri

MAP 52: Zostera muelleri \rm\sch ex Aschers. (Zosteraceae)

Shaded area = 1 W 000 km', actual species distribution is much less

Note: Zostera muelleri is now considered to be conspecific with Zostera capricorni "'.

Zostera noltii

MAP 53: Zostera no

Shaded area = 1 571 000 km', actual species distribution is much less 284 WORLD ATLAS OF SEAGRASSES

Zostera tasmanica

MAP 54: Zostera tasmanica (Martens ex Aschers.) den Hartog IZosteraceae)

Shaded area = i79 000 knr, actual species distribution is much less

Note: Formerly Heterozostera tasmanica'".

Genus Phyllospadix Hooker (5 species)

Dioecious perennial with creeping herbaceous rhizomes bearing 2 to several short unbranched roots and 1 leaf at

each node. The spathe is stalked and bears alternate male and female flowers in 2 rows on the spadix. The

retinacula is present. Fruit are crescent-shaped and have lateral arms with hard bristles. The leaf blade is linear,

flattened, subterete, sometimes leathery, sometimes rolled, with 3-7 longitudinal veins. The apex shape is

variable and the sheath is open.

Phyllospadix iwatensis, Phyllospadix japonicus, Phyllospadix scouleri. Phyllospadix serrulatus, Phyllospadix

torreyi

Phyllospadix iwatensis

MAP 55: Phyllospadix iwatensis Makjno (Zosteraceae)

Shaded area = 722 000 km', actual species distribution is much less Appendix 3 285

Phyllospadix japonicus

MAP 56: Phyllospadix japonicus Makino (Zosteraceael

Shaded area = 248 000 km', actual species distribution is much less

Phyllospadix scouleri

MAP 57: Phyllospadix scouleri Hooker IZosteraceae)

Shaded area = 263 000 knr', actual species distribution is much less

Phyllospadix serrulatus

MAP 58: Phyllospadix serrulatus Ruprecht ex Aschers. IZosteraceae)

Shaded area = 363 000 km', actual species distribution is much less 286 WORLD ATLAS OF SEAGRASSES

Phyllospadix torreyi

MAP 59: Phyllospadix torreyi S. Watson (Zosteraceae)

Shaded area = 181 000 km', actual species distribution is much less

Family Ruppiaceae

(1 genus)

Genus Ruppia (4 marine species)

Dioecious annual or perennial with monopodially branched rhizonnes and 1-2 unbranched roots per node. Root

hairs abundant. Inflorescence a spike of 1-2 flowers on opposite faces of the axis, enclosed at first in the inflated

sheath. Peduncle short, stout, erect or elongating greatly before anthesis to a fine thread raising the flowers to

the water surface and becontiing tightly spirally coiled, retracting the developing fruits. Pollination either on or

below the water surface. Fruit is a fleshy drupe on a long stalk. Leaves alternate (except the 2 immediately below

the flower which are sub-oppositel, sheath open, edges overlapping. Blade narrow-linear to filiform, more or less

concavo-convex with a large air canal either side of an inconspicuous median vein. Tannin cells present in most

tissues.

Ruppia cirrhosa, Ruppia mantima, Ruppia megacarpa, Ruppia tuberosa

Range maps were not prepared for Ruppia species as the existing data were deemed insufficient,

Acknowledgement

We are grateful to tfie following sources for the information on genera taxonomy given in this appendix:

Kuo J, den Hartog C [20011. Seagrass taxonomy and identification key In: Short FT, Coles RG ledsl Global Seagrass Research Methods. Elsevier Science, Amsterdam, pp 31-58.

Womersley HBS [1984]. The Marine Benthic Flora of Southern Australia. Part 1. DJ Woolman, Government

Pnnter, South Australia. 329 pp.

den Hartog C [1970]. The Sea-Grasses of the World. North Holland Publishing Co., Amsterdam. 275 pp. Global Seagrass Workshop 287

THE GLOBAL SEAGRASS WORKSHOP including seagrass distribution and diversity maps based The Global Seagrass Workshop was organized and on an extensive literature search, framed much of the

convened by UNEP-WCMC, with considerable assistance discussion at the workshop. Delegates debated the map

fronn the World Seagrass Association, in St Petersburg. results and marked corrections. A standard species list Florida. USA on 9 November 2001. Twenty-three was agreed upon and information on economic value, delegates (see photograph] from 15 countries prepared uses and threats, associated species and management

discussion papers for their areas of expertise, and a interventions was shared. The workshop ended with a

further five papers were received from people unable to discussion of global priorities for seagrass research and

attend (see map). policy and a commitment by all delegates to contribute a

A preliminary study prepared by UNEP-WCMC. regional chapter to this World Atlas.

Delegates at the Global Seagrass Workshop. From left, front row: Caroline Ochieng. Mark Spalding, Fred Short, Michelle Taylor, Hitoshi lizumi. Second row: Evamaria Koch, Chatcharee Supanwanid, Graeme Inglis, Joel Creed, Nataliya Milchakova, Salomao Bandeira. Third row;

Paul Erftemeijer, Rob Coles, Tanaji Japtap, Miguel Fortes, Diana Walker, Hugh Kirkman, Jorge Herrera-Silveira, Japar Sidik Bujang . Back row: Kun-Seop Lee, Ron Phillips, Andrea Raz-Guzman, Sandy Wyllie-Echeverria.

Map showing the location of all delegates at the Global Seagrass Workshop IcirclesI, and other regions for which papers were prepared

Itrianglesl. 1

288 WORLD ATLAS OF SEAGRASSES

Index to THE WORLD ATLAS OF SEAGRASSES

Page references in bold refer to Andaman Sea 144-50 Asterina pancera 51 figures in tfie text; ttiose in italics 251 Atlantic Ocean see mid-Atlantic refer to tables or boxed material Anguilla 251. 256 region; North Atlantic Anguilla anguilla 33 Australia animal fodder 61, 62 associated species 11 annual populations 121 endemic species 12, UO. 117

antibiotics 1 14 Northern Territory 1 1 Abrolhos Bank, Brazil 2i3, 247 antifouling compounds 114 policies and protection 23 Abu Dhabi Emirate 74. 78. 80 Antigua and Barbuda 238, 251. 256 seagrass species 251

Acanthopagrus schlegeii 196 Antilles, Netherlands 253. 259 southern coast 9, 122, 128 Acanthophora 235 Aplysia punctata 40 see also Eastern Australia;

adaptations of seagrasses 5 Apseudes chilkensis 1 75 Western Australia Adriatic Sea 50. 52 Aqaba [Elatl, Gulf of 67, 68-9, 70-1, 74 Austrovenus stutchburyi 135 Aegean Sea 65, 67, 68, 71, 72 aquaculture Avon-Heathcote Estuary, New Africa see East Africa; South Africa; fish 114, 154, ;5S, 213 Zealand 135 137. 138, 139-40 West Africa seaweeds 87-8, 176, 197 Aythya amencana 228 agriculture shellfish 43, 154, 197,205,213 Azerbaijan 62, 251 as threat to seagrasses 99, 130 Arabian Gulf Azov Sea 59.61-2 uses of seagrasses 61, 62, 188, 197 biogeography 74-8 aircraft runways 164-5, 166 policy and management 80 Akkeshi. Hokkaido 187. 189 seagrass distribution 78 Al Iskandariya (Alexandria! 66-7 threats and seagrass losses 78, 80 B Alabama 225 turtles and dugong 79 Bagamoyo. Tanzania 87 Aland Islands. Finland 29. 30 Arabian Sea 75 Baguala Bay. Indonesia 179 Alaska 199-204 Aral Sea 59, 61,63 Bahamas 251. 256 Albermarle Sound. North Carolina Aransas Bay, Texas 227 Bahia de Chengue, Colombia 239 218 Arenicola manna 44 Bahrain 74, 75, 78, 80, 251. 256

Alexandria 66-7 Argentina /4. 246 causeway 6. 76 Alfacs Bay, Spain 54 Argopecten irradians 209-10, 216 Baja California 199. 201 algae see epiphytic algae; Argopecten purpuratus 246 Balearic Islands 53 filamentous algae; macroalgae; ark shell 97 Baltic Sea 28-30. 33. 34. 35 phytoplankton Aru Islands. Indonesia 179 Bangka. Indonesia 178 Algeria 251 associated biota 10-12 Bangladesh 251 alien species 49-50. 114. 203-4. 205 Brazil 244. 245 banknote. Brazilian 249 macroalgae 55. 68, 69, 71, ;55 Caribbean 235-6 "banquette" 53 seagrasses 114, 203-4 East Africa 83. 85 Banten Bay. Indonesia 175-6. 178.

Amami Islands, Japan 186 endangered/threatened /2. 17. 40. 180 Amblygobius albimaculatus 96 183 Barbados 251 Ambon Bay, Indonesia 179 India 101-2. 105. 107 Barbatia fusca 97 Ammonia 175 Indonesia 174-80 Barnegat Bay. New Jersey 209. Amphibolis antarctica 113. 117. 122, major taxonomic groups 11 210 251-5. 270 Mediterranean 51 bass, striped 209 Amphibolis griffithii 251-5. 270 migratory movements 235 Batophora 235-6

Amphiroa fragilissima 1 55 New Zealand 134-5. UO bay scallop 209-10, 216 Anambas Island, Indonesia 178 north western Atlantic 209-10 beach cast material 86, 88-9 anchor damage 43, 204, 247 Philippines and Viet Nam 183 beach seines 148-9 Andaman and Nicobar Islands 101. Scandinavia 27, 28,30 Belitung, Indonesia 178

102-3. 704. 105 western Europe 40 Belize 14. 236. 237, 239, 251. 256 Index 289

Benoa Bay, Indonesia 178 Christchurch, New Zealand 137, 138 Bermuda 251 Christmas Bay, Texas 227 biodiversity Chrysochromulina 31

centers of 9, 10, 185 Calcanna calcar 1 75 Chwaka Bay, Tanzania 85, 86

in seagrass ecosystems 10-12, 17 Catlinectes sapidus 216, 245-6, 248 Cladophora 60, 61

seagrasses 9, 22 Callophytlis rhynchocarpa 197 Cladophora glomerata 33 biogeograplnic patterns 9-10 Calotomus carolinus 85-6 clam worms 213 biomass 16 Calotomus spinidens 96, 97 clams 246 Baltic Sea 28 Cambodia 251, 256 dredgingfor43-4, 219, 220-7 below-ground 172 Canada hand digging 43, 212, 213 Gulf of Mexico 231-2 Atlantic coast 207. 212 soft-shell 275 India lOi 207. 212 Clean Water Act lUSI 220 Indonesia 172-3 marine protected areas 256 climate change 167, 191, 241 Japan 187 Pacific coast 199-204 potential response of seagrasses Zostera 196 seagrass species 251 17,85 birds 40, U1, 189. 199, 200. 210, 228. Cape Cod 208, 210 coastal development 245 Cape Lookout, North Carolina 218 Arabian region 76, 78, 80 Biscay, Bay of 45 capybara 245 Caribbean 238-9, 241 bivalves carbon cycle 17, 84. 85 Japan 188-9

digging/dragging for 98, 99, 1 57, carbon dioxide levels 85 Malaysia 157

158.2)0. 2^2. 213 Caribbean 9, 234-41 Mediterranean 55

dredging for 43-4, 219, 220-1 ecosystem description 235-8 northeastern United States 27 7 East Africa 83, 85 historical perspectives 238 Pacific islands 161 endemic 140 policy and protection 241 South America 246-7 Malaysia 157, 158 species and coverage 234-5, 238 Western Australia 112 New Zealand 135, 140 threats to seagrasses 238-9, 241 western Pacific islands 165, 166-7 protected 51 see also named islands see also land reclamation western Europe 40, 43-4 Caribbean Coastal Marine coastal management western north Atlantic 209-10, 212, Productivity [CARICOMPI network East Africa 89-90 213 239. 241 rapid assessment technique 77 black brant 200 CARICOMP network 239, 241 coastal protection 17, 86-7, 88-9

Black Sea 59-61 Carpentaria, Gulf of 1 1 9, 1 20, 1 25 116-17, 147 "blow-out" areas 18, 237-8 Caspian Sea 61, 62-3 Cockburn Sound, Western Australia boating 18 Caulerpa 232, 235 111, 112, 113 Brazil 247 eastern Mediterranean 68, 69, 71 cockles 135,246 East Africa 86-7 Malaysia 155. 156 cod, Atlantic 209 mid-Atlantic region 219 western Mediterranean 52-3. 54, Colombia239, 241,257, 257 NortfiAmerica204, 212, 213 55 Comoros 95, 257 western Europe 42, 43 Caulerpa cactoides 126 Connecticut, US 209, 212 see a/so shipping Caulerpa prolifera 66, 68, 71, 155 Coorong Lakes, Australia 130

Bonaire 14. 238 Caulerpa racemosa 55, 68, 69, 71, coot, red-gartered 245 Boston Harbor 208 155 coral reefs 2 Botany Bay 123 Caulerpa scalpelliformis 68 East Africa 82, 84 bottlenose dolphin 248 Caulerpa serrulata 70 Eastern Australia 120-1 Boundary Bay, Canada 201-2 Caulerpa taxifolia 55 "halo zone" 71

Branta bernicla (brant goose) 40, 210 causeway development Malaysia 1, 153, 155. 157-8

Branta bernicla nigricans Iblack Bahrain 6, 76 Red Sea 69-70 brant] 200 Kosrae 164-5 166, 167 South America 245, 246 Brazil Cayman Islands 251. 256 Thailand 145-6 Abrolhos Bank 243, 247 Ceramium 60, 61, 62 western Pacific 161-3 biogeography 245-6 Cerithium tenetlum 175 corals 245, 246 ecosystem description 243-4 Chaetomorpha linum 219, 221 Core Sound, North Carolina 218 Itamaraca Island 243, 244 Champia sp. 197 Corpus Christi Bay, Texas 227, 229 Patos Estuanne Lagoon 244, 248 Chandeleur Islands, Louisiana 226, Corsica 57, 53, 55 policy and protection 248-9, 256 227 Costa Rica 238, 257, 257

seagrass losses and coverage 14. Chara 62 crabs 40, 83, 156, 196-7 246 Charlotte Harbor, Florida 225 blue 216. 245-6, 248 seagrass species 251 Charophyceae 63 hermit 101

Brest, Bay of 40 Cheilio enermis 1 77 New Zealand endemic 135 British Columbia 199-204 Chelonia mydas see green turtle Thailand 148 British Indian Ocean Territory 251. Chesapeake Bay, US 216, 218, 220-1 threatened species 72 256 Chicoreus ramosus 98 croaker, whitemouth 248 Brunei 251 chicoric acid 55 Croatia 257, 257 Buenos Aires 246 Chile 10, ?4, 243, 246, 257 crustaceans 40, 97-8, 156 Bulgaria 251 China 185,257 Caribbean 236-7 "bullata" ecophene 66 Chinocoteague Bay 220 Indonesia 175

vvn X^^.

t( ,

290 WORLD ATLAS OF SEAGRASSES

seed consumption 190 seagrass species 257 seagrass productivity and value South America 245-6 uses of seagrasses 30 85-7 see also named groups and depth distribution threats to seagrasses 86-8 species Australia 120-1, 123, 124-5, 130 Eastern Australia 119-31 Cuba224, 238, 2i1, 251.257 Denmark 27, 32,33 biogeography 120-2 Curacao ?4. 238 Japan 186-7 physical characteristics 119 curio goods 85, 98 Malaysia 154 policies and protection 23, 130-1, , Lithuania 30, 33 Red Sea 69, 70 256

Cuyo Island 183 and water quality 27, 32, 33, 112- seagrass coverage 14, 125-8 Cygnus atratus 141 13, 154 seagrass losses 122-5, 126-7 Cygnus cygnus 189 western Pacific 162 threats to seagrasses 129-30 Cygnus melancoryphus 245 Zostera manna 27, 32, 33, 232 uses of seagrasses 122, 128-9 Cymodocea angustata 251-5, 271 Derawan Islands, Indonesia 778 echinoderms97-8, 176 Cymodocea nodosa detritus see also named groups and by country/territory 257-5 direct uses 55, 197 species eastern Mediterranean 65-8 ecological value 40 Echinometra mathaei 86 range map 271 see also beach cast Echinothnx diadema 86 western Mediterranean 48, 49, 50, Diadema antillarum 236 ecological value 75 16-17,24, 129 52-3, 54 Diadema savignyi 86 carbon sequestration 17 Cymodocea rotundata Diadema setosum 86, 98 coastal protection/sediment

by country/territory 251-5 Diani-Chale Lagoon, Kenya 86 stabilization 17, 86-7, 88-9, 116-17. Eastern Australia 128 diatoms 101 147 India 104, 105, 106-7 Dick, Chief Adam 202 nutrient cycling 40, 84, 85 Indonesia 171, 172, 173-4, 178-9 die-back see wasting disease economic value 17-18

Japan 187 Diogenes 1 75 ecosystems Malaysia 156, 157 direct habitat maps 7 adjacent to seagrasses 84

Mozambique 95, 96, 99 distribution maps seagrass 7, 10-13 photosynthetic studies 85 calculating global areas 13-16 see also associated biota range map 272 development 3, 7-8 ecotypes 66, 194-5 Red Sea 69-70, 71 geographic regions 9-10 eel 33 Thailand 144, 146, 147, 148 limitations 13 eelgrass see Zostera marina western Pacific 168, 169 seagrass habitat 7, 13 Egretta garzetta 158 Cymodocea serrulata seagrass species 8-10, 262, 263-86 Egypt 65, 66-7, 67, 252 by country/territory 251-5 dolphin, bottlenose 248 El Dab'a66 India 104, 105 Dominica 257 El Nino Southern Oscillation lENSOl Indonesia 171, 172, 173-4, 178-9 Dominican Republic 241, 257, 257 205, 226 Japan 187 Donuzlav Salt Lake 60 ElSuweisl5uezl67, 68-9, 70-1 Malaysia 153, 755 dragging, net 213 Elat, Gulf of 67, 68-9, 70-1, 74 Mozambique 95, 96. 99 dredging Elpidium 1 75 range map 272 Arabian Gulf 76, 78, 80 emperor fish Red Sea 68-9 for bivalves 43-4, 219, 220-7 pink ear 95 Thailand 144, 145, 146, 147 Malaysia 157 variegated 96 western Pacific 163 mid-Atlantic US 219 endangered species

Cymodoceaceae 6 duck, redhead 228 associated biota 17, 40, 183 Cypraea tigris 85 dugong IDugong dugon) 2, 183 seagrasses 12-13, 188, 236-7 Cyprus 67, 68, 71, 251, 257 Arabian Gulf 78, 79 endemic species 12, 770, 777 740 captivity 180 Enhalus acoroides 13 East Africa 83, 88 by country/territory 257-5 Eastern Australia 119 India 103, 704 D feeding 147, 149 Indonesia 171-80, 181 Dahlak Archipelago 69 India 102, 105 Japan 187 Dares Salaam 87 Indonesia 180 Malaysia 154, 156 Dasycladales 235 Japan 189 Mozambique 95, 96, 99 David and Lucile Packard Foundation Malaysia 154, 156 Philippines 183 168 Thailand 145, 747 148-9 range map 263 Deception Bay, Queensland 123 western Pacific 164 Red Sea 68, 70 decline, global 20 seeds 149, 166-7 deepwater seagrasses 69, 70, 1 20-1 Thailand 144, 145, 146. 147 123, 124-5, 130 transplantation 176 5-7 definitions uses 87, 122, 154, 166-7 deforestation 138-9 earthquakes 238 western Pacific 162, 166-7, 168-9 216-22, 220-1 Delaware East Africa 82-90 ENSO lEl Nino Southern OscillationI Denmark biogeography 82-5 205, 226 policies and protection 34-5 policies and protection 88-90, 258, Enteromorpha 60, 61, 62, 87 seagrass distribution and losses 260 environmental impact assessment 6, 27-8, 31-2,33 seagrass coverage 87-8 76, 77 1 1

Index 291

epibenthos 124-5 Caspian Sea 63 Glenan Archipelago 45 epifauna 27, 28, 101, 190 East Africa 83, 85-6, 88 global habitat distribution 13 Epinephetus malabancus K7 Eastern Australia 128-9 global seagrass area 13-16 epiphytic algae 10-1 Korea 196-7 Global Seagrass Workshop 2, 287 Black Sea 60 Malaysia 154, 156. 158 global warming see climate change Caribbean 235, 236-7 mid-Atlantic region 216 goatfish, dash-dot 97 India 101 Mozambique 95-8 goby, tailspot 96 Korea 197 New Zealand 135 Gracilaria coronopifolia 155, 156

Malaysia 156 north western Atlantic 209-10 Grand Cayman 14. 238 Western Australia 113 shrimps 77-8, 128-9,23/ grazing western Europe 40 South America 245-6 birds 28, 40, 141, 189, 199,200, Eritrea 69, 252 Thailand 147-9 210,245 Esox lucius 33 value of seagrasses 17 dugong 147 Estonia 29, 34, 252 western Europe 40 fish 83, 85-6, 183 Eucheuma 237 western Pacific 163-4 sea turtles 247 Eucheuma spinosa 87-8 fishing methods sea urchins 86, 236. 241 Euro-Asian seas invertebrates 97-8, 99, 212, 213. snails 28, 44 seagrass coverage 14 219,220-; Great Barrier Reef 120-1, 126-7

see also Aral Sea ; Azov Sea ; Black mechanized 148-9 deepwater seagrasses 124-5 Sea; Caspian Sea seine net 85-6 Green Island seagrass meadows Europe, western traps 96-7 128-9 historical perspectives and losses Western Australia 115 Marine Park 23, 131 40-3 FloresSea 173-4 Great Bay, New Hampshire 207, 208. policies and protection 44-5 Florida 11 210

seagrass coverage 14. 43 east coast 14. 236-7 Greece 66, 67, 68, 252 threats to seagrasses 43-4 Gulf of Mexico 224-5 Green Island seagrass meadows uses and value of seagrasses 38 flounder, winter 209 128-9 see also Mediterranean Sea; flowering 187-8, 201 green turtle 102 Scandinavia flowers Arabian Gulf 79

European Union (EUl female 9, 240 Caribbean 238 Habitats Directive 35, 44, 46, 52 male 189, 237 East Africa 83, 88-9

Water Framework Directive 35 foraminifera 175 Eastern Australia 1 19 eutrophication 3 forestry 138-9 Pacific 164 Black Sea 60 France South America 245, 247 Caribbean 239 Atlantic coast 39, 40, 43, 44, 45 Greenland 252 Denmark 32, 33. 34, 35 Caribbean islands 252 Grenada 52 East Africa 87 Mediterranean coast 51, 55, 56 groundwater 85, 21

Gulf of Mexico 232 protected areas 257 groupers 12. 176 Mediterranean 55 seagrass species 252 Malabar 147

Western Australia 112-13 fruiting 121, 149, 187-8 Guadeloupe 14. 238, 252. 257 western Europe 42, 44 Fucila armillata 245 Guam 162,257 evolutionary origin 10 Funakoshi Bay, Honshu 190 Guatemala 252. 257 fungi 101 Guinea 252 Gulf of Arabia see Arabian Gulf Gulf of Carpentaria 119, 120, 125 Gulfof Kutch 105 Farewell Spit, New Zealand 141 Gulfof Mannar 102, 104, 105

Faure Sill, Western Australia 116-17 Gadus morhua 209 Gulf of Mexico 14, 224-32 ferry terminals 204, 205 gams, seagrasses 128-9 Gulf of Thailand 144-50

Fiji 162, 166, 167, 169.252 Galeta Point, Panama 235 Gulf War oil spill 75-7 filamentous algae 33, 60, 61 Galveston Bay, Texas 227, 230 Guyana 241 Finland 29, 30, 35, 252 gastropods 28, 44, 83, 85, 155, 156. First Nations people 199 175-6,236,237 fishfarming 154, 158. 213 Gazi Bay, Kenya 82, 84. 85, 86 fish habitat areas (FHAsl 131 genetic testing 262 H fish species Geographe Bay, Western Australia Haad Chao Mai National Park,

associated with seagrasses 11. 12 109-10, 111, 112 Thailand 144-5, 146. 147, 149 Caribbean 235-6, 237 geographical information systems habitat distribution, global 13

Indonesia 176-7, 180 [GiSI7, 166 habitat maps 7, 13 Korea 196 geographical regions 9-10 Habitats Directive (EUl 44, 46 Mozambique 95-6 Germany 28, 29, 30, 33, 252. 257 Haiti 241, 252 threatened 12 Cerres oyena 83, 96 Hatimeda 235, 239 see also named fishes Gerupuk Bay, Indonesia 173, 175, Halodule spp. fisheries 177, 178 leaf morphology 82-3 Arabian Gulf 77-8 Gilimanuk Bay, Indonesia 178 taxonomy 243-4, 262, 272 Brazil 245-6 Gippsland Lakes, Australia 123 Halodule beaudettei 251-5. 262, 273 292 WORLD ATLAS OF SEAGRASSES

Halodule bermudensis 251-5. 262, South America 243, 245 Hervey Bay, Queensland 121, 122, 273 southernmost limit 243 123, 725 Halodule emarginata 2^3-4, 257-5, Thailand 144, 145, 74,^, 148 Heterozostera tasmanica see 273 Halophila engelmanni Zostera tasmanica Halodule pinifoUa by country/territory 251-5 Hippocampus 40. 51 by country/territory 251-5 Caribbean 234-5 Holothuna atra 148, 164 India 704 Gulf of Mexico 224, 225-6, 227-31 HolothunascabraSZ. 96-7. 148, 176 178-9 Indonesia 171, 772, range map 265 Holothuroidea 85, 96-7. 98, 148, 154, Malaysia 153, 155-7 Halophila hawaiiana 251-5. 266 163-4, 176 range map 274 Halophila johnsonii 236-7. 251-5. Homarus amencanus 209 Thailand Ui, U6. 747 266 Honduras 252. 257 Halodule uninervis Halophila minor 262 hotspots, biodiversity 9, 10, 185 Arabian region 74, 75-8, 80 by country/territory 251-5 Hudson Bay 207, 212 by country/territory 257-5 Indonesia 77S-9 human food 87, 122, 136, 148, 166-7, Eastern Australia 72S Mozambique 99 199,204 genetic studies 262 range map 266 Hurricane Carta 227 India 704, 105 Thailand 144, 146 Hurricane Gilbert 238 Indonesia 171, 172, 173, 77S-? Halophila ovalis 2 Hurricane Hugo 237-8 Malaysia 154-5, 156, 157 Arabian region 74, 75, 77, 78 Hurricane Roxanne 237 Mozambique 95, 96. 99 by country/territory 257-5 hurricanes 218, 219, 227, 257, 237-8 range map 274 dugong grazing 747 hydraulic dredges 219, 220-7 Red Sea 69-71 Eastern Australia 122, 725, 72S Hydrobia 28, 44 shoot density 173 India 704 Hydrochaeris hydrochaeris 245 Thailand U4, 74<5, 747 Indonesia 171, 772-3, 778-? Hydrocharitaceae 6 western Pacific 166 Japan 186 Hydropuntia 237 Halodule wrightii Malaysia 153, 154-6 hydrothermal vents 72 Brazil 246 Mozambique 95, 96. 99 by country/territory 257-5 photosynthetic studies 85 Caribbean 234, 235, 236. 237, 239. range maps 267 240 Red Sea 69, 70, 71 East Africa 82-3, 87 salinity tolerance 74 Iceland 27, 252 Gulfof Mexico 225, 227, 22S-?, taxonomy 262 India 230,231-2 Thailand 144, 145, 747, 148 associated biota 101-2, 105 India 704 var ramamurtiana 104 biogeography 102-3 male flower 237 western Pacific 162-3, 167 Kadmat Island 70^-7 mid-Atlantic 216-17 region Halophila ovata policies and protection 105, 108, Mozambique 95, 96. 99 by country/territory 257-5 257 northeast Pacific 200, 203 India 704 seagrass coverage 74, 702 northernmost limit 216-17 range map 267 seagrass species 252 range map 274 Red Sea 69 threats to seagrasses 104-5 salinity tolerance 228-9. 231-2 Halophila spinulosa Indian River, Florida 236 South America 243, 244, 245, 247 Australia 724-5 Indonesia 257 taxonomy 82-3, 262 by country/territory 257-5 associated biota 174-7, 179-80 Halophila spp. 121, 235,263 Indonesia 171, 777-S historical perspective 180 Halophila australis 251-5. 264 Philippines 183 policy and protection 180-1, 257 Halophila baillonii range map 268 seagrass coverage 74, 178-9, 180 Brazil 243, 244 Halophila stipulacea seagrass species and ecology by country/territory 257-5 Arabian region 74-6, 78 171-4,252 Caribbean 234-5 by country/territory 257-5 Inhaca Island, Mozambique 96-7. 99. range map 264 East Africa 87 100 Halophila beccarii 171 eastern Mediterranean 65-6, 68 integrated coastal zone management by country/territory 257-5 India 704 89-90 India 102, 103-4 Mozambique 95, 99 international agreements 35 Malaysia 156-7 153, range map 268 introduced species see alien species range map 264 Red Sea 68-72 invertebrates Thailand 144, 146 salinity tolerance 74 India 707 Halophila caphcorni9, 251-5. 265 western Mediterranean 48, 49-50, New Zealand 134-5, 740 Halophila decipiens 52-3 southeastern Africa 97-8, 99 by country/territory 257-5 Halophila tricostata see also named species and Caribbean 234, 235 by country/territory 257-5 groups Eastern Australia 725 Eastern Australia 121, 124, 725 Ionian Sea 66, 67 Gulf of Mexico 224, 230, 231, 232 range map 268 Iran 74, 75 India 704, 105 Hawaiian Islands 166 Iraq 75 Indonesia 171, 778-? heavy metal pollution 33, 87 Ireland 38-9, 252 Malaysia 153, 154, 755 Helsinki Convention [HELCOMl 35 Northern 43 range map 265 herring. Pacific 199 Israel 67-8. 70. 252. 257 1

Index 293

Italy 50. 51. 52.252.257 Kutch, Gulfof 105 Louisiana, US 226, 227 Itamaraca Island. Brazil 243, 2^4 Kuwait 74, 75 253 Lutjanus fuivifiamma 97 Iwate Prefecture. Japan 190 Kuwait Action Plan 80 Izembek Lagoon, Alaska 199, 200 Kwakwaka'wakw Nation 202 Kwangyang Bay. Korea 197 Kwazulu-Natal, South Africa 94 M Kylinia 60 macroalgae alien species 55, 68, 69, 71, 155 Jamaica 238, 241,252, 257-S Baltic Sea 34 Japan 185-6 Caribbean 235, 236-7 biogeography 186-8 culture 87-8, 176. 197 historical losses 188 Labynnthula zosterae 18. 38. 138. East Africa 84. 87 losses of seagrasses 189 207 Eastern Australia 126-7 seagrass coverage H. 188 Laguna de Alvarado, Mexico 230, 231 Euro-Asian enclosed seas 60, 63 seagrass species 252 Laguna de Tamiahua. Mexico 230. 231 Gulf of Mexico 232 tfireats to seagrasses 188-9 Laguna de Terminos. Mexico 230. 231 India 102 uses of seagrasses 188 Laguna Madre. Texas 227. 228-9 Indonesia 174

Jervis Bay, New South Wales 1 Laguna Ojo de Liebre, Baja Japan 188 Jordan 69, 252 California 199 Malaysia 155-6 Jubail Marine Wildlife Sanctuary, Lakshadweep Islands 102, 104, 106- Mediterranean 52, 53, 55 Saudi Arabia 78 7 mid-Atlantic region 219, 221 Lampung Bay, Indonesia 178 Mozambique 93 Lamu Archipelago, Kenya 83, 87 Scandinavia 33, 34 land reclamation Western Australia 113 K Arabian Gulf 76, 78, 80 western Europe 40, 44 Kadmat Island, India 106-7 East Africa 88 Macrophthalamus hirtipes 135 Kaduk Island, Korea 197 Japan 189 Madagascar 94, 100,255,258 Karimata Island, Indonesia 178 Korea 198 maerl bed 46 Karkmitsky Gulf 60 Malaysia 155-7 Magellan Straits 244 Kattegat Strait, Denmark 34, 35 Philippines 183-4 Maia squinado 40 Kazakhstan 252 see also coastal development Maine, US 207-10, 2?2, 273 Kenya latitude 13, 209 179 biogeography 82-3, 85 Latvia 29, 34, 253 Malaka Strait 179 Gazi Bay 82, 8i. 85, 86 Laurencia 62, 235. 236-7 Malaysia policies and protection 88-90, 258 Law of the Sea Treaty 167 biogeography 153-4 seagrass coverage 87-8 Lebanon 67, 68. 253 ecosystem description 152-3 seagrass productivity and value Lelu Island. Micronesia 164-5 historical perspectives 152, 154 85-7 Lepidochelys olevacea 102 macroalgae community 155-6 seagrass species 253 Lepilaena 6 policies and protection 152, 158-9, threats to seagrasses 86-8 Leptoscarus vaigiensis 95. 97 258 Kepulauan Serlbu reefs 175 Lethnnus lentjan 95 seagrass species 253 Kerch Strait 60 Lethnnus variegatus 96 seagrass losses and present

Kiel Bight 28 Libyan Arab Jamahiriya 253 coverage 14, 154-7 Kimberley coast. Western Australia light availability Tanjung Adang Laut shoal 154, 155 110 Australia 111-13 threats to seagrasses 157-8 Kiribati 253 Scandinavia 27. 32, 33 253 Ko Samui, Thailand 145-6 western Europe 44 Maluku Island, central 179 KoTalibong, Thailand 145, U6. 149 see a/so eutrophication; sediment manatee 12 236. 238, 245 Korea, Republic of 185 loading Manatee County, Florida 225

biogeography 193-7 light requirements 1 1 1-12. 235 manatee grass see Syringodium historical losses 197 Limassol, Bay of 65 filiforme policy and protection 198, 258 Limnona simulata 236 mangroves 82, 84. 85, 110, 245 seagrass distribution and coverage Limon earthquake 238 Manila Bay 183 U. 193, 197 limpet Mannar, Gulf of 102, 104. 105 seagrass research 196 eelgrass 140 210 Maori people 135-6 seagrass species 253 New Zealand 140 maps threats to seagrasses 198 Lithuania 29. 30. 33. 253 calculating global areas 13-16

uses of seagrasses 197 Little Egg Harbor. New Jersey 210 data sources and methods 3, 7-8 Kos68 lobster 209 deepwater seagrasses 124-5 Kosrae, Micronesia H, 164-5, 166, spiny 203. 237 limitations 13

168. 169 Lombok. Indonesia 171, 172. 173. seagrass habitat 7, 13

Kotania Bay, Indonesia 175, 176, 174-6. 177. 180 species ranges 3, 262, 263-86 178-9 Lomentana hakodatensis 197 Maputo Bay, Mozambique 96-7, 99 Krasnovodsky Bay 62-3 Long Island, US 209, 212 Maquoit Bay, Maine 210, 213 Kung Krabane Bay, Thailand 145, 146 losses, global 20 marema fish traps 96-7 Kuta Bay, Indonesia 177 178. 180 Lottiaalveus 140. 210 mariculture seeaquaculture 1

294 WORLD ATLAS OF SEAGRASSES

marine protected areas western Pacific 163 historical changes in distribution Australia 115-17. 131, 256 see also named species and 135-8, 139, 141 East Africa 88, 258, 260 groups policies and protection 139-41 global ?9, 20, 23, 256-61 Mombasa Marine Park. Kenya 88-9 seagrass species and distribution Malaysia 152. 158-9,258 Monaco 258 134, 735, 136-7. 253 New Zealand 141 monitoring, global 168-9, 184 threats to seagrasses 138-9 western Pacific 167 Monroe County, Florida 224-5 use of seagrasses 136-7 Marsa t«1atrufi Harbor, Egypt 66 Montepuez Bay, Mozambique 23, 95, New Zealand Fisheries Act (19961 Marseille-CortiQU region, France 51 96, 97, 98 140-1 Marshalllslands 166,253 Moreton Bay, Queensland 119, 123 Newfoundland 207 Martinique U. 236, 238, 252. 253. 258 Morocco 253 Nicaragua 237, 238, 253. 259 Mar/land, US 218, 221 Morone saxatilis 209 Nicobar Islands 101. 102-3. 704, 105

Massachusetts, US 207-8, 210, 212 morphological characteristics 5 Ninigret Pond, Rhode Island 210, 27 7 Mauritania 253. 258 Halodule spp. 82-3 nomenclature 5-7 Mauritius W, 95, 99, 100, 253. 258 Halophita stipulacea 66 non-governmental organizations 150, Mayotte 253 and nutrients 82-3 167. 170 Meandrina brasiliensis 245 Phyllospadix spp. 195 North America Mecklenburger Bight 28 Zos(era spp. 190. 194-5 mid-Atlantic coast 216-22 Medes Islands, Spam 54 moshiogusa 188 Pacific coast 199-204 Mediterranean Sea, eastern 65-8, 71- Mozambique 23, 94 North Atlantic, western 9 2 biogeography 93 biogeography 209-10 Mediterranean Sea, western 9, 48-56 fisheries 95-8 ecosystem description 207-9 associated species 51 protected areas 258 historical perspectives 210

productivity and biomass 52-3. 55 seagrass losses and coverage 14. policy and protection 213-14 seagrass coverage M, 51-2 98-100 seagrass coverage 212 species distribution 48-51, 52-3 seagrass species 253 seagrass losses 210-1 threats to seagrasses 55-6 threats to seagrasses 97 threats 212-13 meiofauna MPAs see marine protected areas North Carolina, US 216, 216-17, 218- India 107 mttmbi 86 20. 222

Indonesia 174-5 mullet 248 northeast Pacific 9. 199-205 Mexico Mullus surmuletus 40 biogeography 200-4 Caribbean coast 238. 240 murex 98 historical perspectives 203-4 estimated coverage 14 Muscutista senhousia 205 policy and protection 205 Gulf of Mexico coast 230-2 mussels 205 seagrass coverage 204 Pacific coast 199, 201 blue2B. 34. 209-10. 2/3 threats to seagrasses 204-5 protected areas 258 culture 43. 213 Northern Ireland 43 seagrass species 253 harvesting 210, 212, 213 Northumberland Strait. Canada 207, Mexico. Gulf of /4, 224-32 Mya arenaria 213 212 Micronesia 161 Myanmar 253 Norway 27, 30-1,253 biogeography 162 Mytitus edulis 28. 34. 209-10. 273 Notoacmea helmsi Iscaphal 140 historical perspectives 164-6 Nova Scotia 207, 212 Kosrae Island 14, 164-5 166, 168. nutrient cycling 17, 84. 85

169 nutrient loading 1 policy and protection 167, 170 N Gulf of Mexico 232 seagrass species 253 names, local, for seagrasses 135-6, Indonesia 171-2 SeagrassNet 168-9 188 and leaf morphology 82-3 uses and threats to seagrasses Nantuna Island, Indonesia 178 mid-Atlantic coast 219, 220 166-7 Narragansett Bay, Rhode Island 208, New Zealand 139-40

mid-Atlantic region 210 northeastern US 27 7 biogeography 216-17 natural 18, 218. 219. 227. Red Sea 71-2 historical perspectives 217-18 237,237-8,238 Tampa Bay 226 policy and protection 219-22 net dragging 213 Western Australia 112-13 seagrass distribution 218-19 Netherlands 39, 4 1. 43, 44, 253 western North Atlantic 27 7, 212 threats to seagrasses 219, 220-1 253. 259 see also eutrophication; sewage Miliolina 175 New Caledonia 252 pollution mining 55, 149, 155-7. 239. 241 New England. US 210, 212 Nyali-Shanzu-Bambun Lagoon, Mississippi 225-7 New Hampshire. US 207-8. 208. 210, Kenya 86, 88-9 mojarra. blacktip 96 272, 214 mollusk shell middens 165 New Ireland. Papua New Guinea 169 mollusks New Jersey. US 207. 209. 272 digging/dragging for 98, 99, 157, New South Wales 121. 127 158. 210,212,2/3 New York State. US 11. 209, 272 ocean currents 191 dredging for 219, 220-1 New Zealand Odontodactytus scyltarus 175

East Africa 83, 85 ecosystem description 134-5 oil pollution Indonesia 175-6 endemic species 140 Arabian Gulf 75-7, 78, 80 New Zealand 135, 140 estimated coverage 14 Caribbean 239-40

7/ Index 295

East Africa 87 Phyllospadix serrulatus productivity 15, 16-17

Europe kU,, 50 by country/territory 251-5 East Africa 85 Malaysia 155 northeast Pacific 202, 203 Indonesian seagrasses 171-4 northeast Pacific 205 range map 285 measurement 180 Okinawa Island. Japan 189 Phyllospadix torreyi Mediterranean 52-3, 55 Onnan 75, 253 by country/territory 251-5 and nutrient availability 171-2 Oresund region 28, 31, 34 northeast Pacific 199, 202, 203 Thalassodendron cibatum 84, 85 Osmerus mordax 209 range map 286 western Europe 40 Otsuchi Bay, Honshu 190 uses 199,205 Zos(era 196 overwater structures 34, 204, 205 phytoplankton 44, 102, 113 protection of seagrasses 20, 23 oysters 97 Picnic Cove, Shaw Island 203 Protoreaster nodosus 1 76 culture 43, 154, 197,205 pike 33 Pseudopleuronectes americanus 209

dredging 220-1 Pitbara coast. Western Australia 1 10 Pseudosquilta citiata 1 75 Pinctada nigra 97 Pteragogus ftagellifera 97

Pinna muricata 3, 97 Puerto Galera, Philippines 184 Pinna nobilis 51 Puerto Morelos Reef National Park

pinna shell 3, 51, 97 240 Pacific flyway 200 Pleuroploca trapezium 98 Puerto Rico 238, 239, 254. 259 Pacific Ocean see northeast Pacific; Pohnpei, Micronesia 168 Puget Sound 204, 205 western Pacific islands Poland 33, 254 push seines 148-9

Pagrus auratus 135 pollution Pyrene versicolor 1 75 Pagurus spp. 175 Caribbean 239, 241 Palau 162, 164, 166, 167, 169, 253, heavy metals 33, 87 259 Mediterranean 71-2 Pamlico Sound, North Carolina 218 Red Sea 71-2 Q Panama 235, 236, 241, ,?53, 259 sewages/, 128-9. 161 Qatar 74, 75. 254 Panulirus argus 237, 246 South America 247 queen conch 236, 237 Panuiirus interruptus 203 thermal 72 Queensland, Australia 119, 122, 123, Papua New Guinea 161, 165, 166 toxic chemicals 113-14 125

biogeography 162 Western Australia 1 12, 1 13-14, 1 15 seagrass protection 130-1 policies and protection 167, 259 see also eutrophication; nutrient Queensland Fisheries Act 130-1 seagrass monitoring 169 loading: oil pollution Quinmba Islands, Mozambique 95, seagrass species 254 polychaetes 43, 107, 114 98, 99. 100 Pan Island, Indonesia 176-7 Polysiphonia 60, 61, 62 Parque Nacional Arrecifes Puerto Polysiphonia japonica 197 l^lorelos 240 Port Phillip Bay, Australia 123 Parque Natural Tayrona, Colombia Portsmouth Harbor, Maine 207, 208. R 239 214 rabbitfish97, 183 parrotfish 83, 85, 86, 95, 96-7 Portugal 39, 43, 254 Ramsar Convention 141 Parupeneus barberinus 97 Portunus pelagicus 83, 148, 156 rapid assessment technique 77 Patos Estuarine Lagoon, Brazil 244, Posidonia angustifolia 251-5. 277 ray 232

248 Posidonia australis 1 14 razorclam, stout 248 Pecten novazelandiae 135 by country/territory 251-5 Red Data Book species 188 Pengkalan Nangka, Malaysia 158 Eastern Australia 122 Red Sea 67 Perth City, Australia 112, 115 range map 277 pollution 71-2

Philippines 14, 183-4,254,259 Western Australia 113. 117 seagrass distribution 66, 68-71, 77 phosphorus levels 172, 221 Posidonia coriacea 251-5. 262, 278 Redonda Island, Brazil 27 photosynthetic studies 85 Posidonia denhartogii 251-5, 262. reefs, artificial 197 Phyllospadix spp. 203, 284 278 remote sensing 8, 86 Phyllospadix iwatensis Posidonia kirkmanii 251-5. 262, 278 reproduction 162, 187-8 by country/territory 251-5 Posidonia oceanica research Japan 186 by country/territory 251-5 Korea 196 Korea 193, 194, 197-8 eastern Mediterranean 65-7, 68 Mediterranean 48 morphological features 195 range map 279 photosynthesis 85 range map 284 seaweed competition 55 South America 244 Phyltospadix japonicus uses 55 Resource Management Act 119911, by country/territory 251-5 western Mediterranean 48, 49. 50. New Zealand 140 Japan 186 52-4. 55-6 restoration of seagrasses 23 Korea 193, 194, 197. 198 Posidonia ostenfeldii 251-5, 262, 279 north western Atlantic 208. 209 morphological features 195 Posidonia robertsoniae 251-5. 262 Wadden Sea 41 range map 285 Posidonia sinuosa 113. 123, 251-5, restricted range species 12-13 Phyllospadix scouleri 279 Reunion 259 by country/territory 251-5 Posidoniaceae 6 Rhode Island, US 208-9, 210, 211. 212

northeast Pacific 199,202-3 Potamogeton 6, 29 Rhodes IRodosI 65 range map 285 Potamogeton pectinatus 61, 63 Rias Coast, Honshu 190 uses 199 Princess Charlotte Bay 121 rimurahia 136 4

296 WORLD ATLAS OF SEAGRASSES

Rio de Janeiro 2i6 Sarasota Bay, Florida 225 seine net fishing 95-6, 98, 148-9 roach 33 Sarawak 153 Senegal 254 Rodos IRhodesI 65 Sardinia 52, 55 Sen Indians 199 Romania 25A Sargassum spp. 155 Sermata Islands, Indonesia 179 Rotaliina 175 Sargassum muticum 44 Serranidae 147-8 Rufiji Delta, Tanzania 87 Saudi Arabia sewage pollution Ruppia cirrhosa Arabian Gulf 74-80 Green Island, Australia 128-9 Caspian Sea 62 protected areas 259 western Mediterranean 51 eastern Mediterranean 67 Red Sea coast 67, 69-70 western Pacific islands 161 western Europe 38, 39 seagrass species 254 Seychelles 94, 95, 99-100, 254. 259 Ruppia maritima Saudi Arabia-Bahrain causeway 76 Shark Bay, Western Australia 109-10, Caribbean 23i, 235, 236 scallop 115, 116-17 Gulfof Mexico 225-6, 227, 230, bay 209-10, 216 Shaw Island, Washington 203 231,232 New Zealand 135 shellfish India 104 scallops, Chilean 246 Brazil 246 Indonesia 171, 180 Scandinavia culture 43, 154, 197,205,213

Korea 193, 194. 197. 198 historical and present coverage 14. harvestings, 97-8, 99, 210, 212, Malaysia 15A 30-4 2/3,219,220-; mid-Atlantic region 216-17 policy and protection 34-5 Mozambique 97-8 Mozambique 99 seagrass species distribution 27- western Europe 40, 43-4 northeast Pacific 199, 200. 203 30 western North Atlantic 209-10, South America 245, 246, 247-8 threats to seagrasses 34 212,213 Thailand U4, 146 uses of seagrasses 30 see also named groups and var. longpipes 203 Scotland 38, 43 species of shellfish var maritima 203 sea cucumbers 85, 96-7. 98, 148, shipping 44, 130,204,205 western Europe 38 154. 163-4, 176 see also boating; oil pollution western North Atlantic 207, 208, sea goose (black brantl 200 shoal grass see Hatodule wrightii 209 sea horses 12. 13, 40, 51 shoot density 173, 231-2 Ruppiaceae, taxonomy 6-7 sea rabbit 40 shoot height 194-5 Russian Federation 62, 254. 259 sea snake, banded 166 shrimp fisheries 77-8, 128-9, 231. Rutilus rutilus 33 sea stars 51, 176 246 Ryukyu Islands, Japan 185, 186, 187, sea turtles Sicily 52 188, 189 Arabian Gulf 79 Siderastrea stellata 245, 246 Caribbean 238 Sierra Leone 254 East Africa 83, 88-9 Siganus canaliculatus 183

Eastern Australia 1 19 Siganus sutor 95, 96 endangered species 183 Sinai 71 Sabah, Malaysia 153, 154, 157-8 grazing 247 Singapore 254. 259

Sabella spatlanzani 1 1 India 102 Skagerrak Strait, Denmark 34, 35 SACs (special areas of conservation] Pacific 164 slime molds 18,38, 138,207 46 South America 245, 247 Slovenia 259 sailing see boating sea urchins 40, 51, 96-7. 98, 176 Smaragdia viridens 236 St Kitts and Nevis 254 grazing and competition 86, 236. smelt 209 St Lawrence River 212 241 snails St Lucia 239, 254. 259 sea-level rise 167,219, 241 mud 44 St Vincent and the Grenadines 254. Seagrass-Watch 168. 184 small green 236 259 SeagrassNet 168-9. 184 snake, banded sea 166 Saleh Bay, Indonesia 179 seaweeds snapper salinity alienspecies55, 68, 69, 71, 155 blackspot 97 Arabian Gulf 74 farming 87-8, 176, 197 New Zealand 135 Aral Sea 63 see also macroalgae Solomon Islands 163, 164, 254

Baltic Sea 28 Sebastes inermis 1 96 Somalia 254 Caspian Sea 62 Secchidepth27, 32, 33 South Africa 10 Gulf of Mexico 228-9, 231-2 Seychelles 259 biogeography 93-4

mid-Atlantic region 217 sediment loading 1 present coverage 100 salinity tolerance East Africa 87 protected areas 259 Hatodule wrightii 228-9. 231-2 Eastern Australia 123 seagrass species 254 Hatophila spp. 74 New Zealand 138-9 South America Zostera noltii 62. 63 North America 210-11 biogeography 245-6 Sallsh people 203 Western Australia 113 ecosystem description 243-4, 245 Samoa 162, 254 sediment stabilization 17, 116-17 historical perspectives 246 San Francisco Bay 204 seeds policy and protection 248-9 San Juan Archipelago 203 consumption 190 research data 244 sand mining 155-7, 239 Enhatus acoroides 149, 166-7 seagrass species and distribution Sao Paulo 246 human uses of 148, 166-7 246-8, 254 Sao Tome and Principe 254 production 121, 187-8 South Sea 193

TF 1

Index 297

Spain39, ^3. 51. 53-4.55 seagrass productivity and value Tobago 14. 238 marine protected areas 259 85-7 Tokyo Bay 188 seagrass species 53. 254 seagrass species 255 Tonga 162. 255. 260 special areas of conservation ISACsl threats to seagrasses 86-8 Torres Strait 120. 125-6 kb Tarut Bay. Saudi Arabia 74-5. 75-6. 77 tourism Spermonde Archipelago, Indonesia Tasmania 121. 122. 127-8 Caribbean 238-9 171-2. 174 taxonomy 5-7. 262, 263, 269, 270, 271, East Africa 86-7

Sri Lanka 25i 272, 275. 276. 277, 280, 284, 286 toxic chemicals 1 13-14 Stethojulis strigiventer 96 TBT Itributyltinl 114 Western Australia 113-14

stomatopods 175 Te Angiangi Marine Reserve, New Tozeuma spp. 1 75 storms 120. 123. 167.218.219 Zealand 141 transplantation of seagrasses 23, StrombuB gibberulus 85 tectonic activity 205, 238 176, 208 209 Strombus gigas 237 Teluk Kemang, Malaysia /55 transport infrastructure 164-5, 166 Strombus trapezium 85 teripang trade 176 trap fisheries 96-7 Sudan 254 Texas 227-30 trawling 52. 53. ST. 115 Suez. Gulf of 67. 68-9. 70-1 Thailand tributyltin (TBTI 114 Sulawesi. Indonesia 171-2. 174. 178 biogeography and seagrass Trichechus manatus 236. 238, 245 surfgrasses see Phyllospadix spp. species 144-6. 255 Trinidad and Tobago 238, 239, 241, swan dugong 145. 147 148-9 255 260 black U1 estimated coverage 14 Tripneusles gratilla 86, 98, 176 black-necked 245 historical perspectives and losses Trochus niloticus 163, 175 whooper 189 146-8 trochus shell 163, 175 Sweden policy and protection 149-50. 260 Tropical Storm Agnes 218 east coast 28-30. 31 threats to seagrasses 148-9 tropics, stresses to seagrasses policies and protection 35 uses and value of seagrasses 146-8 162-3 seagrass species 254 Thalassia 269 Tudor Mangrove Creek. Kenya 83 west coast 27-8. 31 Thalassia hemprichii 2 tulip shells 98 Syngnathoides biaculeatus 177 biomass and shoot density 173 Tunisia 55. 255, 260 Syria 68, 255 by country/territory 251-5 Turkey 60, 68, 255 Synngodium filiforme Eastern Australia 128 Turkmenistan 255 by country/territory 251-5 India 104. 105. 106-7 Turks and Caicos Islands 255. 260 Caribbean 234, 235, 236. 239. 240. Indonesia 171, 172-4, 177-9 turtle grass see Thalassia 241 Philippines 183 testudinum Gulf of Mexico 224-31, 232 range map 269 turtles see sea turtles range map 275 Red Sea 69-71

Synngodium isoetifotium 2 southeast Africa 93, 94. 95. 96. 99 by country/territory 251-5 Thailand 144. 145. 146 Eastern Australia 128-9 western Pacific 162-3. 168 169 u India 104. 105 Thalassia testudinum Ukraine 255 260 Indonesia 172-4. 178-9 by country/territory 25/-5 Ulva 87. 102 Malaysia 755. 156 Caribbean 234-41 Ungwana Bay, Kenya 88 Mozambique and souttieast Africa female flower 240 United Arab Emirates 74, 75. 11. 78, 95. 96. 99 grazing 236 80, 255 range map 275 Gulf of Mexico 224-32 United Kingdom Red Sea 69-71 range map 269 policy and protection 44, 46, 260 soutfieastern Africa 95. 96. 100 Thalassodendron ciliatum seagrass species and coverage 38, Tfiailand 144. 145. 146. 147 by country/territory 257-5 43, 255 western Pacific 162, 163, 166 East Africa 82. 84 United States Indonesia 171. 172-3. 174. 177-8 Gulf of Mexico 224-30 Mozambique and southeast Africa marine protected areas 260- 93. 94-5, 96. 99 mid-Atlantic coast 74,216-22

Pacific 162, 183 north Atlantic coast 74. 207-14

Tabasco state. Mexico 230 Philippines 183 Pacific coast 74. 199-204 Tagelus plebius 248 productivity 84. 85 seagrass protection 213-14. 219- Taka Bone Rate. Indonesia 174. 178 range map 276 22 Talibong Island. Thailand 145, 146, Red Sea 68-71 seagrass species 255 149 southern Africa 94, 95 United States lUSI Army Corps of Tamaulipas 230 Thalassodendron pachyrhizum 251- Engineers 214. 220 Tampa Bay, Florida 226 5 Tib urchins see sea urchins Tanjung Adang Laut, Malaysia 154, thermal pollution 72 Uruguay 244 155 threatened species uses of seagrasses 16 Tanzania associated biota 17.40. 183 agricultural 61. 62. 188. 197 biogeography 82-3. 85 seagrasses 12-13. 188. 236-7 ancient Egypt 65

policies and protection 88-90. threats to seagrasses 1. 7. 18-20 Australia 122. 128-9 260 see 3(so named threats and under Black Sea 61 seagrass coverage 87-8 named countries and regions East Africa 86

tf 298 WORLD ATLAS OF SEAGRASSES

human consumption 87, 122, 136, western Pacific islands 161, 252 New Zealand 134-7, 141 148, 166-7, 199,204 biogeography 161-4 range 251-5. 281 Japan 188 historical perspectives and taxonomic revision 262 Korea 197 seagrass losses 164-6 Zostera cauiescens Malaysia 154 policy and protection 167, 170 by country/territory 251-5 medicinal 148 present seagrass coverage 166 Japan 187, 189, 790 Mediterranean region 55 seagrass monitoring 168-9 Korea 194, 195, 196, 197 New Zealand 136-7 threats to seagrasses 162-3, 167 morphological features 195 North America 199, 204, 205 uses of seagrasses 166-7 range map 282 Scandinavia 30 Western Samoa 255 Zostera japonica seeds 148, 166-7 Westernport Bay, Australia 122, 123, by country/territory 251-5 Thailand 146-7, 148 126-7 Japan 185-6, 187 United States 217 Whanganui IWesthavenI Inlet, New Korea 194, 195, 196, 797, 198 western North Atlantic 210 Zealand 134, 137. 141 morphological features 195 western Pacific Islands 166-7 widgeon grass see Ruppia maritima northeast Pacific 201, 202, 203-4, see a/so value of seagrasses women 97, 98 205 World Heritage Sites range map 282 Great Barrier Reef 23, 120-1, 124- Viet Nam 184

5. 126-7, 131 Zostera marina V Shark Bay 109-10, 115, 775-77 by country/territory 257-5 value of seagrasses 75, 16-18 World Seagrass Distribution Map 3, ecological value 199 to fisheries see fisheries 7-8, 13, 14-16,21 Euro-Asian seas 59-63 see a(so ecological value; wrasse flowering and fruiting 187-8, 189, economic value: uses of flagfin 97 201 seagrasses three-ribbon 96 Japan 185, 187-8, 189 Vancouver Island 201, 202 Korea 194-5, 196, 197 Vanuatu 162, 164, 166,255 Mediterranean 48-9, 50 52-3 Vauchena dichotoma 63 mid-Atlantic coast 216-22 Venezuela 238, 239-40, 255. 261 morphological variation 194-5 Venice Lagoon 50 Yad Fon Association 150 northeast Pacific 199, 200-1, 204 Veracruz 230 Yamada Bay, Japan 790 northwest Atlantic 207-14 Victoria, Australia 121-2, 123, 127 Yamdena Islands, Indonesia 779 productivity and biomass 40 Viet Nam 14. 183, 184, 255.261 Yap, Micronesia 163, 166 range map 282 Virgin Islands 236, 241, 255. 261 Yellow Sea 193 Scandinavia 27-34 Virginia, US 216, 217-18, 221-2 Yemen 75. 255 southernmost limit 216-17 Yucatan Peninsula 230-2, 240 transplantation 208 uses30, 61,202, 217 variation with latitude 209 38-40, w western Europe 4 7, 43 WaddenSea39, 4?, 43, 44 Zostera mucronata 251-5, 283 Wakatobi Island 77? Zannichellia palustns 33 Zostera muetten 251-5. 283 Wales 43 Zanzibar83, 85, 87-8 Zostera noltii Waquoit Bay, Massachusetts 210 Zeuxo sp. 190 by country/territory 251-5 wasting disease 18 Zostera eastern Mediterranean 65, 66, 68 Black Sea 59-60 flowering and fruiting 187-8 Euro-Asian seas 59-63 mid-Atlantic region 217-18, 219, morphological variation 194-5 protection 44 220 phylogenetic studies 196 range map 283 New Zealand 138, 139 taxonomy 280 salinity tolerance 62, 63 Scandinavia 31, 32 uses 61, 62 Scandinavia 27, 28-9

western Europe 38, 4 7, 42 Zostera angustifoUa 38 western Europe 38-44 western North Atlantic 207, 210, Zostera asiatica western Mediterranean 49, 52-3. 212,213 by country/territory 257-5 54 water quality see eutrophication; Japan 186, 187, 188 Zostera novazelandica 134, 251-5. nutrient loading, pollution; Korea 193, 194, 195, 197-8 262 sediment loading northeast Pacific 200, 203 Zostera tasmanica West Africa 10 range map 280 by country/territory 251-5 779 Zostera caespitosa Chile 243, 246 Western Australia by country/territory 251-5 Eastern Australia 121-2 biogeography 110-11 Japan 186, 187, 188 range map 284 ecosystem description 109-10 Korea 194, 195, 197. 198 Zosteraceae 6 mechanisms of seagrass decline morphology 195 111-14 range map 280 policy and protection 115-16 Zostera capens/s 93-4, 96-7. 98, 99, seagrass coverage 74, 114 100,257-5 281 Shark Bay 116-17 Zostera capricorni threats to seagrasses 114-15 Australia 122

of coastal resources and critical habitats is more

important than ever. The World Atlas ofSeagrasses will

stimulate new research, conservation, and management

efforts, and will help better focus priorities at the

international level for these vitally important coastal

ecosystems.

EDMUND P. GREEN heads the UNEP-WCMC's Marine

and Coastal Programme and is coauthor of World Atlas of

Coral Reefs (California, 2001, with Mark D. Spalding and

Corinna Ravilious).

FREDERICK T. SHORT is Research Professor of

Natural Resources at the University of New Hampshire and coeditor of Global Seagrass Research Methods

(2001).

Front cover: Green turtle (Chelonia mydas) resting in a bed of Thalassodendron dliatum, Watamu Bay, Kenya. Photo: A. Stewart.

Back cover, left: A manatee (Trichechus manatus), feixe-boi in Portuguese, over a Halodule wn'ghtii becJ in Recife, Brazil. Photo: L. Candisani. Center: Halophila spinulosam Papua New Guinea. Photo: M. Richmond. Right: Seastarin Enholus acoroides and Thalassia hemprkhii, Micronesia. Photo: F.T. Short. f v. .V- ^

"Scientists, conservationists, resource managers, and increasingly policy makers are

UNEP WCMC coming to believe that seagrass communities are vitally important ecosystems. This

book will make clear the extent of seagrass assemblages, the magnitude of their

degradation, and the many adverse consequences of failure to conserve and manage

them effectively."

DONALD POTTS

Professor of Biology at the University of California, Santa Cruz

"The World Atlas ofSeagrasses will be an invaluable reference: for the novice it will

provide a broad background in seagrasses and for the spedalist it will give insight

into how local problems of seagrass distribution can be explained on a large scale.'

STEPHEN BORTONE

Director, Marine Laboratory, Sanibel-Captive Conservation Foundation

UNIVERSITY nr rAt Tfn ISBN D-SED-SMDM7-S

Berkeley 94720 www.ucpress.edu

Printed in China 9 178052011240476"