DOCSLIB.ORG

Movement Patterns, Foraging Ecology and Digestive

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Movement Patterns, Foraging Ecology and Digestive MOVEMENT PATTERNS, FORAGING ECOLOGY AND DIGESTIVE PHYSIOLOGY OF BLACKTIP REEF SHARKS, CARCHARHINUS MELANOPTERUS, AT PALMYRA ATOLL: A PREDATOR DOMINATED ECOSYSTEM A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERITY OF HAWAI‘I IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN ZOOLOGY DECEMBER 2008 By Yannis P. Papastamatiou Dissertation Committee: Kim Holland, Chairperson Jeff Drazen Steve Karl Christopher Womersley Tadashi Fukami UMI Number: 3349420 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. ______________________________________________________________ UMI Microform 3349420 Copyright 2009 by ProQuest LLC All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. _______________________________________________________________ ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, MI 48106-1346 We certify that we have read this dissertation and that, in our opinion, it is satisfactory in scope and quality as a dissertation for the degree of Doctor of Philosophy in Zoology. DISSERTATION COMMITTEE Chairperson ii ACKNOWLEDGMENTS I want to particularly thank my chair, Dr Kim Holland for taking me into his lab, and for teaching me some of the tricks of the trade. I would like to thank Dr’s Jeff Drazen, Steve Karl, Christopher Wormersley, and Tadashi Fukami for serving on my committee and always being available for advice when I needed it. I want to thank Dr Carl Meyer for providing me with a large number of opportunities (and employment) while a graduate student. I would also like to thank Dr Joanne Leong and Jane Ball for supporting me for a number of years and giving me the freedom to go to remote locations and do research. I would like to thank my colleagues Christopher Lowe, Alan Friedlander and Jenn Caselle, without whom I would have never completed the work at Palmyra. For helping me in the field in Palmyra I would like to thank T. Clark, N. Whitney, L. Davis, L. Max, M. Sheehy, and G. Goodmanlowe. For all experiments with captive sharks I would like to thank my army of volunteers E. Aus, A. Stankus, T. Tinhan, M. Burns, J. Coloma, E. Grau, C. Clarke, W. Connel, and J. Nakaya. For advice, discussions and arguments I would like to thank my lab mates N. Whitney, T. Clarke, D. Itano, J. Dale, T. Daly Engle, and M. Hutchinson. I would also like to acknowledge J. Dale and A. Taylor for statistical advice. L. Wedding and K. Anthony designed the maps of Palmyra. Finally I would like to thank Alexi and Caroline Papastamatiou, and Lori Davis for putting up with rather a lot from me, but still always being there when I needed it. Most importantly, I would like to dedicate this dissertation in the memory of Dimitri iii Papastamatiou for pushing me to do something I knew I wanted to do, but didn’t realize it at the time. Funding was provided by the National Geographic Society (grant # 7990-06), a UH Sea Grant Project Development fund, PADI Project Aware, and a grant from the Fish Aggregating Devices as Instrumented Observatories of Pelagic Life (FADIO) under DG Research of the European Commission. All experiments were approved by the University of Hawaii Animal Care Committee. iv ABSTRACT Apex predators may have a strong regulatory function in marine ecosystems through both density and behaviorally mediated effects. Understanding the ecological impacts of apex predators is particularly important in predator dominated ecosystems where intra-specific competition may be high. While a number of techniques are available for quantifying predator movement patterns and distribution, little is known of the causative factors that regulate these behaviors. One important aspect of predator behavior is foraging, and an important regulating aspect of foraging is digestion. To advance our understanding of the interrelationship between gastric function and foraging behavior, I tested two types of data loggers for deployment in shark stomachs. One type of tag measured stomach acidity, the other the motility of the stomach wall. Both types of tags were deployed in the stomachs of captive free-swimming blacktip reef sharks to determine the effects of feeding and fasting on gastric digestive function. Gastric pH was maintained low during long periods of fasting, suggesting continuous secretion of acid. Gastric motility was higher for meals of mackerel than for similar sized meals of squid with maximum motility occurring at meal sizes of 1 % body weight. Based on diel patterns of gastric motility and pH, I predict that blacktips will feed daily and preferably forage during times of low water temperature. Palmyra Atoll is a remote, predator dominated ecosystem, and has a large population of blacktip reef sharks. Blacktips at Palmyra are smaller than those at other locations, which may be the result of food-limited growth due to intra-specific competition. Palmyra consists of two lagoons (east and west), and abundance of sharks appears to be similar in both lagoons. Active and passive tracking was used to study the v movement patterns of the sharks at Palmyra. Sharks in the west lagoon utilized small home ranges over scales of days to weeks. Adult sharks selected ledge habitats, while smaller individuals selected sand-flats, and small pups were found in very shallow waters. Fractal analysis revealed that sharks used patches that were 3 – 17 % of the spatial scale of their home range, and that sharks move with a directed walk while in patches but move randomly between patches. Sharks in the west lagoon showed strong site fidelity with some individuals being detected there for over 3 years. Sharks showed little movements between lagoons and sharks in the east lagoon had shorter residence times. Sharks in the west lagoon had higher body condition indices than those in the east lagoon and stable isotope analysis revealed that trophic structure was different between the two lagoons. Conditions differ between the two lagoons which may be driving differences in foraging success. This study reveals the importance habitat can play in the movement patterns, home range and foraging success of sharks and suggests that intra-specific competition could be a strong regulator of apex predator populations in pristine predator dominated ecosystems. Studies of the digestive system revealed that physiology may also regulate some aspects of movement patterns, although field studies will be required to test these hypotheses. vi TABLE OF CONTENTS ACKNOWLEDGEMENTS................................................................................... iii ABSTRACT........................................................................................................... iv TABLE OF CONTENTS...................................................................................... vii LIST OF TABLES................................................................................................. ix LIST OF FIGURES ...............................................................................................10 CHAPTER I: Introduction .....................................................................................12 CHAPTER II: The response of gastric pH and motility to fasting and feeding in free swimming blacktip reef sharks, Carcharhinus melanopterus 21 ABSTRACT...............................................................................................21 INTRODUCTION .....................................................................................22 MATERIALS AND METHODS...............................................................24 RESULTS ..................................................................................................31 DISCUSSION............................................................................................44 CHAPTER III: A new acoustic pH transmitter for studying the feeding habits of free ranging sharks 53 ABSTRACT...............................................................................................53 INTRODUCTION .....................................................................................53 MATERIALS AND METHODS...............................................................55 RESULTS ..................................................................................................59 DISCUSSION............................................................................................59 CHAPTER IV: Scale dependent effects of habitat on movements and path structure of blacktip reef sharks, vii Carcharhinus melanopterus, at Palmyra Atoll: a predator dominated ecosystem 67 ABSTRACT...............................................................................................67 INTRODUCTION .....................................................................................68 MATERIALS AND METHODS...............................................................70 RESULTS ..................................................................................................81 DISCUSSION............................................................................................97
Load more

Recommended publications
  • Hemiscyllium Ocellatum), with Emphasis on Branchial Circulation Kåre-Olav Stensløkken*,1, Lena Sundin2, Gillian M
    The Journal of Experimental Biology 207, 4451-4461 4451 Published by The Company of Biologists 2004 doi:10.1242/jeb.01291 Adenosinergic and cholinergic control mechanisms during hypoxia in the epaulette shark (Hemiscyllium ocellatum), with emphasis on branchial circulation Kåre-Olav Stensløkken*,1, Lena Sundin2, Gillian M. C. Renshaw3 and Göran E. Nilsson1 1Physiology Programme, Department of Molecular Biosciences, University of Oslo, PO Box 1041, NO-0316 Oslo Norway and 2Department of Zoophysiology, Göteborg University, SE-405 30 Göteborg, Sweden and 3Hypoxia and Ischemia Research Unit, School of Physiotherapy and Exercise Science, Griffith University, PMB 50 Gold coast Mail Centre, Queensland, 9726 Australia *Author for correspondence (e-mail: [email protected]) Accepted 17 September 2004 Summary Coral reef platforms may become hypoxic at night flow in the longitudinal vessels during hypoxia. In the during low tide. One animal in that habitat, the epaulette second part of the study, we examined the cholinergic shark (Hemiscyllium ocellatum), survives hours of severe influence on the cardiovascular circulation during severe hypoxia and at least one hour of anoxia. Here, we examine hypoxia (<0.3·mg·l–1) using antagonists against muscarinic the branchial effects of severe hypoxia (<0.3·mg·oxygen·l–1 (atropine 2·mg·kg–1) and nicotinic (tubocurarine for 20·min in anaesthetized epaulette shark), by measuring 5·mg·kg–1) receptors. Injection of acetylcholine (ACh; –1 ventral and dorsal aortic blood pressure (PVA and PDA), 1·µmol·kg ) into the ventral aorta caused a marked fall in heart rate (fH), and observing gill microcirculation using fH, a large increase in PVA, but small changes in PDA epi-illumination microscopy.
    [Show full text]
  • Assessing Interacting Global Change Stressors Via Experimental Studies on Sharks
    W&M ScholarWorks VIMS Articles Virginia Institute of Marine Science 10-16-2020 The power struggle: assessing interacting global change stressors via experimental studies on sharks Ian A. Bouyoucos Sue-Ann Watson Serge Planes Colin A. Simpfendorfer Gail D. Schwieterman Virginia Institute of Marine Science See next page for additional authors Follow this and additional works at: https://scholarworks.wm.edu/vimsarticles Part of the Aquaculture and Fisheries Commons, and the Marine Biology Commons Recommended Citation Bouyoucos, Ian A.; Watson, Sue-Ann; Planes, Serge; Colin A. Simpfendorfer; Schwieterman, Gail D.; and et al, The power struggle: assessing interacting global change stressors via experimental studies on sharks (2020). Scientific Reports, 10, 19887. doi: 10.1038/s41598-020-76966-7 This Article is brought to you for free and open access by the Virginia Institute of Marine Science at W&M ScholarWorks. It has been accepted for inclusion in VIMS Articles by an authorized administrator of W&M ScholarWorks. For more information, please contact [email protected]. Authors Ian A. Bouyoucos, Sue-Ann Watson, Serge Planes, Colin A. Simpfendorfer, Gail D. Schwieterman, and et al This article is available at W&M ScholarWorks: https://scholarworks.wm.edu/vimsarticles/2009 www.nature.com/scientificreports OPEN The power struggle: assessing interacting global change stressors via experimental studies on sharks Ian A. Bouyoucos1,2*, Sue‑Ann Watson1,3, Serge Planes2,4, Colin A. Simpfendorfer5, Gail D. Schwieterman6, Nicholas M. Whitney7 & Jodie L. Rummer1 Ocean warming and acidifcation act concurrently on marine ectotherms with the potential for detrimental, synergistic efects; yet, efects of these stressors remain understudied in large predatory fshes, including sharks.
    [Show full text]
  • Reef Fishes of the Bird's Head Peninsula, West
    Check List 5(3): 587–628, 2009. ISSN: 1809-127X LISTS OF SPECIES Reef fishes of the Bird’s Head Peninsula, West Papua, Indonesia Gerald R. Allen 1 Mark V. Erdmann 2 1 Department of Aquatic Zoology, Western Australian Museum. Locked Bag 49, Welshpool DC, Perth, Western Australia 6986. E-mail: [email protected] 2 Conservation International Indonesia Marine Program. Jl. Dr. Muwardi No. 17, Renon, Denpasar 80235 Indonesia. Abstract A checklist of shallow (to 60 m depth) reef fishes is provided for the Bird’s Head Peninsula region of West Papua, Indonesia. The area, which occupies the extreme western end of New Guinea, contains the world’s most diverse assemblage of coral reef fishes. The current checklist, which includes both historical records and recent survey results, includes 1,511 species in 451 genera and 111 families. Respective species totals for the three main coral reef areas – Raja Ampat Islands, Fakfak-Kaimana coast, and Cenderawasih Bay – are 1320, 995, and 877. In addition to its extraordinary species diversity, the region exhibits a remarkable level of endemism considering its relatively small area. A total of 26 species in 14 families are currently considered to be confined to the region. Introduction and finally a complex geologic past highlighted The region consisting of eastern Indonesia, East by shifting island arcs, oceanic plate collisions, Timor, Sabah, Philippines, Papua New Guinea, and widely fluctuating sea levels (Polhemus and the Solomon Islands is the global centre of 2007). reef fish diversity (Allen 2008). Approximately 2,460 species or 60 percent of the entire reef fish The Bird’s Head Peninsula and surrounding fauna of the Indo-West Pacific inhabits this waters has attracted the attention of naturalists and region, which is commonly referred to as the scientists ever since it was first visited by Coral Triangle (CT).
    [Show full text]
  • Reef Fishes of the Bird's Head Peninsula, West Papua, Indonesia
    Check List 5(3): 587–628, 2009. ISSN: 1809-127X LISTS OF SPECIES Reef fishes of the Bird’s Head Peninsula, West Papua, Indonesia Gerald R. Allen 1 Mark V. Erdmann 2 1 Department of Aquatic Zoology, Western Australian Museum. Locked Bag 49, Welshpool DC, Perth, Western Australia 6986. E-mail: [email protected] 2 Conservation International Indonesia Marine Program. Jl. Dr. Muwardi No. 17, Renon, Denpasar 80235 Indonesia. Abstract A checklist of shallow (to 60 m depth) reef fishes is provided for the Bird’s Head Peninsula region of West Papua, Indonesia. The area, which occupies the extreme western end of New Guinea, contains the world’s most diverse assemblage of coral reef fishes. The current checklist, which includes both historical records and recent survey results, includes 1,511 species in 451 genera and 111 families. Respective species totals for the three main coral reef areas – Raja Ampat Islands, Fakfak-Kaimana coast, and Cenderawasih Bay – are 1320, 995, and 877. In addition to its extraordinary species diversity, the region exhibits a remarkable level of endemism considering its relatively small area. A total of 26 species in 14 families are currently considered to be confined to the region. Introduction and finally a complex geologic past highlighted The region consisting of eastern Indonesia, East by shifting island arcs, oceanic plate collisions, Timor, Sabah, Philippines, Papua New Guinea, and widely fluctuating sea levels (Polhemus and the Solomon Islands is the global centre of 2007). reef fish diversity (Allen 2008). Approximately 2,460 species or 60 percent of the entire reef fish The Bird’s Head Peninsula and surrounding fauna of the Indo-West Pacific inhabits this waters has attracted the attention of naturalists and region, which is commonly referred to as the scientists ever since it was first visited by Coral Triangle (CT).
    [Show full text]
  • Coral Reef in the Pacific Ocean
    C: 85 M:100 Y:0 K:0 C: 80 M:100 Y:0 K:0 C: 0 M:36 Y:100 K:0 C: 0 M:50 Y:100 K:0 C:0 M:66 Y:100 K:0 Jump into the cockpit and take flight with Pilot books. Your journey will take you on high-energy adventures as you learn about all that is wild, weird, fascinating, and fun! C: 0 M:50 Y:100 K:0 C: 0 M:36 Y:100 K:0 C: 80 M:100 Y:0 K:0 C:0 M:66 Y:100 K:0 C: 85 M:100 Y:0 K:0 This edition first published in 2013 by Bellwether Media, Inc. No part of this publication may be reproduced in whole or in part without written permission of the publisher. For information regarding permission, write to Bellwether Media, Inc., Attention: Permissions Department, 5357 Penn Avenue South, Minneapolis, MN 55419. Library of Congress Cataloging-in-Publication Data Green, Sara, 1964- The blacktip reef shark / by Sara Green. pages cm. -- (Pilot. Shark fact files) Summary: “Engaging images accompany information about the blacktip reef shark. The combination of high-interest subject matter and narrative text is intended for students in grades 3 through 7” --Provided by publisher. Includes bibliographical references and index. ISBN 978-1-60014-867-5 (hardcover : alk. paper) 1. Blacktip shark--Juvenile literature. I. Title. QL638.95.C3G737 2013 597.3’4--dc23 2012029806 Text copyright © 2013 by Bellwether Media, Inc. PILOT and associated logos are trademarks and/or registered trademarks of Bellwether Media, Inc.
    [Show full text]
  • Blacktip Reef Sharks, Carcharhinus Melanopterus, Have High Genetic Structure and Varying Demographic Histories in Their Indopaci
    Molecular Ecology (2014) 23, 5193–5207 doi: 10.1111/mec.12936 Blacktip reef sharks, Carcharhinus melanopterus, have high genetic structure and varying demographic histories in their Indo-Pacific range THOMAS M. VIGNAUD,* JOHANN MOURIER,* JEFFREY A. MAYNARD,*† RAPHAEL LEBLOIS,‡ JULIA SPAET,§ ERIC CLUA,¶ VALENTINA NEGLIA* and SERGE PLANES* *Laboratoire d’Excellence “CORAIL”, USR 3278 CNRS – EPHE, CRIOBE, BP 1013 - 98 729 Papetoai, Moorea, Polynesie, Franßcaise, †Department of Ecology and Evolutionary Biology, Cornell University, E241 Corson Hall, Ithaca, NY 14853, USA, ‡INRA, UMR1062 CBGP, F-34988 Montferrier-sur-Lez, France, §Red Sea Research Center, King Abdullah University of Science and Technology, 23955-6900 Thuwal, Saudi Arabia, ¶French Ministry of Agriculture and Fisheries, 75007 Paris, France Abstract For free-swimming marine species like sharks, only population genetics and demo- graphic history analyses can be used to assess population health/status as baseline population numbers are usually unknown. We investigated the population genetics of blacktip reef sharks, Carcharhinus melanopterus; one of the most abundant reef-associ- ated sharks and the apex predator of many shallow water reefs of the Indian and Pacific Oceans. Our sampling includes 4 widely separated locations in the Indo-Pacific and 11 islands in French Polynesia with different levels of coastal development. Four- teen microsatellite loci were analysed for samples from all locations and two mito- chondrial DNA fragments, the control region and cytochrome b, were examined for 10 locations. For microsatellites, genetic diversity is higher for the locations in the large open systems of the Red Sea and Australia than for the fragmented habitat of the smaller islands of French Polynesia.
    [Show full text]
  • SHARK FACTS There Are 510 Species of Sharks
    1 SHARK FACTS There are 510 species of sharks. Let’s learn more about a few of them. Common Six-gilled Thresher Shark Shark • Known for its 10 foot tail • Can grow up to 16 feet long • Stuns and herds fish with its long tail • Has six pairs of gills instead of the average of five • Warm blooded • Has one dorsal fin at the back of its body • Feeds on squid and schooling fish • Also known as cow shark or mud shark • Prefers to stay towards the top of deep bodies • Deep water shark of water Shortfin Great Mako Hammerhead Shark Shark • Bluish gray on top part of body and white on • Eyes are at opposite sides of its rectangular the belly shaped head • Has extremely sharp teeth, that stick out even when • Feeds on crustaceans, octopuses, rays and its mouth is shut small sharks • Feeds on sharks, swordfish and tuna • Usually found around tropical reefs • Jumps high in the air to escape fishing hooks • Can give birth to over 40 pups in one litter • Fastest of all the sharks as it can swim over 30 mph • Has a heigtened sense of electro-reception 2 SHARK FACTS Bull Nurse Shark Shark • Can grow up to 11 feet long and over 200 pounds • Has long, fleshy appendages called barbels that hang below its snout • Gray to brown in color with a white belly • Feeds on crab, lobster, urchins and fish • Feeds on fish, dolphins, sea turtles and other sharks • Usually found near rocky reefs, mudflats • Found in fresh and salt water and sandbars • Aggressive species • Enjoys laying on the ocean floor • Nocturnal animal Great Epaulette White Shark Shark • Can grow
    [Show full text]
  • Species Carcharhinus Brachyurus (Günther, 1870
    FAMILY Carcharhinidae Jordan & Evermann, 1896 - requiem sharks [=Triaenodontini, Prionidae, Cynocephali, Galeocerdini, Carcharhininae, Eulamiidae, Loxodontinae, Scoliodontinae, Galeolamnidae, Rhizoprionodontini, Isogomphodontini] GENUS Carcharhinus Blainville, 1816 - requiem sharks [=Aprion, Aprionodon, Bogimba, Carcharias, Eulamia, Galeolamna, Galeolamnoides, Gillisqualus, Gymnorhinus, Hypoprion, Hypoprionodon, Isoplagiodon, Lamnarius, Longmania, Mapolamia, Ogilamia, Platypodon, Pterolamia, Pterolamiops, Uranga, Uranganops] Species Carcharhinus acarenatus Moreno & Hoyos, 1983 - Moroccan shark Species Carcharhinus acronotus (Poey, 1860) - blacknose shark [=remotus] Species Carcharhinus albimarginatus (Rüppell, 1837) silvertip shark [=platyrhynchus] Species Carcharhinus altimus (Springer, 1950) - bignose shark [=radamae] Species Carcharhinus amblyrhynchoides (Whitley, 1934) - graceful shark Species Carcharhinus amblyrhynchos (Bleeker, 1856) - grey reef shark [=coongoola, fowleri, nesiotes, tufiensis] Species Carcharhinus amboinensis (Müller & Henle, 1839) - Java shark [=brachyrhynchos, henlei, obtusus] Species Carcharhinus borneensis (Bleeker, 1858) - Borneo shark Species Carcharhinus brachyurus (Günther, 1870) - copper shark, bronze whaler, narrowtooth shark [=ahenea, improvisus, lamiella, remotoides, rochensis] Species Carcharhinus brevipinna (Müller & Henle, 1839) - great blacktip shark [=brevipinna B, calamaria, caparti, johnsoni, maculipinnis, nasuta] Species Carcharhinus cautus (Whitley, 1945) - nervous shark Species Carcharhinus
    [Show full text]
  • Blacktip Reef Sharks by Grace Hansen
    Blacktip Reef Sharks by Grace Hansen Abdo SHARKS Kids abdopublishing.com Published by Abdo Kids, a division of ABDO, PO Box 398166, Minneapolis, Minnesota 55439. Copyright © 2016 by Abdo Consulting Group, Inc. International copyrights reserved in all countries. No part of this book may be reproduced in any form without written permission from the publisher. Printed in the United States of America, North Mankato, Minnesota. 102015 012016 Photo Credits: Animals Animals, iStock, Seapics.com, Shutterstock, Thinkstock Production Contributors: Teddy Borth, Jennie Forsberg, Grace Hansen Design Contributors: Laura Rask, Dorothy Toth Library of Congress Control Number: 2015941989 Cataloging-in-Publication Data Hansen, Grace. Blacktip reef sharks / Grace Hansen. p. cm. -- (Sharks) ISBN 978-1-68080-150-7 (lib. bdg.) Includes index. 1. Blacktip shark--Juvenile literature. I. Title. 597.3/4--dc23 2015941989 Table of Contents Blacktip Reef Sharks . 4 Glossary . 23 Food & Hunting . 12 Index . 24 Baby Blacktip Reef Sharks . 18 Abdo Kids Code . 24 More Facts . 22 Blacktip Reef Sharks Blacktip reef sharks live in warm ocean waters . They live in bays and coral reefs near coasts . 4 5 The blacktip reef shark has large eyes . It has a short round nose . 6 7 At first glance, it looks like other sharks . The top half of its body is gray . The bottom half is white . 8 9 But this shark has some special features! It has black markings on the tips of its fins . It has white lines on its sides . 10 11 Food & Hunting Blacktip reef sharks have rows of sharp teeth . Their teeth are great for catching prey .
    [Show full text]
  • Species Composition of Elasmobranchs in the Surface and Subsurface Gillnet Operation in the Northern Arabian Sea
    __________________________________________________IOTC-2019-WPEB15-13 Species composition of elasmobranchs in the surface and subsurface gillnet operation in the Northern Arabian Sea Muhammad Moazzam WWF-Pakistan, Karachi, Pakistan ([email protected]) Abstract Sharks form important part of bycatch of the tuna gillnet operations in Pakistan. WWF- Pakistan introduced subsurface gillnetting in 2014 in which gillnet are placed 1.4 to 2 m below the sea surface. Fishing fleet engaged in tuna gillnetting adopted subsurface gillnetting and by January 2016 entire tuna fleet was converted in subsurface gillnetting. Catch of endangered, threatened and protected (ETP) species such as dolphins and sea turtles were observed to be much lower in subsurface gillnet as compared to surface operations. Sharks are among the other ETP species whose catches were dropped in subsurface gillnet as compared to surface operations. It was observed that overall shark catches were 15.06 % lower in the subsurface gillnet operation as compared to surface placement of gillnets. A marked seasonality was observed in case of dominating species including mako and silky shark. Catches of mako sharks was observed to be about 8.65 % higher in subsurface gillnets as compared to surface gillnets. Introduction Sharks are considered as an important bycatch group of tuna gillnet fishing in Pakistan and other part of the Arabian Sea (Koya, 2018; Shahifar, 2018, Khan, 2013; Moazzam, 2013; Shahid et al., 2015, 2016). In Pakistan, gillnets consisting of monofilament and multifilament are used for catching tuna and tuna like species. Monofilament net is mainly used for catching neritic tuna in coastal waters whereas multifilament nylon nets are used for catching longtail tuna (Thunnus tonggol), yellowfin tuna (Thunnus albacares) and skipjack tuna (Katsuwonus pelamis) in the offshore waters.
    [Show full text]
  • Shark and Ray Identification Manual for Observers and Crew of the Western and Central Pacific Tuna Fisheries
    Shark and ray identification manual for observers and crew of the western and central Pacific tuna fisheries Shark and ray identification manual for observers and crew of the western and central Pacific tuna fisheries Timothy Park, Lindsay Marshall, Aymeric Desurmont, Boris Colas and Neville Smith Noumea, New Caledonia, October 2019 © Pacific Community (SPC) 2019 All rights for commercial/for profit reproduction or translation, in any form, reserved. SPC authorises the partial reproduction or translation of this material for scientific, educational or research purposes, provided that SPC and the source document are properly acknowledged. Permission to reproduce the document and/or translate in whole, in any form, whether for commercial/for profit or non-profit purposes, must be requested in writing. Original SPC artwork may not be altered or separately published without permission. Original text: English Pacific Community Cataloguing-in-publication data Park, T. Shark and ray identification manual for observers and crew of the western and central Pacific tuna fisheries / Timothy Park, Lindsay Marshall, Aymeric Desurmont, Boris Colas and Neville Smith 1. Sharks — Oceania — Identification. 2. Rays (Fishes) — Oceania — Identification. 3. Fishes — Identification. 4. Shark fisheries — Oceania. 5. Ray fisheries — Oceania. I. Park, T. II. Marshall, Lindsay III. Desurmont, Aymeric IV. Colas, Boris V. Smith, Neville VI. Title VII. Pacific Community 639.20995 AACR2 ISBN: 978-982-00-1187-8 This document may be cited as: Park T., Marshall L., Desurmont A., Colas B. and Smith N. 2019. Shark and ray identification manual for observers and crew of the western and central Pacific tuna fisheries. Noumea, New Caledonia: Pacific Community.
    [Show full text]
  • Tropical Archaeology Research Laboratory
    Tropical Archaeology Research Laboratory Comparative Fish Reference Collection: Developing a Resource for Identifying Marine Fish Remains in Archaeological Deposits in Tropical Australasia Helene Tomkins, Daniel Rosendahl and Sean Ulm Department of Anthropology, Archaeology and Sociology, School of Arts and Social Sciences, James Cook University, PO Box 6811, Cairns QLD 4870, Australia [email protected], [email protected], [email protected] This paper outlines the methods adopted for creating a fish osteological reference collection for tropical Australasia. This collection currently contains bones from 52 fish representing 35 different species found in the Gulf of Carpentaria, Australia. This developing collection has become a valuable resource for zooarchaeological analyses in the Queensland, Torres Strait and Papua New Guinea tropical coastal zone. Ongoing development of the collection to include specimens from a wider geographic area will further support fish bone research across the region. Introduction platform enables users to view photographs of fish bones Coastal archaeological sites in tropical Australasia contained in the reference collections. At present there are (particularly shell middens) characteristically contain only a few images of selected anatomical elements accumulations of marine faunal remains, such as available for each species, and unfortunately otoliths (the molluscan shells and animal bones (especially fish, most diagnostic elements of all) are absent. As more marine mammals and marine reptiles). While the majority images are added to the database its value to scientists as of faunal material is molluscan in nature, there is usually a research tool will continue to grow. also a small percentage of fish bone, which has the Despite the excellent quality of these collections, not potential to significantly inform discussions regarding all regions have equal representation owing to the human foraging choices and environmental change.
    [Show full text]