DOCSLIB.ORG

Ecosystem Services Provided by Modiolus Modiolus Biogenic Reefs

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ecosystem Services Provided by Modiolus Modiolus Biogenic Reefs Ecosystem services provided by Modiolus modiolus biogenic reefs Flora Kent B.Sc. A thesis submitted for the degree of Doctor of Philosophy School of Life Sciences Heriot-Watt University Edinburgh UK July 2015 The copyright in this thesis is owned by the author. Any quotation from the thesis or use of any of the information contained in it must acknowledge this thesis as the source of the quotation or information. Abstract Ecological field studies were carried out in situ on Modiolus modiolus biogenic reefs throughout the UK to quantify the functional importance of these habitats and the associated ecosystem services that they provide to society. Using a combination of techniques, including Underwater Visual Censuses (UVCs), video transects and pot fishing, the key species associated with M. modious reefs were found to be Buccinum undatum and Aequipecten opercularis. B. undatum catches were three times higher on the M. modiolus reefs compared to adjacent habitats and the UVCs showed that A. opercularis were five times more abundant on M. modiolus reef sites. By providing a habitat for these commercially important shellfish, M. modiolus reefs act as an Essential Fish Habitat and support sustainable livelihoods. M. modiolus are ecosystem engineers and can occur as dense aggregations, which form raised, three dimensional reef structures on the seabed. A new method was developed to measure M. modiolus biodeposition rates in situ and this provides the first evidence of the scale at which M. modiolus are able to enhance sedimentation and contribute to the downward flux of material to the seabed. M. modiolus biogenic reefs are recognised as biodiversity hotspots and protected in Marine Protected Areas. However, under controlled conditions when subject to seawater temperatures above those experienced in the wild, byssus thread production is compromised whilst biodeposition rates are modified also. M. modiolus reefs at the southern limit of their known distribution will continue to exist in the short term but with predicted increased seawater temperature, M. modiolus may not be able to function to their full ability. These habitats are vulnerable to physical impact from mobile fishing gear and the results presented here suggest that reef recovery through byssus attachment and clump formation would be limited, especially in southern populations. Management of protected reefs should take this into account and ensure that ecosystem resilience is maximised through well enforced management measures. Acknowledgements I would like to thank my supervisors, Bill Sanderson and Kim Last for their advice and encouragement. I am sincerely grateful for the support of the Heriot-Watt Scientific Dive Team especially, Dan Harries, Hamish Mair, Rob Cook, Jo Porter, Sally Rouse and Bill Sanderson, as without their help and positivity the fieldwork would not have been possible or as enjoyable. Many thanks also to skippers Colin Moore, Bob Anderson and Peter Jones for their skill and advice. I am also grateful to Jason Newton at SUERC for his assistance with the stable isotope project as well as Christine Beveridge and Kieran Tulbure for their assistance in the aquarium at SAMS. Thanks to Mark Gray for facilitating a successful partnership with the Pen Llŷn fishermen and providing access to fishing vessels. That leads me on to thank the main funders of this PhD, which were MASTS and Heriot-Watt University as well as Seafish who supported the whelk fishing project. Many thanks also to Charlie Lindenbaumn and Karen Robinson at Natural Resources Wales for their help with habitat mapping. Finally, I would like to thank my friends and family for encouraging me to take on this challenge and supporting me throughout the PhD. ACADEMIC REGISTRY Research Thesis Submission Name: Flora Kent School/PGI: School of Life Sciences Version: (i.e. Final Degree Sought PhD First, Resubmission, (Award and Final) Marine Ecology Subject area) Declaration In accordance with the appropriate regulations I hereby submit my thesis and I declare that: 1) the thesis embodies the results of my own work and has been composed by myself 2) where appropriate, I have made acknowledgement of the work of others and have made reference to work carried out in collaboration with other persons 3) the thesis is the correct version of the thesis for submission and is the same version as any electronic versions submitted*. 4) my thesis for the award referred to, deposited in the Heriot-Watt University Library, should be made available for loan or photocopying and be available via the Institutional Repository, subject to such conditions as the Librarian may require 5) I understand that as a student of the University I am required to abide by the Regulations of the University and to conform to its discipline. * Please note that it is the responsibility of the candidate to ensure that the correct version of the thesis is submitted. Signature of Date: 23/10/2015 Candidate: Submission Submitted By (name in capitals): Signature of Individual Submitting: Date Submitted: For Completion in the Student Service Centre (SSC) Received in the SSC by (name in capitals): Method of Submission (Handed in to SSC; posted through internal/external mail): E-thesis Submitted (mandatory for final theses) Signature: Date: Table of Contents Chapter 1. General Introduction .................................................................................... 1 Ecosystem Goods and Services ................................................................................. 2 Essential Fish Habitat ................................................................................................ 5 Nutrient Cycling ........................................................................................................ 7 Sediment Stabilisation and Accumulation ................................................................ 7 Biodeposition and Filter Feeding .............................................................................. 8 Reef Formation........................................................................................................ 10 Anthropogenic Impacts on Marine Ecosystems ...................................................... 11 Objectives and Thesis Structure .................................................................................. 13 Chapter 2. Key megafaunal species associated with Modiolus modiolus reefs .............. 15 Abstract ..................................................................................................................... 15 Introduction ................................................................................................................. 15 Methods ....................................................................................................................... 19 Modiolus modiolus Reef Food Web Analysis - Stable Isotopes ............................. 22 Data Analysis .......................................................................................................... 23 Results ....................................................................................................................... 26 Habitat Surveys ....................................................................................................... 26 Underwater Visual Censuses – Megafauna Transects ............................................ 27 Drop Down Video Transects – Megafauna Transects ............................................ 28 Foodweb Analysis ................................................................................................... 31 Biological Traits Analysis ....................................................................................... 32 Discussion ................................................................................................................... 33 Chapter 3. The functional role of a horse mussel (Modiolus modiolus) reef as a habitat for the common whelk, Buccinum undatum. .................................................................. 37 Abstract ....................................................................................................................... 37 Introduction ................................................................................................................. 37 Methods ....................................................................................................................... 39 Age Determination - Growth Rate .......................................................................... 42 Migration ................................................................................................................. 43 Data Analysis .......................................................................................................... 43 Results ......................................................................................................................... 44 Growth Rates ........................................................................................................... 48 Tagged whelks ........................................................................................................ 50 Discussion ................................................................................................................... 50 Chapter 4. In situ measurements of sedimentation and biodeposition on a Modiolus modiolus reef ................................................................................................................... 54 Abstract ......................................................................................................................
Load more

Recommended publications
  • Side-Scan-Sonar Survey of the Horse Mussel (Modiolus Modiolus) Beds Off the Point of Ayre (August 2008)
    Side-scan-sonar survey of the Horse mussel (Modiolus modiolus) beds off the Point of Ayre (August 2008) Hilmar Hinz, Lee Murray & Michel J. Kaiser School of Ocean Sciences, College of Natural Sciences, Bangor University To cite this report: Hinz, H., Murray, L. & Kaiser, M.J. (2008) Side-scan-sonar survey of the Horse mussel (Modiolus modiolus) beds off the Point of Ayre (August 2008). Fisheries & Conservation report No. 4, Bangor University. Pp. 19. 1 INTRODUCTION Modiolus modiolus (horse mussels) can occur locally in high abundances leading to the formation biogenic reef structures. These structures have a rich associated fauna, in particular emergent epifauna such as soft corals, sponges, anemones, ascidians, hydroids and bryozoans. Also tubeworms, brittlestars, urchins, starfish, barnacles, crabs, whelks and scallops commonly occur in elevated abundance on Modiolus reefs (Holt et al. 1998 and references therein). Due to the occurrence of scallops among the Modiolus reef matrix, scallop dredging has been identified as a major threat to this complex habitat. Modiolus beds are considered to have been eroded by fishing in other parts of the Isle of Man such as the Modiolus beds off Dreswick Point. Furthermore aggregate extraction may be a potential thread to the Modiolus beds through direct physical disturbance or indirectly via changes in local hydrodynamic conditions that affect food supply and larval recruitment. Within UK waters Modiolus reefs are of conservation interest and are protected within Special Areas of Conservation (SAC). No bylaws are in place to protect Modiolus reefs around the Isle of Man. The Modiolus (Modiolus modiolus) bed off the Point of Ayre was surveyed with side-scan-sonar and video/stills camera tows as part of a larger habitat mapping survey conducted by the School of Ocean Sciences onboard the R.V.
    [Show full text]
  • Outer Ards Modiolus Modiolus Report
    R Assessment of Outer Ards Modiolus modiolus biogenic reefs against Special Area of Conservation (SAC) criteria JULY 2016 A report from the Fisheries and Aquatic Ecosystems Branch, Agri-food and Biosciences Institute to The Department of Agriculture, Environment and Rural Affairs (Northern Ireland) Document version control: Version Issue date Modifier Note Issued to and date 1.0 31/03/2016 AFBI-AC First draft for review DAERA & MS: 31/03/2016 1.1 19/05/2016 AFBI-AC Second draft for review DAERA & MS: 19/05/2016 1.2 19/07/2016 AFBI-AC Final draft for sign off following MS: 19/07/2016 receipt of comments 22/06/2016 1.3 19/07/2016 AFBI-AC Final version DAERA: 20/07/2016 Further information Dr. Annika Clements Seabed Habitat Mapping Project Leader Fisheries & Aquatic Ecosystems Branch Newforge Lane Belfast BT9 5PX Tel: +44(0)2890255153 Email: [email protected] DAERA Client Officer Joe Breen DAERA, Marine Conservation and Reporting Team Marine & Fisheries Division Portrush Coastal Zone 8 Bath Road PORTRUSH BT56 8AP Tel: +44(0)2870823600 (ext31) Email: [email protected] The GIS project “Outer_Ards_Modiolus_2016.mxd” should be available for use in conjunction with this report. Recommended citation: AFBI, 2016. Special Area of Conservation Designation Assessment of Outer Ards Modiolus modiolus Biogenic Reef. Report to the Department of Agriculture, Environment and Rural Affairs, Northern Ireland. Acknowledgements The author wishes to thank Adele Boyd and Matthew Service (AFBI) for data provision, James McArdle (AFBI), Katie Lilley (Ulster University placement student with AFBI) and Clara Alvarez Alonso (DAERA) and the master and crew of the R.V.
    [Show full text]
  • HORSE MUSSEL BEDS Image Map
    PRIORITY MARINE FEATURE (PMF) - FISHERIES MANAGEMENT REVIEW Feature HORSE MUSSEL BEDS Image Map Image: Rob Cook Description Characteristics - Horse mussels (Modiolus modiolus) may occur as isolated individuals or aggregated into beds in the form of scattered clumps, thin layers or dense raised hummocks or mounds, with densities reaching up to 400 individuals per m2 (Lindenbaum et al., 2008). Individuals can grow to lengths >150 mm and live for >45 years (Anwar et al., 1990). The mussels attach to the substratum and to each other using tough threads (known as byssus) to create a distinctive biogenic habitat (or reef) that stabilises seabed sediments and can extend over several hectares. Silt, organic waste and shell material accumulate within the structure and further increase the bed height. In this way, horse mussel beds significantly modify sedimentary habitats and provide substrate, refuge and ecological niches for a wide variety of organisms. The beds increase local biodiversity and may provide settling grounds for commercially important bivalves, such as queen scallops. Fish make use of both the higher production of benthic prey and the added structural complexity (OSPAR, 2009). Definition - Beds are formed from clumps of horse mussels and shells covering more than 30% of the seabed over an area of at least 5 m x 5 m. Live adult horse mussels must be present. The horse mussels may be semi-infaunal (partially embedded within the seabed sediments - with densities of greater than 5 live individuals per m2) or form epifaunal mounds (standing clear of the substrate with more than 10 live individuals per clump) (Morris, 2015).
    [Show full text]
  • Modiolus Modiolus Class: Bivalvia Order: Mytiloida Family: Mytilidae
    Shells are all along the nearby shoreline. Modiolus modiolus Class: Bivalvia Order: Mytiloida Family: Mytilidae Genus: Modiolus Distribution Its global range includes the coasts of Japan, Iceland, Europe, This species is widely north-western Africa and the Mediterranean Sea. It occurs on distributed in the northern the European seaboard of the Atlantic Ocean from the United hemisphere. It is found Kingdom northwards. It occupies all of the North Sea and along the Atlantic coast of extends south to the Bay of Biscay. There are large beds of these North America, from the mussels along the coast of Scotland. Arctic Ocean to Florida, They occur on both the west and east coasts of Canada but are and along the Pacific coast, far greater in number all along the eastern seaboard. They from the Arctic Ocean to extend from Nova Scotia up into the Arctic Ocean. California. It can be seen singly usually in rough ground but also in huge Habitat beds. It can be found on the lower shore in rock pools or in The horse mussel is found laminarian (seaweed) holdfasts but more common subtidally to partly buried in soft depths approaching 300m. It is found from low tide mark to sediments or coarse depths of 50 metres in British waters and 80 metres off the coast grounds or attached to hard of Nova Scotia. Individuals have been found at depths of up to substrata, forming clumps 280 m. Water movement appears to be an important factor in or extensive beds or reefs. the build up of many of the denser reef areas, the majority being found in areas of moderate to strong tidal currents.
    [Show full text]
  • SPECIES INFORMATION SHEET Modiolus Modiolus
    SPECIES INFORMATION SHEET Modiolus modiolus English name: Scientific name: Northern horsemussel Modiolus modiolus Taxonomical group: Species authority: Class: Bivalvia (Linnaeus, 1758) Order: Mytiloida Family: Mytilidae Subspecies, Variations, Synonyms: Generation length: Modiola modiolus 30–35 years Mytilus modiolus Linnaeus, 1758 Past and current threats (Habitats Directive Future threats (Habitats Directive article 17 article 17 codes): codes): Fishing (bottom trawling; F02.02.01), Fishing (bottom trawling; F02.02.01), Construction (stone fishing; J03.01), Construction (C03.03), Eutrophication (H01.05), Eutrophication (H01.05) Climate change (M01) IUCN Criteria: HELCOM Red List VU A2c Category: Vulnerable Global / European IUCN Red List Category Habitats Directive: NE/NE Modiolus-reefs is a part of the Habitats Directive habitat 1170 (Reefs) Protection and Red List status in HELCOM countries: Denmark –/–, Estonia –/–, Finland –/–, Germany –/2 (Endangered, incl. North Sea), Latvia –/–, Lithuania –/–, Poland –/–, Russia –/–, Sweden –/LC Distribution and status in the Baltic Sea region Modiolus modiolus is a long living and large bivalve that lives in the western Baltic Sea in hard bottom habitats. It has suffered from various human activities that have destroyed or deteriorated its habitats and the population has declined in the HELCOM area. In general, M. modiolus is an arctic-boreal species, and its distribution ranges from the seas around Scandinavia (including Skagerrak & Kattegat) and Iceland south to the Bay of Biscay. Modiolus
    [Show full text]
  • The Revolution of Science Through Scuba
    The Revolution of Science through Scuba Scuba Revolutionizes Marine Science Jon D. Witman, Paul K. Dayton, Suzanne N. Arnold, Robert S. Steneck, and Charles Birkeland ABSTRACT. Scuba provides scientists with the capacity for direct observation and experimental manipulation in underwater research. Technology allows broader- scale observations and measure- ments such as satellite detection of coral bleaching up to a global scale and LIDAR determination of reef- wide topographic complexity on landscape to regional scales. Scuba- based observations provide a means of ground truthing these broad-scale technologies. For example, ground truthing the read- ings on a scale as small as a video transect taken at 50 cm above the substratum can reveal that the previously confident interpretation of the transect data from the video analysis was inaccurate. At the opposite end of the spatial continuum, electron microscopy and DNA analysis provide the ca- pacity to determine species traits at a scale too fine for direct observation, while observations made during the collection of samples by scuba can provide vital information on the context of the tissue sample collection. Using our hands and eyes to set up experiments under water is less expensive and more adaptable to the unexpected topographic complexities of hard substratum habitats than doing so with submersibles, robots, or via cables from ships. The most profound contribution of scuba to underwater science, however, is the otherwise unobtainable insights provided by direct observation. Ecology is not always predictable from species traits because the behavioral or interactive charac- teristics of marine organisms together cause them to function in surprising and often synergistic ways.
    [Show full text]
  • An Access-Dictionary of Internationalist High Tech Latinate English
    An Access-Dictionary of Internationalist High Tech Latinate English Excerpted from Word Power, Public Speaking Confidence, and Dictionary-Based Learning, Copyright © 2007 by Robert Oliphant, columnist, Education News Author of The Latin-Old English Glossary in British Museum MS 3376 (Mouton, 1966) and A Piano for Mrs. Cimino (Prentice Hall, 1980) INTRODUCTION Strictly speaking, this is simply a list of technical terms: 30,680 of them presented in an alphabetical sequence of 52 professional subject fields ranging from Aeronautics to Zoology. Practically considered, though, every item on the list can be quickly accessed in the Random House Webster’s Unabridged Dictionary (RHU), updated second edition of 2007, or in its CD – ROM WordGenius® version. So what’s here is actually an in-depth learning tool for mastering the basic vocabularies of what today can fairly be called American-Pronunciation Internationalist High Tech Latinate English. Dictionary authority. This list, by virtue of its dictionary link, has far more authority than a conventional professional-subject glossary, even the one offered online by the University of Maryland Medical Center. American dictionaries, after all, have always assigned their technical terms to professional experts in specific fields, identified those experts in print, and in effect held them responsible for the accuracy and comprehensiveness of each entry. Even more important, the entries themselves offer learners a complete sketch of each target word (headword). Memorization. For professionals, memorization is a basic career requirement. Any physician will tell you how much of it is called for in medical school and how hard it is, thanks to thousands of strange, exotic shapes like <myocardium> that have to be taken apart in the mind and reassembled like pieces of an unpronounceable jigsaw puzzle.
    [Show full text]
  • Modiolus Modiolus) Biogenic Reefs: a Priority Habitat for Nature Conservation and Fisheries Benefits
    Heriot-Watt University Research Gateway Commercially important species associated with horse mussel (Modiolus modiolus) biogenic reefs: a priority habitat for nature conservation and fisheries benefits Citation for published version: Kent, F, Mair, JM, Newton, J, Lindenbaum, C, Porter, J & Sanderson, W 2017, 'Commercially important species associated with horse mussel (Modiolus modiolus) biogenic reefs: a priority habitat for nature conservation and fisheries benefits', Marine Pollution Bulletin, vol. 118, no. 1-2, pp. 71-78. https://doi.org/10.1016/j.marpolbul.2017.02.051 Digital Object Identifier (DOI): 10.1016/j.marpolbul.2017.02.051 Link: Link to publication record in Heriot-Watt Research Portal Document Version: Peer reviewed version Published In: Marine Pollution Bulletin General rights Copyright for the publications made accessible via Heriot-Watt Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy Heriot-Watt University has made every reasonable effort to ensure that the content in Heriot-Watt Research Portal complies with UK legislation. If you believe that the public display of this file breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Download date: 29. Sep. 2021 1 Commercially important species associated with horse mussel (Modiolus 2 modiolus) biogenic reefs: a habitat for biodiversity conservation and 3 fisheries benefits 4 5 Flora E. A. Kent1, James M. Mair1, Jason Newton2, Charles Lindenbaum3, Joanne S.
    [Show full text]
  • Oxygen Uptake and Transport in the Lamellibranch Mollusc Modiolus Demissus
    W&M ScholarWorks Dissertations, Theses, and Masters Projects Theses, Dissertations, & Master Projects 1975 Oxygen Uptake and Transport in the Lamellibranch Mollusc Modiolus demissus Charles Edward Booth College of William & Mary - Arts & Sciences Follow this and additional works at: https://scholarworks.wm.edu/etd Part of the Physiology Commons Recommended Citation Booth, Charles Edward, "Oxygen Uptake and Transport in the Lamellibranch Mollusc Modiolus demissus" (1975). Dissertations, Theses, and Masters Projects. Paper 1539624929. https://dx.doi.org/doi:10.21220/s2-drcj-k017 This Thesis is brought to you for free and open access by the Theses, Dissertations, & Master Projects at W&M ScholarWorks. It has been accepted for inclusion in Dissertations, Theses, and Masters Projects by an authorized administrator of W&M ScholarWorks. For more information, please contact [email protected]. OXYGEN UPTAKE MD TRANSPORT IN THE LAMELLI BRAN CK h MOLLUSC MODIOLUS DEMISSUS A Thesis Presented to The Faculty of the Department of Biology The College of wilj.iam and Mary in Virginia In Partial Fulfillment Of the Requirements for the Degree of Master of Arts by- Charles Edvard Booth 1 9 7 6 APPROVAL SHEET This thesis is submitted in partial fulfillment of the requirements for the degree of Master of Arts Author Approved s Deeember 1976 Charlotte P. Mangum <L,X 'JShuLjjL Robert E. L, Black ACKNOWLEDGMENTS I vrould like to express ray sincere gratitude and appreciation to Dr. Charlotte P. Mangum for her guidance and enthusiasm throughout the course of this study. I would, also like to thank Drs. Robert E. L. Black and Gregory M. Capelli for their careful reading and criticism of the manuscript.
    [Show full text]
  • Serpulid Reefs Where Are the Reefs?
    Serpulid Reefs N Serpulid reefs are built by the tube worm Loch Creran Serpula vermicularis which in its solitary form, SAC RA is widespread around Britain, leaving white Oban tubes on rocks and shells on the beach. Each tube houses a single worm that, when H CRE feeding, extends a double horseshoe of vibrant C crimson, orange or pink feathery tentacles to filter the water for passing plankton. In certain LO Glasgow conditions, which are not yet fully understood, the worm tubes grow up off the seabed, twisting around each other and branching to form fragile bush-like structures (reefs) up to 75 cm high and 1 m in diameter. Where are the reefs? In Loch Creran, serpulid reefs have formed around the edge of the loch in depths of 6 - 13 m below chart datum. The serpulid reefs of Loch Creran were first reported in 1882 and have recently been found to cover an area of around 108 hectares - about 100 football fields! For further information see www.argyllmarinesac.org Text: Marine and Coastal Development Unit - Argyll and Bute Council An ideal home Photography: Argyll and Bute Council, Hugh Brown, Neil MacQueen, Andrew McKenna, Paul Naylor The reefs provide protected living space and (from the book Great British Marine Animals), Graham Saunders (SNH), SNH and Colin Moore food for many other creatures such as hermit A Guide to Anchoring crabs, squat lobsters, feather stars, starfish, (Heriot-Watt University) whelks, crabs, fish, prawns and sponges. Design: DeeVA in the Loch Creran Print: Printed on environmentally friendly paper by CGL Research has shown that a typical serpulid Oban Marine Special Area reef colony can be home to over 70 different species and 2500 individual animals and plants! of Conservation Funding support from: Loch Creran Why do we need designated anchorages? A survey of Loch Creran was undertaken by Scottish Natural Heritage as part of the ongoing Site Condition Monitoring A Protected Site programme.
    [Show full text]
  • Innovation Fund Research Proposal
    Innovation Fund Research Proposal A. PROJECT TITLE Sediment tolerance and mortality thresholds of benthic habitats on the Taranaki Shelf B. PROJECT TEAM Project Leader: Investigators: Malcolm Clark, National Institute of James Bell: Victoria University of Water & Atmospheric Research (NIWA) Wellington Private Bag 14-901, Wellington 6421 Vonda Cummings: NIWA [email protected] Di Tracey: NIWA Tel: (04) 3860523 Dennis Gordon: NIWA Neill Barr: NIWA Peter Batson: University of Otago C. ABSTRACT The research in this project will determine the effects on deep-shelf benthic communities of elevated suspended sediment concentrations caused by human activities, such as seabed mining and fishing. Whereas sedimentation impacts on biological communities have been studied in very near-shore coastal environments, little information exists on tolerances of fauna from deeper shelf waters. This research will measure acute and sub-lethal physiological effects for selected marine taxa, and help establish threshold levels of suspended and settled sediment where impacts on deep-sea species become “ecologically significant”. This will subsequently provide information to mitigate or manage impacts on such benthic communities. In addition, comparisons will be made of responses of the same species from shallow and deep water to explore relative sensitivities across a range of shelf depths. The work programme involves innovative laboratory experiments to assess impacts on diverse benthic fauna (sponges, bivalves, bryozoans) which are common and ecologically important biogenic habitat formers in the South Taranaki Bight. The work will inform ecosystem-based management initiatives within the Sustainable Seas programme, and extend the programme focus to deeper shelf waters, as well as having wide relevance to deep-sea communities in general across the New Zealand region.
    [Show full text]
  • Comparative Distribution of the Fan Mussel Atrina Fragilis (Bivalvia, Pinnidae) in Protected and Trawled Areas of the North Aegean Sea (Thermaikos Gulf)
    Short Communication Mediterranean Marine Science Indexed in WoS (Web of Science, ISI Thomson) and SCOPUS The journal is available on line at http://www.medit-mar-sc.net http://dx.doi.org/10.12681/mms.317 Comparative distribution of the fan mussel Atrina fragilis (Bivalvia, Pinnidae) in protected and trawled areas of the north Aegean Sea (Thermaikos Gulf) K. FRYGANIOTIS, C. ANTONIADOU and C. CHINTIROGLOU School of Biology, Department of Zoology, Aristotle University of Thessaloniki, 54124, Greece Corresponding author: [email protected] Handling Editor: Stelios Katsanevakis Received: 23 July 2012; Accepted: 4 December 2012; Published on line: 28 February 2013 Abstract The distribution of the fan mussel Atrina fragilis was studied at two contrasting areas of the north Aegean Sea (Thermaikos Gulf): one routinely trawled and one closed to trawlers for over 25 years. Significant differences were detected between the two areas with decreased values in density and size of A. fragilis individuals at the trawled area. As habitat differences, i.e. sediment composition and bathymetry, had a non-significant effect, extensive trawling activities probably explain the observed results. Keywords: population structure, trawling impacts, bivalves, Aegean Sea. Introduction nobilis which has been traditionally exploited (Chinti- roglou et al., 2005) and is currently under strict protec- Fan mussels or pen shells are generally large bivalves, tion (Katsanevakis, 2006; Katsanevakis et al., 2008), A. triangular in shape, belonging to the Pinnidae family. fragilis is only occasionally harvested (Poutiers, 1987), They comprise the genus Pinna and Atrina; their species although often reported from fisheries discards (Batista exist as metapopulations, composed of small patches of et al., 2009; Voultsiadou et al., 2011).
    [Show full text]