DOCSLIB.ORG

Juvenile Biology and Captive Rearing of the Freshwater Pearl Mussel Margaritifera Margaritifera

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Juvenile Biology and Captive Rearing of the Freshwater Pearl Mussel Margaritifera Margaritifera Juvenile biology and captive rearing of the freshwater pearl mussel Margaritifera margaritifera Louise Lavictoire BSc. (Hons) October 2016 University of Lancaster This thesis is forsubmitted the degree in partial of Doctor fulfilment of Philosophy of the requirements ii Abstract Abstract Title: Juvenile biology and captive rearing of the freshwater pearl mussel Margaritifera margaritifera Author: Louise Lavictoire BSc. (Hons) Degree: Doctor of Philosophy Submission date: October 2016 Word count: 40,617 Captive breeding of the freshwater pearl mussel (Margaritifera margaritifera) is an important short-term strategy to conserve this critically endangered species. The aim of this thesis was to improve current knowledge of the factors affecting juvenile M. margaritifera in a captive setting, and to develop understanding of juvenile anatomy, ontogeny and the ecological requirements of juveniles in captivity. The substrate requirements of newly-excysted juveniles were investigated in an experimental flow-through system (Chapter 3) by analysing differences in survival and growth in two different substrate size clasts (0.25 - 1 mm or 1 - 2 mm), and cleaning regimes (weekly or monthly). Factors potentially affecting juvenile survival and growth were further investigated in Chapter 4. Results indicate that dissolved oxygen and flow were crucial for juveniles in this system. Investigations of juvenile anatomy and ontogeny (Chapter 5) using scanning electron microscopy have greatly improved our knowledge of the timing of key developmental stages, such as the onset of gill reflection. Analyses of gill ciliation suggest the species is capable of retaining very small particles (<2 µm diameter), offering a potential reason for why M. margaritifera is so sensitive to turbid and enriched conditions. Improving the efficiency and effectiveness of monitoring juveniles in captivity should be an objective for all rearing programmes. Batch marking of juveniles through immersion in calcein (Chapter 6) was shown to offer a quick and reliable method and has the potential to save rearing programmes time and money whilst improving juvenile monitoring. The findings of these investigations should inform other captive rearing programmes in order to improve juvenile survival. Rearing efforts should focus initially on ensuring sufficient flow and dissolved oxygen for post-excystment juveniles, before tailoring systems to ensure low-stress conditions for transforming juveniles. iii iv Contents Contents Abstract ..............................................................................................................................iii List of figures ......................................................................................................................xi List of tables ..................................................................................................................... xxi Acknowledgements ......................................................................................................... xxv Author’s declaration ...................................................................................................... xxvii Chapter 1: Introduction ...................................................................................................... 1 1.1. Background and context of freshwater bivalve conservation .................................... 2 1.2. The freshwater pearl mussel Margaritifera margaritifera ......................................... 3 1.2.1 Life history, distribution, habitat requirements and factors causing decline ..... 3 1.2.2 Taxonomy .......................................................................................................... 6 1.3. Captive rearing strategies ........................................................................................... 7 1.4. Thesis outline and objectives ................................................................................... 10 1.5. References ................................................................................................................ 13 Chapter 2: Freshwater Pearl Mussel Ark project and pilot studies ..................................... 21 2.1. Introduction .............................................................................................................. 22 2.1.1 Freshwater Pearl Mussel Ark project and the FBA captive rearing facility ...... 22 2.2. Pilot studies .............................................................................................................. 24 2.2.1 The effect of substrate size, depth and cleaning regime on growth and survival of juvenile mussels .................................................................................................... 25 2.2.2 Investigating the suitability of calcein immersion as a marking technique for juvenile mussels ........................................................................................................ 32 2.3. Conclusions .............................................................................................................. 40 2.4. References ................................................................................................................ 40 Chapter 3: Investigating the effects of substrate size and cleaning regime on growth and survival of juvenile freshwater pearl mussels Margaritifera margaritifera ....................... 43 3.1. Introduction .............................................................................................................. 44 3.1.1 Culture conditions affecting juvenile survival .................................................. 45 3.1.2 Objective of this study ..................................................................................... 47 3.2. Methods ................................................................................................................... 48 3.2.1 Experimental design ........................................................................................ 48 3.2.2 Data analysis ................................................................................................... 51 v Contents 3.3. Results ...................................................................................................................... 52 3.3.1 Survival ............................................................................................................ 52 3.3.2 Size .................................................................................................................. 57 3.3.3 Escaped mussels .............................................................................................. 63 3.4. Discussion ................................................................................................................. 64 3.4.1 Effect of substrate size ..................................................................................... 66 3.4.2 Effect of cleaning regime ................................................................................. 67 3.4.3 Effect of temperature ..................................................................................... 68 3.4.4 Conclusions and further research ................................................................... 70 3.5. References ................................................................................................................ 71 Chapter 4: Interstitial factors affecting growth and survival of juvenile freshwater pearl mussels Margaritifera margaritifera ................................................................................ 75 4.1. Introduction .............................................................................................................. 76 4.1.1 Interstitial conditions affecting juvenile mussels ............................................. 76 4.1.2 Objective of this study ..................................................................................... 78 4.2. Methods ................................................................................................................... 79 4.2.1 Experimental set-up ......................................................................................... 79 4.2.2 Chemical analyses ........................................................................................... 81 4.2.3 Flow and organic content analysis .................................................................. 83 4.2.4 Data analysis ................................................................................................... 83 4.3. Results ...................................................................................................................... 84 4.3.1 Survival ........................................................................................................... 86 4.3.2 Size .................................................................................................................. 87 4.3.3 Dissolved oxygen ............................................................................................. 91 4.3.4 Interstitial space and flow ............................................................................... 99 4.3.5 Substrate organic content and ion concentrations ........................................ 101 4.4. Discussion ............................................................................................................... 102 4.4.1 Effects on growth and survival – current investigation and comparisons over several years ..........................................................................................................
Load more

Recommended publications
  • Growth Biorhythms in the Freshwater Pearl Mussel Margaritifera Margaritifera (Bivalvia, Margaritiferidae)
    Knowl. Manag. Aquat. Ecosyst. 2018, 419, 44 Knowledge & © A.A. Zotin et al., Published by EDP Sciences 2018 Management of Aquatic https://doi.org/10.1051/kmae/2018033 Ecosystems www.kmae-journal.org Journal fully supported by Onema RESEARCH PAPER Growth biorhythms in the freshwater pearl mussel Margaritifera margaritifera (Bivalvia, Margaritiferidae). Livojoki river population (Karelia) Alexey A. Zotin1, Svetlana A. Murzina2,* and Evgeny P. Ieshko2 1 Koltsov Institute of Developmental Biology of the Russian Academy of Sciences, 26 Vavilov St., 119334 Moscow, Russia 2 Institute of Biology of the Karelian Research Centre of the Russian Academy of Sciences, 11 Pushkinskaya St., 185910 Petrozavodsk, Karelia Abstract – Individual linear growth rates were studied in freshwater pearl mussels Margaritifera margaritifera from the Livojoki River. Growth deceleration coefficients were shown to vary widely and differ significantly among individuals. The average value of the growth deceleration coefficient for the population is 0.060. The growth of mussels in the Livojoki River is accompanied by two regular biorhythms. These biorhythm periods were roughly constant both through an individual’s ontogeny and among mussels, their average periods were 7.16 and 4.09 years. We discuss the possibility that these biorhythms are of thermodynamic nature. Keywords: Margaritifera / Bivalvia / Karelia / growth / biorhythms Résumé – Bioryhtmes de croissance chez la moule perlière d’eau douce Margaritifera margaritifera (Bivalvia, Margaritiferidae). Population de la rivière Livojoki (Carélie). Les taux de croissance linéaire individuels ont été étudiés chez les moules perlières d’eau douce Margaritifera margaritifera de la rivière Livojoki. Les coefficients de ralentissement de la croissance varient considérablement d’une moule à l’autre.
    [Show full text]
  • Os Nomes Galegos Dos Moluscos
    A Chave Os nomes galegos dos moluscos 2017 Citación recomendada / Recommended citation: A Chave (2017): Nomes galegos dos moluscos recomendados pola Chave. http://www.achave.gal/wp-content/uploads/achave_osnomesgalegosdos_moluscos.pdf 1 Notas introdutorias O que contén este documento Neste documento fornécense denominacións para as especies de moluscos galegos (e) ou europeos, e tamén para algunhas das especies exóticas máis coñecidas (xeralmente no ámbito divulgativo, por causa do seu interese científico ou económico, ou por seren moi comúns noutras áreas xeográficas). En total, achéganse nomes galegos para 534 especies de moluscos. A estrutura En primeiro lugar preséntase unha clasificación taxonómica que considera as clases, ordes, superfamilias e familias de moluscos. Aquí apúntase, de maneira xeral, os nomes dos moluscos que hai en cada familia. A seguir vén o corpo do documento, onde se indica, especie por especie, alén do nome científico, os nomes galegos e ingleses de cada molusco (nalgún caso, tamén, o nome xenérico para un grupo deles). Ao final inclúese unha listaxe de referencias bibliográficas que foron utilizadas para a elaboración do presente documento. Nalgunhas desas referencias recolléronse ou propuxéronse nomes galegos para os moluscos, quer xenéricos quer específicos. Outras referencias achegan nomes para os moluscos noutras linguas, que tamén foron tidos en conta. Alén diso, inclúense algunhas fontes básicas a respecto da metodoloxía e dos criterios terminolóxicos empregados. 2 Tratamento terminolóxico De modo moi resumido, traballouse nas seguintes liñas e cos seguintes criterios: En primeiro lugar, aprofundouse no acervo lingüístico galego. A respecto dos nomes dos moluscos, a lingua galega é riquísima e dispomos dunha chea de nomes, tanto específicos (que designan un único animal) como xenéricos (que designan varios animais parecidos).
    [Show full text]
  • Conservation Officer's Report 2013
    Conservation Officer’s Report 2013 ADVICE & HELP: 1. Roman snails: Numerous assistance requests were dealt with concerning Helix pomatia the Roman snail. These included: Assistance with or confirmation of correct Roman snail identification; Advice on survey options and guidance and help for those engaged in conservation work to obtain Natural England licences (H. pomatia is protected under Schedule 5 of the Wildlife & Countryside Act). Suggestions to explain the sudden deaths of Roman snails including for a North Downs population where mortality was noted as to occurring between dawn and dusk. Various suggestions were made for this unusual observation including one from David Heaver of Natural England who suggested, “I would not discount sciomyzids - the adult flies parasitise adult snails and the larvae develop within either the mantle or body of the snail. When the grown larvae leave the snail to pupate, which the evidence often suggests may be overnight, the snail succumbs and will be found in the morning, the larvae having moved off and pupated in litter”. 2. Identification issues: A number of conservation linked identification issues were undertaken. These included clarification of two incorrect identifications of Pisidium tenuilineatum from different parts of Sussex, confusion arising from separation of Valvata piscinalis and V. macrostoma, and several incidents where help was needed to identify large unionid mussels with certainty. ROMAN SNAILS THREATENED BY DEVELOPMENT PLAN: A long and sometimes acrimonious planning dispute had been running for at least nine years between some residents of Harpenden, Hertfordshire and Harpenden Town Council (HTC). This concerns a relatively small area of former allotments and adjacent Westfield Recreation Ground known both to local residents and the council to support a population of Roman snails Helix pomatia.
    [Show full text]
  • The Effects of Environment on Arctica Islandica Shell Formation and Architecture
    Biogeosciences, 14, 1577–1591, 2017 www.biogeosciences.net/14/1577/2017/ doi:10.5194/bg-14-1577-2017 © Author(s) 2017. CC Attribution 3.0 License. The effects of environment on Arctica islandica shell formation and architecture Stefania Milano1, Gernot Nehrke2, Alan D. Wanamaker Jr.3, Irene Ballesta-Artero4,5, Thomas Brey2, and Bernd R. Schöne1 1Institute of Geosciences, University of Mainz, Joh.-J.-Becherweg 21, 55128 Mainz, Germany 2Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany 3Department of Geological and Atmospheric Sciences, Iowa State University, Ames, Iowa 50011-3212, USA 4Royal Netherlands Institute for Sea Research and Utrecht University, P.O. Box 59, 1790 AB Den Burg, Texel, the Netherlands 5Department of Animal Ecology, VU University Amsterdam, Amsterdam, the Netherlands Correspondence to: Stefania Milano ([email protected]) Received: 27 October 2016 – Discussion started: 7 December 2016 Revised: 1 March 2017 – Accepted: 4 March 2017 – Published: 27 March 2017 Abstract. Mollusks record valuable information in their hard tribution, and (2) scanning electron microscopy (SEM) was parts that reflect ambient environmental conditions. For this used to detect changes in microstructural organization. Our reason, shells can serve as excellent archives to reconstruct results indicate that A. islandica microstructure is not sen- past climate and environmental variability. However, animal sitive to changes in the food source and, likely, shell pig- physiology and biomineralization, which are often poorly un- ment are not altered by diet. However, seawater temperature derstood, can make the decoding of environmental signals had a statistically significant effect on the orientation of the a challenging task.
    [Show full text]
  • Age Influences Resistance to Infestation by Freshwater Pearl Mussel (Margaritifera Margaritifera)Glochidia
    Parasitology Research (2019) 118:1519–1532 https://doi.org/10.1007/s00436-019-06300-2 IMMUNOLOGY AND HOST-PARASITE INTERACTIONS - ORIGINAL PAPER Host (Salmo trutta) age influences resistance to infestation by freshwater pearl mussel (Margaritifera margaritifera)glochidia Janhavi Marwaha1 & Hans Aase2 & Juergen Geist3 & Bernhard C. Stoeckle3 & Ralph Kuehn4,5 & Per Johan Jakobsen1 Received: 30 October 2018 /Accepted: 20 March 2019 /Published online: 1 April 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract The freshwater pearl mussel (Margaritifera margaritifera) is an endangered bivalve with an obligate parasitic stage on salmonids. Host suitability studies have shown that glochidial growth and load vary significantly between host strains as well as among individuals of a suitable strain. Variation in host suitability has been linked to environmental conditions, host age and/or size, genetic composition of the host and parasite, or a combination of these factors. In our study, we wanted to investigate if brown trout (Salmo trutta) displayed an age-dependent response to glochidial infestation. We hypothesised that 1+ naive brown trout hosts tolerate glochidial infestation better than 0+ hosts. In order to test our hypothesis, we infested 0+ and 1+ hatchery reared brown trout with glochidia from closely related mothers and kept them under common garden conditions. This allowed us to observe a pure age dependent host response to infestation, as we eliminated the confounding effect of genotype-specific host interactions. We analysed the interaction between glochidial load and host condition, weight and length, and observed a signif- icant age-dependent relationship. Glochidial load was negatively correlated to host condition in 0+ fish hosts and positively correlated in 1+ hosts.
    [Show full text]
  • The Marine and Brackish Water Mollusca of the State of Mississippi
    Gulf and Caribbean Research Volume 1 Issue 1 January 1961 The Marine and Brackish Water Mollusca of the State of Mississippi Donald R. Moore Gulf Coast Research Laboratory Follow this and additional works at: https://aquila.usm.edu/gcr Recommended Citation Moore, D. R. 1961. The Marine and Brackish Water Mollusca of the State of Mississippi. Gulf Research Reports 1 (1): 1-58. Retrieved from https://aquila.usm.edu/gcr/vol1/iss1/1 DOI: https://doi.org/10.18785/grr.0101.01 This Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf and Caribbean Research by an authorized editor of The Aquila Digital Community. For more information, please contact [email protected]. Gulf Research Reports Volume 1, Number 1 Ocean Springs, Mississippi April, 1961 A JOURNAL DEVOTED PRIMARILY TO PUBLICATION OF THE DATA OF THE MARINE SCIENCES, CHIEFLY OF THE GULF OF MEXICO AND ADJACENT WATERS. GORDON GUNTER, Editor Published by the GULF COAST RESEARCH LABORATORY Ocean Springs, Mississippi SHAUGHNESSY PRINTING CO.. EILOXI, MISS. 0 U c x 41 f 4 21 3 a THE MARINE AND BRACKISH WATER MOLLUSCA of the STATE OF MISSISSIPPI Donald R. Moore GULF COAST RESEARCH LABORATORY and DEPARTMENT OF BIOLOGY, MISSISSIPPI SOUTHERN COLLEGE I -1- TABLE OF CONTENTS Introduction ............................................... Page 3 Historical Account ........................................ Page 3 Procedure of Work ....................................... Page 4 Description of the Mississippi Coast ....................... Page 5 The Physical Environment ................................ Page '7 List of Mississippi Marine and Brackish Water Mollusca . Page 11 Discussion of Species ...................................... Page 17 Supplementary Note .....................................
    [Show full text]
  • 12.2% 122,000 135M Top 1% 154 4,800
    We are IntechOpen, the world’s leading publisher of Open Access books Built by scientists, for scientists 4,800 122,000 135M Open access books available International authors and editors Downloads Our authors are among the 154 TOP 1% 12.2% Countries delivered to most cited scientists Contributors from top 500 universities Selection of our books indexed in the Book Citation Index in Web of Science™ Core Collection (BKCI) Interested in publishing with us? Contact [email protected] Numbers displayed above are based on latest data collected. For more information visit www.intechopen.com Chapter 3 Structure-Function of Serotonin in Bivalve Molluscs Sayyed Mohammad Hadi Alavi, Kazue Nagasawa, Keisuke G. Takahashi and Makoto Osada Additional information is available at the end of the chapter http://dx.doi.org/10.5772/intechopen.69165 Abstract It has been observed that 5-HT excites the heart nerves in hard clam and regulates con- traction and relaxation of the anterior byssus retractor muscle in the blue mussel. It is now known that 5-HT regulates several neurobehavioral systems such as mood, appetite, sleep, learning, and memory. It also plays critical roles in the physiological functions of peripheral organs involved in stress, growth, and reproduction in the animal kingdom. The present study reviews conserved 5-HT biosynthesis and its localization in the ner- vous system, and its physiological contribution to regulate reproduction in bivalves. In the cytosol of neurons, tryptophan hydroxylase catalyzes hydroxylation of l-tryptophan to 5-hydroxytryptophan, which is converted to 5-HT by aromatic l-amino acid decarbox- ylase. A 5-HT transporter and a monoamine oxidase reuptakes and metabolizes 5-HT to control the amount of released 5-HT in the nervous system and peripheral organs.
    [Show full text]
  • Guide to Estuarine and Inshore Bivalves of Virginia
    W&M ScholarWorks Dissertations, Theses, and Masters Projects Theses, Dissertations, & Master Projects 1968 Guide to Estuarine and Inshore Bivalves of Virginia Donna DeMoranville Turgeon College of William and Mary - Virginia Institute of Marine Science Follow this and additional works at: https://scholarworks.wm.edu/etd Part of the Marine Biology Commons, and the Oceanography Commons Recommended Citation Turgeon, Donna DeMoranville, "Guide to Estuarine and Inshore Bivalves of Virginia" (1968). Dissertations, Theses, and Masters Projects. Paper 1539617402. https://dx.doi.org/doi:10.25773/v5-yph4-y570 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]. GUIDE TO ESTUARINE AND INSHORE BIVALVES OF VIRGINIA A Thesis Presented to The Faculty of the School of Marine Science The College of William and Mary in Virginia In Partial Fulfillment Of the Requirements for the Degree of Master of Arts LIBRARY o f the VIRGINIA INSTITUTE Of MARINE. SCIENCE. By Donna DeMoranville Turgeon 1968 APPROVAL SHEET This thesis is submitted in partial fulfillment of the requirements for the degree of Master of Arts jfitw-f. /JJ'/ 4/7/A.J Donna DeMoranville Turgeon Approved, August 1968 Marvin L. Wass, Ph.D. P °tj - D . dvnd.AJlLJ*^' Jay D. Andrews, Ph.D. 'VL d. John L. Wood, Ph.D. William J. Hargi Kenneth L. Webb, Ph.D. ACKNOWLEDGEMENTS The author wishes to express sincere gratitude to her major professor, Dr.
    [Show full text]
  • Phylogeography and Conservation Genetics of Endangered European Margaritiferidae (Bivalvia: Unionoidea)
    Blackwell Science, LtdOxford, UKBIJBiological Journal of the Linnean Society0024-4066The Linnean Society of London, 2003? 2003 78? Original Article A. MACHORDOM ET AL. MARGARITIFERIDAE CONSERVATION GENETICS Biological Journal of the Linnean Society, 2003, 78, 235–252. With 3 figures Phylogeography and conservation genetics of endangered European Margaritiferidae (Bivalvia: Unionoidea) ANNIE MACHORDOM*, RAFAEL ARAUJO, DIRK ERPENBECK† and MARÍA-ÁNGELES RAMOS Museo Nacional de Ciencias Naturales, José Gutiérrez Abascal 2, 28006 Madrid, Spain. Received 26 April 2002; accepted for publication 29 October 2002 Margaritifera margaritifera and M. auricularia are among the most endangered freshwater mussels in the world, and the only species of the genus found in Europe. Our genetic study explores allozymic variability (27 loci) and dif- ferentiation at the mitochondrial sequence level (partial COI and 16S rRNA gene sequences). The Spanish M. auric- ularia population showed genetic parameters of variation that were of the same order as those of other freshwater molluscs (though at the lower end of the range), probably permitting its potential recovery. The difference between this species and M. margaritifera was clearly established (ten diagnostic allozymic loci, Nei = 0.462, and mean nucle- otide divergence around 9.4%). The M. margaritifera populations analysed showed a certain degree of population genetic structure (according to allozyme data) that was not, however, related to a geographical cline. Nevertheless, two mitochondrial lineages (albeit very closely related) were identified: a northern lineage extending from Ireland to the Kola Peninsula including the western Atlantic coast, and a second cluster distributed from Ireland to the Iberian Peninsula. The phylogenetic relationships between these two species and other related taxa were established.
    [Show full text]
  • Freshwater Pearl Mussel (Margaritifera Margaritifera)
    European Community Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora (92/43/EEC) Fourth Report by the United Kingdom under Article 17 on the implementation of the Directive from January 2013 to December 2018 Supporting documentation for the conservation status assessment for the species: S1029 ‐ Freshwater pearl mussel (Margaritifera margaritifera) WALES IMPORTANT NOTE ‐ PLEASE READ • The information in this document is a country‐level contribution to the UK Reporton the conservation status of this species, submitted to the European Commission aspart of the 2019 UK Reporting under Article 17 of the EU Habitats Directive. • The 2019 Article 17 UK Approach document provides details on how this supporting information was used to produce the UK Report. • The UK Report on the conservation status of this species is provided in a separate doc‐ ument. • The reporting fields and options used are aligned to those set out in the European Com‐ mission guidance. • Explanatory notes (where provided) by the country are included at the end. These pro‐ vide an audit trail of relevant supporting information. • Some of the reporting fields have been left blank because either: (i) there was insuffi‐ cient information to complete the field; (ii) completion of the field was not obligatory; (iii) the field was not relevant to this species (section 12 Natura 2000 coverage forAnnex II species) and/or (iv) the field was only relevant at UK‐level (sections 9 Future prospects and 10 Conclusions). • For technical reasons, the country‐level future trends for Range, Population and Habitat for the species are only available in a separate spreadsheet that contains all the country‐ level supporting information.
    [Show full text]
  • Ices Wgitmo Report 2013
    ICES WGITMO REPORT 2013 ICES ADVISORY COMMITTEE ICES CM 2013/ACOM:30 Report of the ICES Working Group on Introduc- tion and Transfers of Marine Organisms (WGITMO) 20 - 22 March 2013 Montreal, Canada International Council for the Exploration of the Sea Conseil International pour l’Exploration de la Mer H. C. Andersens Boulevard 44–46 DK-1553 Copenhagen V Denmark Telephone (+45) 33 38 67 00 Telefax (+45) 33 93 42 15 www.ices.dk [email protected] Recommended format for purposes of citation: ICES. 2013. Report of the ICES Working Group on Introduction and Transfers of Ma- rine Organisms (WGITMO), 20 - 22 March 2013, Montreal, Canada. ICES CM 2013/ACOM:30. 149 pp. For permission to reproduce material from this publication, please apply to the Gen- eral Secretary. The document is a report of an Expert Group under the auspices of the International Council for the Exploration of the Sea and does not necessarily represent the views of the Council. © 2013 International Council for the Exploration of the Sea ICES WGITMO REPORT 2013 i Contents Executive summary ................................................................................................................ 1 1 Opening of the meeting ................................................................................................ 2 2 Adoption of the agenda ................................................................................................ 2 3 WGITMO Terms of Reference .................................................................................... 2 4 Progress in relation
    [Show full text]
  • CHARACTERISTICS of THREE WESTERN PEARLSHELL (MARGARITIFERA FALCATA) POPULATIONS in the CHEHALIS RIVER BASIN, WASHINGTON STATE By
    CHARACTERISTICS OF THREE WESTERN PEARLSHELL (MARGARITIFERA FALCATA) POPULATIONS IN THE CHEHALIS RIVER BASIN, WASHINGTON STATE by Frithiof Teal Waterstrat A Thesis Submitted in partial fulfillment of the requirements for the degree Master of Environmental Studies The Evergreen State College August 2013 © 2013 by Frithiof T. Waterstrat. All rights reserved. This Thesis for the Master of Environmental Studies Degree by Frithiof Teal Waterstrat has been approved for The Evergreen State College by ________________________ Dr. Carri J. LeRoy Member of the Faculty ________________________ Date ABSTRACT CHARACTERISTICS OF THREE WESTERN PEARLSHELL (MARGARITIFERA FALCATA) POPULATIONS IN THE CHEHALIS RIVER BASIN, WASHINGTON STATE Freshwater unionoid mussels are the most imperiled family of freshwater organisms in North America. In Washington State, documentation of mussel populations, abundances, and investigations of environmental conditions influencing their morphology are limited to a few studies. Here, I describe three populations of the western pearlshell (Margaritifera falcata) in the lower Chehalis River basin occurring along an ecological and physical gradient from a headwater stream to a major regional river. Quantitative analysis revealed a trend of increasing shell size as well as shell weight to length ratio along this gradient, but I found no difference in external shell measurement ratios as watershed area increased. Environmental conditions that coincide with an increase in western shell size and proportional shell weight are discussed within. Additionally, information regarding mussel distributions was gleaned from opportunistic interviews with individuals encountered during this research as well as from field notes during surveys for native fish populations. These were then compared to existing records of mussel distributions in Washington. This information led to the reporting of 15 specific mussel localities in this thesis not yet documented in existing databases.
    [Show full text]