DOCSLIB.ORG

What Makes a Ferox? the Drivers and Consequences of Alternative Life History Strategies in S

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Hughes, Martin Robert (2017) What makes a ferox? The drivers and consequences of alternative life history strategies in S. trutta. PhD thesis. https://theses.gla.ac.uk/8280/ Copyright and moral rights for this work are retained by the author A copy can be downloaded for personal non-commercial research or study, without prior permission or charge This work cannot be reproduced or quoted extensively from without first obtaining permission in writing from the author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given Enlighten: Theses https://theses.gla.ac.uk/ [email protected] WHAT MAKES A FEROX? THE DRIVERS & CONSEQUENCES OF ALTERNATIVE LIFE HISTORY STRATEGIES IN S. trutta MARTIN ROBERT HUGHES BSC, UNIVERSITY OF GLASGOW, 2012 SUBMITTED IN FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY SCOTTISH CENTRE FOR ECOLOGY AND THE NATURAL ENVIRONMENT, INSTITUTE OF BIODIVERSITY, ANIMAL HEALTH AND COMPARATIVE MEDICINE, COLLEGE OF MEDICAL AND LIFE SCIENCES, UNIVERSITY OF GLASGOW January 2017 © MARTIN ROBERT HUGHES 2017 ABSTRACT Understanding the mechanisms involved in producing and maintaining variation in phenotype, behaviour and life history traits within a single species, is of fundamental importance to evolutionary biology. Such intraspecific variation is well observed in organisms inhabiting depauperate environments, exploiting uncontested trophic niches. Classic examples can be found in island communities such as Darwin’s Finches of the Galapagos Islands and the Anolis lizards of the Caribbean, where organisms derived from a single invading ancestor rapidly diversified into numerous ecologically distinct niches, forming distinct and often reproductively isolated populations. Such adaptive radiations are considered an essential prerequisite to species formation and is often referred to as ecological speciation. Freshwater lakes share characteristics similar to islands that enable ecological speciation to occur rapidly. The rapid proliferation of African cichlids species in the African Great lakes is perhaps the best example of ecological speciation found on Earth today. Thousands of species of African cichlids have been described within Lakes Malawi, Tanganyika and Victoria each adapted, often morphologically, to a particular ecological niche. Fish species inhabiting post-glacial lakes of the Northern hemisphere represent model organisms to study the early mechanism of ecological speciation. Species such as Arctic charr and Three-spine sticklebacks have diverged across ecological axes within a single lake in numerous systems. As post-glacial lakes were inaccessible to ancestral fish until the last glacial retreat, (approximately > 15 000 years ago) the observed divergences have occurred in an extremely short amount of time. Brown trout Salmo trutta can exhibit multiple life histories within a single lacustrine system, including benthic, pelagic and piscivorous forms. The piscivorous form, known colloquially as ferox trout, are a relatively rare, understudied form of the S. trutta species complex. Interestingly ferox trout not only exhibit discrete morphology and foraging behaviour they also have higher growth potential, delayed maturation and extended longevity compared with sympatric S. trutta. Indeed, ferox trout represent a genetically distinct ancestral lineage in some locations where they occur, however the ecological, physiological and behavioural mechanisms driving the production of ferox trout populations has yet to be investigated. Thus, the thesis presented here tests the importance of different drivers in ferox trout production to increase our understanding of species formation and ecological speciation. Furthermore, I also investigated the within lake movements (home range, core range, speed) of benthic and pelagic S. trutta occurring in sympatry to determine 2 differential habitat use. In the General Introduction (chapter 1) I extensively review the available literature on adaptive radiations and ecological speciation with a particular emphasis on fish in post-glacial lakes. I discuss the history of ferox trout to contextualise the current thinking and to highlight knowledge gaps within the research. To investigate the ecological drivers of ferox trout populations, fine scale environmental characteristics associated with known ferox trout populations were investigated. I found large, deep lakes with populations of S. alpinus were highly correlated with ferox trout populations. I found 192 lakes in Scotland have evidence of supporting ferox trout and 366 lakes in Scotland could theoretically support ferox trout based on lake area alone (chapter 2). The alternative growth strategies and life spans exhibited by ferox trout and sympatric benthivorous brown trout (benthivorous trout hereafter), were examined by comparing the growth trajectories and age structures of three sympatric populations (Loch Rannoch, Loch Awe and Loch na Sealga). In Loch Rannoch, the ferox population adhered to the conventional model of growth proposed for ferox trout, i.e. relatively slow growth followed by an acceleration of growth after a switch to piscivory, however the two other populations did not conform to this model of growth. In Loch Awe, ferox trout grew much faster than benthivorous trout, including early ontogeny, however in Loch na Sealga there were no measurable differences in growth. Interestingly, all ferox trout populations were older than benthivorous trout. These results demonstrate that there are multiple ontogenetic growth pathways to achieving piscivory in S. trutta and that the adoption of a piscivorous diet may be a major factor contributing to extension of life span in S. trutta (chapter 3). Physiological, morphological and behavioural drivers were investigated by rearing full-sibling families of sympatric ferox trout and benthivorous brown trout from eggs in the laboratory, under common garden conditions. I found offspring from ferox trout parents had higher survival rates, larger yolk sacs and decreased levels of mesenteric fat, compared with offspring from sympatric benthivorous trout. Offspring of ferox trout and benthivorous trout also had distinct head shape morphology, which converged over time under common garden conditions (chapter 4). Offspring from ferox trout were more dominant than size-matched offspring from sympatric benthivorous trout, by examining food acquisition ability, spatial position, flank colour index and aggressive interactions within a semi-natural stream system (chapter 5). Lastly, the within lake movement of sympatric benthic and pelagic S. trutta was investigated by acoustic telemetry. Acoustic tags were surgically implanted into S. trutta exhibiting distinct head morphologies associated with trophic position in an oligotrophic 3 post-glacial lake. Tagged S. trutta were tracked over a three-month period (July-September). No differences in home range or core area size (km2) between benthic and pelagic S. trutta were identified. However, both forms demonstrated clear diel cycles in movement and responded similarly to temporal change. There was extensive overlap in core use of the lake, however pelagic trout were found over deeper waters more often than benthic trout (chapter 6). In the general discussion (chapter 7), I summarise the results of these studies and discuss the evolutionary, conservation and economic importance of such research. I also discuss the limitations of this research and the potential future areas of study. 4 “It seems to me that the natural world is the greatest source of excitement; the greatest source of visual beauty; the greatest source of intellectual interest. It is the greatest source of so much in life that makes life worth living.” SIR DAVID ATTENBOROUGH “When you want to succeed as bad as you want to breathe, then you will be successful.” ERIC THOMAS 5 CONTENTS CHAPTER 1. GENERAL INTRODUCTION. 1.1. HISTORY OF EVOLUTIONARY THEORY ........................................... 20 1.2. ADAPTIVE RADIATION .............................................................. 21 1.3. ECOLOGICAL OPPORTUNITY ....................................................... 22 1.3.1. NEW RESOURCES ................................................................. 22 1.3.2. MASS EXTINCTION ................................................................ 23 1.3.3. EVOLUTION OF NOVEL TRAITS ................................................. 23 1.3.4. COLONISING NEW HABITAT ..................................................... 23 1.4. PHENOTYPIC PLASTICITY ......................................................... 24 1.5. TROPHIC NICHE SPECIALISATION ................................................. 25 1.6. REPLICATED ADAPTIVE RADIATION .............................................. 26 1.7. POST GLACIAL LAKES ............................................................... 28 1.7.1. THREE-SPINE STICKLEBACKS ................................................... 28 1.7.2. RAINBOW SMELT ................................................................. 29 1.7.3. LAKE WHITEFISH ................................................................. 30 1.7.4. ATLANTIC SALMON ............................................................... 31 1.7.5. ARCTIC CHARR ................................................................... 32 1.7.6. BROWN TROUT ..................................................................
Recommended publications
  • Bonneville Cutthroat Trout (Oncorhynchus Clarki Utah) Bonneville Cutthroat Trout Is One of Three Cutthroat Trout Subspecies Native to Utah

    Bonneville Cutthroat Trout (Oncorhynchus Clarki Utah) Bonneville Cutthroat Trout Is One of Three Cutthroat Trout Subspecies Native to Utah

    FISH Bonneville Cutthroat Trout (Oncorhynchus clarki utah) Bonneville cutthroat trout is one of three cutthroat trout subspecies native to Utah. Bonneville cutthroat trout historically occurred in the Pleistocene Lake Bonneville basin, which included portions of Idaho, Nevada, Utah, and Wyoming (Kershner 1995). The desiccation of Lake Bonneville into the smaller Great Salt Lake and fragmentation of other stream and lake habitats may have led to three slightly differentiated groups of Bonneville cutthroat trout. These groups are found in the Bonneville basin proper, the Bear River drainage, and the Snake Valley (Behnke 1992). There are five known populations of pure strain Bonneville cutthroat trout on the Fishlake National Forest inhabiting approximately 38 miles of stream habitat. There are several recently reintroduced populations, and several small potential remnant populations. Habitat for the Bonneville cutthroat trout is widely distributed and variable. It ranges from high elevation (3,500 m mean sea level) streams with coniferous and deciduous riparian trees to low elevation (1,000 m mean sea level) streams in sage-steppe grasslands containing herbaceous riparian zones. As such, Bonneville cutthroat trout have adapted to a broad spectrum of habitat conditions throughout their range (Kershner 1995). Sexual maturity is typically reached during the second year for males and the third year for females (May et al. 1978). Both the age at maturity and the annual timing of spawning vary geographically with elevation, temperature, and life history strategy. Lake resident trout may begin spawning at two years of age and usually continue throughout their lives, while adfluvial individuals may not spawn for several years.
  • The Native Trouts of the Genus Salmo of Western North America

    The Native Trouts of the Genus Salmo of Western North America

    CItiEt'SW XHPYTD: RSOTLAITYWUAS 4 Monograph of ha, TEMPI, AZ The Native Trouts of the Genus Salmo Of Western North America Robert J. Behnke "9! August 1979 z 141, ' 4,W \ " • ,1■\t 1,es. • . • • This_report was funded by USDA, Forest Service Fish and Wildlife Service , Bureau of Land Management FORE WARD This monograph was prepared by Dr. Robert J. Behnke under contract funded by the U.S. Fish and Wildlife Service, the Bureau of Land Management, and the U.S. Forest Service. Region 2 of the Forest Service was assigned the lead in coordinating this effort for the Forest Service. Each agency assumed the responsibility for reproducing and distributing the monograph according to their needs. Appreciation is extended to the Bureau of Land Management, Denver Service Center, for assistance in publication. Mr. Richard Moore, Region 2, served as Forest Service Coordinator. Inquiries about this publication should be directed to the Regional Forester, 11177 West 8th Avenue, P.O. Box 25127, Lakewood, Colorado 80225. Rocky Mountain Region September, 1980 Inquiries about this publication should be directed to the Regional Forester, 11177 West 8th Avenue, P.O. Box 25127, Lakewood, Colorado 80225. it TABLE OF CONTENTS Page Preface ..................................................................................................................................................................... Introduction ..................................................................................................................................................................
  • Oncorhynchus Mykiss)

    Oncorhynchus Mykiss)

    Growth Genes Are Implicated in The Evolutionary Divergence of Sympatric Piscivorous and Insectivorous Rainbow Trout (Oncorhynchus Mykiss) Jared A. Grummer ( [email protected] ) University of British Columbia Michael Whitlock University of British Columbia Patricia Schulte University of British Columbia Eric Taylor University of British Columbia Research Article Keywords: genome scan, small-effect loci, FST, GO analysis, rainbow trout, ecotype Posted Date: February 5th, 2021 DOI: https://doi.org/10.21203/rs.3.rs-157772/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Version of Record: A version of this preprint was published at BMC Ecology and Evolution on April 22nd, 2021. See the published version at https://doi.org/10.1186/s12862-021-01795-9. RH: GENOMIC DIVERGENCE OF SYMPATRIC TROUT ECOTYPES Growth genes are implicated in the evolutionary divergence of sympatric piscivorous and insectivorous rainbow trout (Oncorhynchus mykiss) Jared A. Grummer1, Michael Whitlock1, Patricia M. Schulte1, and Eric B. Taylor1,2 1Department of Zoology and Biodiversity Research Centre, University of British Columbia, 6270 University Blvd., Vancouver, BC V6T 1Z4, Canada 2Beaty Biodiversity Museum, University of British Columbia, 6270 University Blvd., Vancouver, BC V6T 1Z4, Canada Corresponding author: Jared A. Grummer; E-mail: [email protected] 1 1 Abstract.— 2 Background: Identifying ecologically significant phenotypic traits and the genomic 3 mechanisms that underly them are crucial steps in understanding the traits associated with 4 population divergence. We used genome-wide data to identify genomic regions associated 5 with a key trait that distinguishes two ecotypes of rainbow trout (Oncorhynchus mykiss)– 6 insectivores and piscivores – that coexist in Kootenay Lake, southeastern British Columbia, 7 for the non-breeding portion of the year.
  • History of Lahontan Cutthroat Trout in Spring Creek, Utah

    History of Lahontan Cutthroat Trout in Spring Creek, Utah

    Spring Creek Population History of the Pyramid Lake Rediscovery (Again) Unfortunately, given its small size, the trout Lahontan Cutthroat population at Spring Creek has a very low In October 2009, a team from Weber State probability of survival. It lacks the numbers The Lahontan cutthroat trout, Oncorhynchus University in conjunction with personnel and space necessary to maintain sufficient clarkii henshawi, is native to the Lahontan Basin from the DWR identified several specimens genetic diversity. It is believed that for a on the border between California and Nevada. believed to be of a pure or hybrid strain of mountain stream cutthroat population to For thousands of years it thrived and played the Pyramid Lake Lahontan cutthroat trout survive it must have a minimum of 3.3 km an important economic and cultural role in Spring Creek in Uintah, Utah. Using of habitat and an abundance in the area of among the Native American tribes of the electrofishers and dip nets, a 600 m stretch 0.3 fish per meter.3 Based on our region. The largest strain of this fish of the stream was sampled. A maximum observations, the Spring Creek population originated in Pyramid Lake, in western of 16 different individuals was collected in A Unique Environment has a maximum abundance of 0.1 fish/m Nevada and has reached recorded weights of two sampling trips. The fish appeared to Spring Creek’s unique vegetation and only 200 m of habitat. However, against up to 41 pounds, making it the largest “The Fish that Won’t Die” be restricted to a 200 m stretch.
  • Species Fact Sheet Coastal Cutthroat Trout Oncorhynchus Clarkii

    Species Fact Sheet Coastal Cutthroat Trout Oncorhynchus Clarkii

    Species Fact Sheet Coastal Cutthroat Trout Oncorhynchus clarkii STATUS: SPECIES OF The Southwestern Washington/Lower Columbia CONCERN River Distinct Population Southwestern Segment of Coastal cutthroat Washington/Lower trout potentially occurs in these Washington counties: Thurston, Columbia River Distinct Lewis, Yakima, Mason, Pacific, Population Segment Grays Harbor, Wahkiakum, Cowlitz, Clark, Skaminia, Klickitat, (Map may reflect historical as well as recent sightings) In 1999, the southwestern Washington/lower Columbia River Distinct Population Segment of coastal cutthroat trout, Oncorhynchus clarkii clarkii, was listed as threatened by National Marine Fisheries Service and the U.S. Fish and Wildlife Service FR 64(64): 16397-414. Subsequently, the Fish and Wildlife Service assumed sole regulatory jurisdiction. Based on changes in forest management regulation, the latest information indicating better than expected total populations in a large portion of the area, and an improved understanding of the ability of freshwater forms to produce anadromous progeny, the Fish and Wildlife Service withdrew the listing proposal in 2002. Current and Historical Status This Distinct Population Segment (DPS) includes populations in the Columbia River and its tributaries downstream from the Klickitat River in Washington and Fifteenmile Creek in Oregon to the Columbia River estuary; and the Willamette River and its tributaries downstream from Willamette Falls, to its confluence with the Columbia River, as well as in tributaries of Gray's Harbor and Willapa Bay. The southwestern Washington-lower Columbia River region historically supported highly productive coastal cutthroat trout populations. Coastal cutthroat trout are well distributed in most river basins in this geographic region, although probably in lower numbers relative to historical population sizes.
  • Coyote Lake Lahontan Cutthroat Trout

    Coyote Lake Lahontan Cutthroat Trout

    Oregon Native Fish Status Report – Volume II Coyote Lake Lahontan Cutthroat Trout Existing Populations Lahontan cutthroat trout populations in the Coyote Lakes basin are remnant of a larger population inhabiting pluvial Lake Lahontan during the Pleistocene era. Hydrologic access routes of founding cutthroat trout from Lake Lahontan basin into the Coyote Lakes basin have yet to be described (Coffin and Cowan 1995). The Coyote Lake Lahontan Cutthroat Trout SMU is comprised of five populations (Table 1). All populations express a resident life history strategy; however large individuals in the Willow and Whitehorse Complex populations suggest a migratory component may exist. Table 1. Populations, existence status, and life history of the Coyote Lake Lahontan Cutthroat Trout SMU. Exist Population Description Life History Yes Willow Willow Creek and tributaries. Resident / Migratory Yes Whitehorse Complex Whitehorse and Little Whitehorse Creeks, and Resident / Migratory tributaries. Yes Doolittle Doolittle Creek above barrier. Resident Yes Cottonwood Cottonwood Creek above barrier. Resident Yes Antelope Antelope Creek. Resident Lahontan cutthroat trout from Willow and Whitehorse creeks were transplanted into Cottonwood Creek in 1971 and 1980, and into Antelope Creek in 1972 (Hanson et al. 1993). Whether Lahontan cutthroat trout were present in these creeks prior to stocking activities is disputed (Behnke 1992, Hanson et al. 1993, Coffin and Cowan 1995, K. Jones, ODFW Research Biologist, Corvallis, OR personal communication). For the purpose of this review these populations are considered native. Lahontan cutthroat trout were also transplanted into Fifteenmile Creek above a natural barrier (Hanson et al. 1993), but they did not establish a self- sustaining population (ODFW Aquatic Inventory Project, unpublished data).
  • Identification and Modelling of a Representative Vulnerable Fish Species for Pesticide Risk Assessment in Europe

    Identification and Modelling of a Representative Vulnerable Fish Species for Pesticide Risk Assessment in Europe

    Identification and Modelling of a Representative Vulnerable Fish Species for Pesticide Risk Assessment in Europe Von der Fakultät für Mathematik, Informatik und Naturwissenschaften der RWTH Aachen University zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften genehmigte Dissertation vorgelegt von Lara Ibrahim, M.Sc. aus Mazeraat Assaf, Libanon Berichter: Universitätsprofessor Dr. Andreas Schäffer Prof. Dr. Christoph Schäfers Tag der mündlichen Prüfung: 30. Juli 2015 Diese Dissertation ist auf den Internetseiten der Universitätsbibliothek online verfügbar Erklärung Ich versichere, dass ich diese Doktorarbeit selbständig und nur unter Verwendung der angegebenen Hilfsmittel angefertigt habe. Weiterhin versichere ich, die aus benutzten Quellen wörtlich oder inhaltlich entnommenen Stellen als solche kenntlich gemacht zu haben. Lara Ibrahim Aachen, am 18 März 2015 Zusammenfassung Die Zulassung von Pflanzenschutzmitteln in der Europäischen Gemeinschaft verlangt unter anderem eine Abschätzung des Risikos für Organismen in der Umwelt, die nicht Ziel der Anwendung sind. Unvertretbare Auswirkungen auf den Naturhalt sollen vermieden werden. Die ökologische Risikoanalyse stellt die dafür benötigten Informationen durch eine Abschätzung der Exposition der Organismen und der sich daraus ergebenden Effekte bereit. Die Effektabschätzung beruht dabei hauptsächlich auf standardisierten ökotoxikologischen Tests im Labor mit wenigen, oft nicht einheimischen Stellvertreterarten. In diesen Tests werden z. B. Effekte auf das Überleben, das Wachstum und/oder die Reproduktion von Fischen bei verschiedenen Konzentrationen der Testsubstanz gemessen und Endpunkte wie die LC50 (Lethal Concentrations for 50%) oder eine NOEC (No Observed Effect Concentration, z. B. für Wachstum oder Reproduktionsparameter) abgeleitet. Für Fische und Wirbeltiere im Allgemeinen beziehen sich die spezifischen Schutzziele auf das Überleben von Individuen und die Abundanz und Biomasse von Populationen.
  • Feeding Selectivity of Brown Trout (Salmo Trutta) in Loch Ness, Scotland Stephen Thackeray, Jonathan Grey and Roger Jones (S

    Feeding Selectivity of Brown Trout (Salmo Trutta) in Loch Ness, Scotland Stephen Thackeray, Jonathan Grey and Roger Jones (S

    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Aquatic Commons FEEDING SELECTIVITY OF BROWN TROUT 47 FEEDING SELECTIVITY OF BROWN TROUT (SALMO TRUTTA) IN LOCH NESS, SCOTLAND STEPHEN THACKERAY, JONATHAN GREY AND ROGER JONES (S. J. Thackeray, Dr J. Grey and Dr R. I. Jones, Department of Biological Sciences, IENS, Lancaster University, Lancaster LAI 4YQ, England.) [E-mail: s.j. thackeray @ lancaster. ac. uk] Introduction Loch Ness (Fig. 1) lies in the Great Glen, a glacially-deepened rift which was originally tectonic in origin. Hence the loch has a very regular trench-like morphometry, with steeply shelving sides sloping down to a flat bed. This produces a restricted littoral zone, where powerful wave action on the steep, rocky shores permits growth of few macrophytes (Burgis & Morris 1987). The loch has the greatest mean depth of any lake in Britain and Ireland (ca. 132 metres) and comprises two basins, the north reaching a maximum depth of 227 metres and the south a maximum of 221 metres (Young & Shine 1993). Consequently, Loch Ness contains the largest volume of water for any lake in the British Isles (74.52 m3 x 108). The loch drains eastwards via the River Ness and has been connected to the west coast by the Caledonian canal since 1822. It is oligotrophic and the water is extensively stained with peat (Burgis & Morris 1987), so that light attenuates rapidly in the Loch Ness water column. Martin & Shine (1988) found that most of the pelagic fish in Loch Ness inhabited the top 30 metres of the water column, with Arctic charr Salvelinus alpinus dominating much of this stratum.
  • Market-Sized Cutthroat Trout Technical Report Western Regional Aquaculture Center

    Market-Sized Cutthroat Trout Technical Report Western Regional Aquaculture Center

    Feeds for Production of Market-sized Cutthroat Trout Technical Report WESTERN REGIONAL AQUACULTURE CENTER Gary Fornshell, University of Idaho Christopher Myrick, Colorado State University Madison Powell, University of Idaho Wendy Sealey, United States Fish and Wildlife Service United States Department of Agriculture National Institute of Food and Agriculture 1 PROJECT PARTICIPANTS Christopher Myrick, Colorado State University Cheyenne Owens, Colorado State University Biswamitra Patro, University of Idaho Madison Powell, University of Idaho Pat Blaufuss, University of Idaho Tracy Kennedy, University of Idaho Wendy Sealey, United States Fish and Wildlife Service Brian Ham, United States Fish and Wildlife Service Gary Fornshell, University of Idaho Jeremy Liley, Liley Fisheries, Inc. David Brock, Rangen, Inc. Jackie Zimmerman, Skretting USA Rick Barrows, Aquatic Feed Technologies, LLC Photo credits: Cover: Gary Fornshell Above: iStock.com/KaraGrubis 2 Table of Contents Introduction: Why Consider Cutthroat Trout? 1 Snake River Cutthroat Trout—A Culturable Cutthroat 2 Is Raising Fish for the Recreational Market Worthwhile? 3 Overcoming Challenges to Raising Cutthroat Trout 3 Fish Nutrition 101—A Primer on Feed Formulation 3 Feed Pellet Texture Matters 5 Cutthroat Trout Growth—Does It Match Rainbow Trout? 5 Thermal Growth Coefficient 5 Comparing Rainbow and Cutthroat Trout Performance 6 Suggested Readings 10 Acknowledgments 11 Figures 1. Snake River cutthroat trout. 1 2. Map showing the distribution of extant cutthroat trout 2 subspecies in the western United States. 3. Juvenile Snake River cutthroat trout ready for stocking. 3 4. Classic bell-shaped growth-temperature curve. 6 5. Sigmoid growth curve. Based on Fish Hatchery Management, Second Edition, Gary Wedemeyer, editor 7 6.
  • Spatial Variation in Spawning Habitat of Cutthroat Trout in a Sediment

    Spatial Variation in Spawning Habitat of Cutthroat Trout in a Sediment

    Transactions of the American Fisheries Society 125:768-779. 1996 © Copyright by the American Fisheries Society 1996 Spatial Variatio Spawninn i g Habita f Cutthroato t Troua n ti Sediment-Rich Stream Basin JAMES P. MAGEE' AND THOMAS E. McMAHON2 Biology Department, FishWildlifeand Program Montana State University, Bozeman, Montana 59717,USA RUSSELL E THUROW U.S. Forest Service, Intermountain Research Station 316 East Myrtle Street. Boise, Idaho 83702,USA Abstract.—We examined distributio habitad nan t characteristic f spawnino s g site f cutthroaso t trout Oncorhynchus clarki t varioua s spatial scale asseso st s effect f sedimentatioso n withi nlarga e basin in Montana. Redd density varied widely across the basin; nearly all (99%) of the 362 redds observed occurred in two high-elevation headwater tributaries. Redd density at the reach scale s positivelwa y correlate 0.001= 0.72= 2 P ,d(r ) with abundanc f spawnino e g gravels. Other habitat variables, such as gradient, width, depth, embeddedness, bank stability, and percent riffle, were not significantly correlated to redd density. Taylor Fork redds contained some of the highest proportions of fine sediments (<6.35 mm, mean = 41.6%; <0.85 mm, 17.9%) observed in egg pocket salmonif so d Rocke reddth n si y Mountain region. Cache Creek highl,a y disturbed subbasin, d significantlha y greater proportion f fino s e sediments smaller tha reddn i n 0.8m s m 5tha e nth undisturbed Wapiti Creek subbasin. High fine-sediment level vero reddestimaten t w i s d ylo sle d embryo survival (mean, 8.5%) t sedimentatiobu , t appeano limid o t r di n t recruitment r datOu a.
  • Westslope Cutthroat Trout

    Westslope Cutthroat Trout

    Oregon Native Fish Status Report – Volume II Westslope Cutthroat Trout Existing Populations Oregon populations of westslope cutthroat trout are disjunct from their greater contiguous distribution in the Upper Missouri and Columbia basins of Montana and Idaho (Behnke 1992). The Westslope Cutthroat Trout SMU is comprised of 17 populations in the upper mainstem John Day River basin (Table 1). Populations were identified according to those defined in the interagency westslope cutthroat trout range-wide assessment (Shepard et al. 2003). The interagency assessment identified westslope cutthroat trout in Laycock Creek and the Upper John Day Complex as a single population. This review considers trout in Laycock Creek as a separate population from the Upper John Day Complex due to the significant distance between the two creeks. Most populations express a resident life history strategy, although, migratory forms exist in the Upper John Day Complex and possibly in the Canyon Complex (Hemmingsen 1999a, Shepard et al. 2003). Table 1. Populations, existence status, and life history of the John Day Westslope Cutthroat Trout SMU. Exist Population Description Life History Yes Upper John Day Includes upper mainstem river and tributaries. Resident / Migratory Complex Yes Strawberry Strawberry, Slide, and Squaw Creeks. Resident Yes Dixie Dixie and Standard Creeks. Resident Yes Indian Indian, Little Indian, and Overholt Creeks. Resident Yes Bear Bear Creek. Resident Yes Pine Pine Creek. Resident Yes Dog Dog Creek. Resident Yes Little Pine Little Pine Creek. Resident Yes Canyon Complex Includes Berry, Crazy, and Canyon creeks and Resident / migratory tributaries. Yes Laycock Laycock Creek. Yes Ingle Ingle Creek. Resident Yes Beech Upper Beech, Bear, Cottonwood, and Lake creeks.
  • The Abundance of Large, Piscivorous Ferox Trout (Salmo Trutta) in Loch Rannoch, Scotland

    The Abundance of Large, Piscivorous Ferox Trout (Salmo Trutta) in Loch Rannoch, Scotland

    The abundance of large, piscivorous Ferox Trout (Salmo trutta) in Loch Rannoch, Scotland Alastair Thorne1, Alisdair I. MacDonald1 and Joseph L. Thorley2 1 Freshwater Laboratory, Marine Scotland, Pitlochry, Scotland 2 Poisson Consulting, Nelson, British Columbia, Canada ABSTRACT Background. Ferox Trout are large, long-lived piscivorous Brown Trout (Salmo trutta). Due to their exceptionally large size, Ferox Trout are highly sought after by anglers while their life-history strategy, which includes delayed maturation, multiphasic growth and extended longevity, is of interest to ecological and evolutionary modelers. However, despite their recreational and theoretical importance, little is known about the typical abundance of Ferox Trout. Methods. To rectify this situation a 16 year angling-based mark-recapture study was conducted on Loch Rannoch, which at 19 km2 is one of the largest lakes in the United Kingdom. Results. A hierarchical Bayesian Jolly-Seber analysis of the data suggest that if individual differences in catchability are negligible the population of Ferox Trout in Loch Rannoch in 2009 was approximately 71 fish. The results also suggest that a single, often unaccompanied, highly-experienced angler was able to catch roughly 8% of the available fish on an annual basis. Discussion. It is recommended that anglers adopt a precautionary approach and release all trout with a fork length ≥400 mm caught by trolling in Loch Rannoch. There is an urgent need to assess the status of Ferox Trout in other lakes. Subjects Aquaculture, Fisheries and Fish Science, Conservation Biology, Ecology, Statistics Submitted 11 May 2016 Accepted 3 October 2016 Keywords Survival, Hierarchical, Bayesian, Exploitation, Jolly-Seber, Abundance, Ferox Trout, Published 1 November 2016 Brown Trout, Piscivorous Corresponding author Joseph L.