DOCSLIB.ORG

Direct and Indirect Effects of a Trematode Parasite on the Endemic Freshwater Fish Galaxias Anomalus

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Direct and Indirect Effects of a Trematode Parasite on the Endemic Freshwater Fish Galaxias Anomalus Direct and indirect effects of a trematode parasite on the endemic freshwater fish Galaxias anomalus Harriet Thomas A thesis submitted for the degree of Master of Science Zoology University of Otago Dunedin, New Zealand September 2013 Dedication For my Father From a young age you inspired the scientist within me, I am forever grateful for your unconditional support and belief in me Abstract Abstract Fish have critical periods during early life where mortality is extremely high. There are a multitude of factors which can influence mortality, however, parasitism is often overlooked as a causal factor of mortality during this period. Understanding the extent to which biotic and abiotic factors, such as parasites, can influence fish survival, is paramount for effective management of threatened species. The purpose of this study was to investigate the effects of a trematode parasite, Telogaster opisthorchis (a parasite known to cause malformations in young fish), on the critical larval stage of its second intermediate fish host Galaxias anomalus, a small, endemic, freshwater fish vulnerable to extinction. The influence of T. opisthorchis on the condition, size, and survival of G. anomalus fish was tested by experimentally infecting larval fish of different ages with different doses under standard conditions. Additionally, the likelihood that parasites cause malformations and their influence on the swimming ability of their hosts were also investigated. Swimming tests were carried out using a unidirectional propeller-driven flume where individual fish swimming ability was monitored over a fixed period. Results demonstrate that T. opisthorchis can affect G. anomalus survival directly via reduced condition, and indirectly via malformations and lowered swimming ability. However there was no effect of parasitism on condition or size, nor was there any effect of infection level on the presence of skeletal malformations, the reasons for which are discussed in the text. The effect of parasitism in early life stages of fish influences survival, and in wild populations, may be exacerbated by additional stressors, with consequences at both the population and community level. iii Acknowledgements Acknowledgements Firstly, I am most grateful for the opportunity to work under the supervision of Robert Poulin. Thank you for the opportunities, and graciously putting up with me for so long. Your door was always open, and I am very appreciative of your continual encouragement, and helping me to keep my chin up when planned experiments turned to custard! I was fortunate enough to be out in the field with Dave Kelly when we first came across some kinky looking fish and decided to check it out further. If it wasn’t for our discoveries that day, this research would never have been undertaken. Thanks for all the fun times out in the field and your help and enthusiasm in planning my initial experiment. To the Zoology Department support staff, particularly Matthew Downs, Ken Miller, Kim Garrett, Nicky McHugh, Wendy Shanks, and Ronda Peacock; the Zoology department would be at a loss without you. I particularly want to thank Murray McKenzie for being a creative handyman genius, your flume alterations saved my experiment! A big thank you goes to the Evolutionary and Ecological Parasitology lab, particularly Kristin Herrmann, Isa Blasco-Costa and Bronwyn Preswell for your help with species identification and company in the lab. I am also indebted to Catriona Hurd and Chris Cornwall of the Botany department for allowing me to borrow their flume and helping me to set it up. To all those who helped me in the field, or gave me feedback on earlier drafts who I have not already acknowledged; Todd Beaumont, Abbey Reith, Charles Ellen, Scott Triplow, Lloyd Thomas, and Matthew Wylie (who also generously looked after my fish while I was away). A special thank you goes to Erin Forbes and Craig Preston, who not only helped with fieldwork, but without our coffee, quiz and crossword breaks, I don’t know how I would have survived the day! iv Acknowledgements I also wish to thank NIWA for presenting me with a much needed break from study. While spending time not having to think about my thesis, I was able to learn a huge amount and gain a better perspective and appreciation of my own research. Lastly, I owe a huge thanks to my parents, Briar and Lloyd. Thank you for putting up with me as a student for so long. I am forever grateful for your endless support. v Table of contents Table of contents Abstract ......................................................................................................................... iii Acknowledgements ....................................................................................................... iv Table of contents ........................................................................................................... vi List of figures .............................................................................................................. viii List of tables .................................................................................................................. ix Chapter 1: General introduction ................................................................................. 1 1.1 Parasitism as a driver of population dynamics ................................................... 2 1.2 Host parasite relationships and parasite life cycles ............................................ 5 1.3 Strategies employed by a parasite to increase the likelihood of transmission ... 6 1.4 Parasite-induced malformations ......................................................................... 6 1.5 The parasite Telogaster opisthorchis ............................................................... 10 1.5.1 Hosts of Telogaster opisthorchis...................................................................... 13 1.6 Aims and objectives ......................................................................................... 14 Chapter 2: The effect of trematode Telogaster opisthorchis on the survival and early development of Galaxias anomalus ............................................... 16 2.1 Introduction ...................................................................................................... 17 2.1.1 Aims and hypotheses ........................................................................................ 20 2.2 Materials and methods ..................................................................................... 21 2.2.1 Animal collection and care ............................................................................... 21 2.2.2 Experimental treatments ................................................................................... 22 2.2.3 Clearing and staining protocol ......................................................................... 24 2.2.4 Measures and statistical analyses ..................................................................... 25 vi Table of contents 2.3 Results .............................................................................................................. 27 2.4 Discussion ........................................................................................................ 36 2.4.5 Conclusion ........................................................................................................ 42 Chapter 3 The effect of the trematode Telogaster opisthorchis on the swimming performance of Galaxias anomalus ........................................................ 43 3.1 Introduction ...................................................................................................... 44 3.1.1 Aims and hypotheses ........................................................................................ 48 3.2 Methods ............................................................................................................ 49 3.2.1 Experimental subjects ...................................................................................... 49 3.2.2 Flume tank ........................................................................................................ 49 3.2.3 Swimming tests ................................................................................................ 51 3.2.4 Clearing and staining protocol ......................................................................... 51 3.2.5 Measures and statistical analyses ..................................................................... 52 3.3 Results .............................................................................................................. 53 3.4 Discussion ........................................................................................................ 56 3.4.1 Conclusion ........................................................................................................ 60 Chapter 4: General discussion ................................................................................... 61 4.1 Discussion ........................................................................................................ 62 4.1.1 Further research ................................................................................................ 64 4.1.2 Conclusion ........................................................................................................ 65 References ……………………………………………………………………………67 vii List of figures List of figures Figure 1.1: Malformed Oregon spotted frog (Rana pretiosa) ......................................... 8 Figure
Load more

Recommended publications
  • TESIS DE DOCTORADO Desarrollo De Herramientas Moleculares Para Su Aplicación En La Mejora De La Trazabilidad De Los Alimentos Fátima C
    TESIS DE DOCTORADO Desarrollo de herramientas moleculares para su aplicación en la mejora de la trazabilidad de los alimentos Fátima C. Lago Soriano 2017 Desarrollo de herramientas moleculares para para moleculares Desarrollo de herramientas : DO Fátima Soriano Lago C. TESIS DOCTORA DE la los trazabilidad de alimentos aplicaciónla su mejora de en 2017 Escuela Internacional de Doctorado Fátima C. Lago Soriano TESIS DE DOCTORADO DESARROLLO DE HERRAMIENTAS MOLECULARES PARA SU APLICACIÓN EN LA MEJORA DE LA TRAZABILIDAD DE LOS ALIMENTOS Dirigida por los Doctores: Montserrat Espiñeira Fernández Juan Manuel Vieites Baptista de Sousa Página 1 de 153 AGRADECIMIENTOS Cuando una etapa llega a su fin, es cuando por fin puedes mirar a atrás, respirar profundamente, y acordarte de aquellos que te acompañaron. Del mismo modo, es difícil entender los agradecimientos de una tesis hasta que pones el punto y final. Es en este momento cuando se puede percibir la gratitud que sientes a todas las personas que han estado presentes durante esa etapa, ya bien sea codo a codo o simplemente trayéndote un café calentito en el momento preciso. Pero también es cierto que, entre toda esa gente que ha estado ahí, hay pocas caras que se dibujan clara e intensamente en mi cabeza. En primerísimo lugar, me gustaría dar las gracias de una manera muy especial a Montse por muchos, muchísimos motivos: por darme cariño y amistad desde el día en que nos conocimos; porque a lo largo de esta década hemos compartido muchísimos momentos alegres, acompañados de risas y carcajadas, pero también los más tristes de mi vida, inundados de lágrimas y angustia; por estar ahí para lo que sea, para todo, y tener siempre tendida su mano amiga; por escucharme una y otra vez, sin cansarse, y aconsejarme sabiamente; por confiar en mí y guiarme, no solo durante el desarrollo de esta tesis, sino también en mi formación y día a día; por su eterna paciencia;… y, sobre todo, por poner en mi vida al “morenocho”, ese pequeño loquito tímido que me comería a besos.
    [Show full text]
  • Comment on G Marty Dcoument
    Critique of the Document “Information Regarding Concerns about Farmed Salmon - Wild Salmon Interactions” Presented to the Provincial Government of British Columbia by Gary Marty, D.V.M., Ph.D., Diplomate, A.C.V.P. of the British Columbia Ministry of Agriculture, Animal Health Centre, Abbotsford. Authors of this critique: Lawrence M. Dill1, Martin Krkosek2, Brendan Connors3, Stephanie J. Peacock4, Andrew W. Bateman5, Richard Routledge6, Mark A. Lewis7, and John Reynolds8 1 Professor Emeritus, Department of Biological Sciences, Simon Fraser University 2 Assistant Professor, Department of Ecology and Evolutionary Biology, University of Toronto 3 Senior Systems Ecologist, ESSA Technologies, and Adjunct Professor, Department of Biological Sciences, Simon Fraser University 4 PhD Candidate, Department of Biological Sciences, University of Alberta 5 Postdoctoral Fellow, Department of Biological Sciences, University of Alberta and Department of Ecology and Evolutionary Biology, University of Toronto 6 Professor, Department of Statistics and Actuarial Science, Simon Fraser University 7 Professor and Senior Canada Research Chair, Departments of Biological Sciences and Mathematical and Statistical Sciences, University of Alberta 8 Professor and Tom Buell BC Leadership Chair in Aquatic Conservation, Department of Biological Sciences, Simon Fraser University Background The document, “Information Regarding Concerns about Farmed Salmon - Wild Salmon Interactions,” dated March 16, 2015, was presented to Ministers Thompson and Letnik of the Government of British Columbia (BC) with the intention of providing scientific information upon which to base management and policy decisions regarding wild and farmed salmon in British Columbia. Collectively, we are a group of scientists, mostly academic, whose research expertise includes salmon and infectious diseases (here we refer to infectious diseases in the broadest sense as those that may arise from parasitic, viral or bacterial pathogens).
    [Show full text]
  • Cumulative Factors Potentially Impacting Wild Salmon Declines Kristina M
    Evolutionary Applications Evolutionary Applications ISSN 1752-4571 REVIEWS AND SYNTHESIS Infectious disease, shifting climates, and opportunistic predators: cumulative factors potentially impacting wild salmon declines Kristina M. Miller,1,2 Amy Teffer,3 Strahan Tucker,1 Shaorong Li,1 Angela D. Schulze,1 Marc Trudel,1,3 Francis Juanes,3 Amy Tabata,1 Karia H. Kaukinen,1 Norma G. Ginther,1 Tobi J. Ming,1 Steven J. Cooke,6 J. Mark Hipfner,5 David A. Patterson4 and Scott G. Hinch2 1 Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC, Canada 2 Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada 3 Biology Department, University of Victoria, Victoria, BC, Canada 4 Fisheries and Oceans Canada, School of Resource and Environmental Management, Simon Fraser University, Science Branch, Burnaby, BC, Canada 5 Environment Canada, Wildlife Research Division, Delta, BC, Canada 6 Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton Univerisy, Ottawa, ON, Canada Keywords Abstract climate, coevolution, cumulative impacts, ecological impacts, infectious disease, Emerging diseases are impacting animals under high-density culture, yet few microparasite, predation, wild salmon studies assess their importance to wild populations. Microparasites selected for enhanced virulence in culture settings should be less successful maintaining infec- Correspondence tivity in wild populations, as once the host dies, there are limited opportunities Kristina M. Miller, Pacific Biological Station,
    [Show full text]
  • Distribution and Coinfection of Microparasites and Macroparasites in Juvenile Salmonids in Three Upper Willamette River Tributaries
    AN ABSTRACT OF THE THESIS OF Sean Robert Roon for the degree of Master of Science in Microbiology presented on December 9, 2014. Title: Distribution and Coinfection of Microparasites and Macroparasites in Juvenile Salmonids in Three Upper Willamette River Tributaries. Abstract approved: ______________________________________________________ Jerri L. Bartholomew Wild fish populations are typically infected with a variety of micro- and macroparasites that may affect fitness and survival, however, there is little published information on parasite distribution in wild juvenile salmonids in three upper tributaries of the Willamette River, OR. The objectives of this survey were to document (1) the distribution of select microparasites in wild salmonids and (2) the prevalence, geographical distribution, and community composition of metazoan parasites infecting these fish. From 2011-2013, I surveyed 279 Chinook salmon Oncorhynchus tshawytscha and 149 rainbow trout O. mykiss for one viral (IHNV) and four bacterial (Aeromonas salmonicida, Flavobacterium columnare, Flavobacterium psychrophilum, and Renibacterium salmoninarum) microparasites known to cause mortality of fish in Willamette River hatcheries. The only microparasite detected was Renibacterium salmoninarum, causative agent of bacterial kidney disease, which was detected at all three sites. I identified 23 metazoan parasite taxa in these fish. Nonmetric multidimensional scaling of metazoan parasite communities reflected a nested structure with trematode metacercariae being the basal parasite taxa at all three sites. The freshwater trematode Nanophyetus salmincola was the most common macroparasite observed at three sites. Metacercariae of N. salmincola have been shown to impair immune function and disease resistance in saltwater. To investigate if N. salmincola affects disease susceptibility in freshwater, I conducted a series of disease challenges to evaluate whether encysted N.
    [Show full text]
  • Assessment of the Risk to Norwegian Biodiversity and Aquaculture from Pink Salmon
    VKM Report 2020: 01 Assessment of the risk to Norwegian biodiversity and aquaculture from pink salmon (Oncorhynchus gorbuscha) Scientific Opinion of the Panel on Alien Organisms and Trade in Endangered Species of the Norwegian Scientific Committee for Food and Environment Report from the Norwegian Scientific Committee for Food and Environment (VKM) 2020: 01 Assessment of the risk to Norwegian biodiversity and aquaculture from pink salmon (Oncorhynchus gorbuscha). Scientific Opinion of the Panel on Alien Organisms and Trade in Endangered Species (CITES) of the Norwegian Scientific Committee for Food and Environment. 15.01.2020 ISBN: 978-82-8259-334-2 ISSN: 2535-4019 Norwegian Scientific Committee for Food and Environment (VKM) Po 222 Skøyen N – 0213 Oslo Norway Phone: +47 21 62 28 00 Email: [email protected] vkm.no vkm.no/english Cover photo: Colourbox Suggested citation: VKM, Kjetil Hindar, Lars Robert Hole, Kyrre Kausrud, Martin Malmstrøm, Espen Rimstad, Lucy Robertson, Odd Terje Sandlund, Eva B. Thorstad, Knut Wiik Vollset, Hugo de Boer, Katrine Eldegard, Johanna Järnegren, Lawrence Kirkendall, Inger Måren, Anders Nielsen, Erlend B. Nilsen, Eli Rueness and Gaute Velle (2020). Assessment of the risk to Norwegian biodiversity and aquaculture from pink salmon (Oncorhynchus gorbuscha). Scientific Opinion of the Panel on Alien Organisms and Trade in Endangered Species (CITES). VKM report 2020:01, ISBN: 978-82-8259-334-2, ISSN: 2535-4019. Norwegian Scientific Committee for Food and Environment (VKM), Oslo, Norway. VKM Report 2020: 01 Assessment of the risk to Norwegian biodiversity and aquaculture from pink salmon (Oncorhynchus gorbuscha) Preparation of the opinion The Norwegian Scientific Committee for Food and Environment (Vitenskapskomiteen for mat og miljø, VKM) appointed a project group to ansver the mandate.
    [Show full text]
  • Crazy & Ambitious
    CRAZY & AMBITIOUS CONFERENCE 2017 8-10 MAY 2017, WELLINGTON, NEW ZEALAND Conference Handbook & Book of Abstracts CRAZY & AMBITIOUS NOT YOUR USUAL NATIONAL MEETING 8-10 MAY 2017 / TE PAPA, WELLINGTON New Zealand’s Biological Heritage Ngā Koiora Tuku Iho National Science Challenge Wifi Password: events Name: CRAZY & AMBITIOUS CONFERENCE 2017 8-10 MAY 2017, WELLINGTON, NEW ZEALAND We are very grateful for the support of our Conference Sponsors and Challenge Parties. CHALLENGE HOST AND CONFERENCE PARTNER CONFERENCE SPONSORS CHALLENGE PARTIES PAGE 2 CRAZY & AMBITIOUS CONFERENCE 2017 8-10 MAY 2017, WELLINGTON, NEW ZEALAND Welcome Nau mai, nau mai, nau mai: ki te hui ‘Pōrangi me te Awhero’ o Te Wero Pūtaiao mo Ngā koiora tuku iho i konei i Te Papa i roto i Te Whanganui-a-Tara. Welcome to the ‘Crazy and Ambitious’ conference of the New Zealand’s Biological Heritage National Science Challenge here at Te Papa in Wellington! This is our first national meeting, and we always wanted to try something different. Our vision is to host a gathering that is ‘not your usual science conference’ – rather, a mix of perspectives from the wider Challenge communuty: scientists, community groups and NGOs, primary industry, politicians, and all our Challenge Parties. The conference programme reflects strong involvement of Māori: scientists, communities, and the private sector. We’re also lucky to host the first visit of our International Science Advisory Panel and other Contents international speakers: their global perspectives will bring another dimension again to the programme. All our speakers have been asked Sponsors ............................................2 to put forward their big, bold and unusal (crazy and ambitious!) ideas over the next three days.
    [Show full text]
  • Rosten, Lyn, K. True, E. Wiseman, K
    National Wild Fish Health Survey California-Nevada Fish Health Center Annual Report for fiscal year 2005 National Wild Fish Health Survey Annual Progress Report FY 2005 Prepared by Lyn Rosten and Kimberly True California-Nevada Fish Health Center Center staff conducted the National Wild Fish Health Survey (NWFHS) in the 2004/2005 fiscal year by collecting fish tissue samples and performing laboratory tests for major fish pathogens in accordance with standardized procedures (NWFHS Laboratory Procedures Manual – 2005, ). This data is entered into a national database and is accessible to the public and resource managers, via the web, and can be viewed at: http://wildfishsurvey.fws.gov/ or http://www.esg.montana.edu/nfhdb/ Kimberly True, Assistant Project Leader Lyn Rosten, Biological Science Technician Eric Wiseman, Fishery Biologist Ken Nichols, Fishery Biologist Scott Foott, Project leader Ron Stone, Fishery Biologist Also assisted with field collections and lab work. 2 Abstract The National Wild Fish Survey (NWFHS), conducted by the U.S. Fish and Wildlife Service’s Fish Health Centers, assesses the prevalence and distribution of major fish pathogens in wild fish populations. In 2004-2005, the California-Nevada Fish Health Center (Ca-Nv FHC) focused on disease monitoring in the upper Klamath River basin. Pathogens associated with diseased fish in the Klamath River include bacteria (Flavobacterium columnare and motile aeromonad bacteria), digenetic trematode (presumptive Nanophyetus salmincola) and myxozoan parasites (Parvicapsula minibicornis and Ceratomyxa shasta). The incidence of two parasites Ceratomyxa shasta and Parvicapsula minibicornis in juvenile chinook salmon is of special concern. Another focus in 2004-2005 was done in collaboration with Nevada Division of Wildlife’s regional biologists.
    [Show full text]
  • Freshwater and Marine Prevalence of Nanophyetus Infections in Puget Sound
    Freshwater and Marine Prevalence of Nanophyetus infections in Puget Sound. Martin Chen1,Robert Conrad1,Bruce Stewart1, Paul Hershberger2 and Kevin Snekvik3 1Northwest Indian Fisheries Commission, OlympiaFish Health Assessment of outmigrating steelhead 2USGS‐Western Fisheries Research Center, Marrowstone Island Marine Field Station, Nordland 3Washington Animal Disease Diagnostic Laboratory, Washington State University, Pullman Nanophyetus salmincola lifecycle The first intermediate host is a snail Juga plicifera Juga silicula (Juga formerly known as Oxytrema) Salmon Poisoning Disease of dogs is caused by the bacterium Neorickettsia helminthoeca carried by Nanophyetus salmincola Remove posterior kidney and count numbers of metacercaria. (59) Kidney samples were placed in a sample bag, compressed between two glass plates and examined at 15X. Study Questions: 1. Is there a correlation between the lower return of steelhead to South Sound Rivers and the presence and intensity of N. salmincola infection? 2. Does the intensity of infection as outmigration proceeds suggest a causal effect between N. salmincola and poor marine survival? Sampling Design 5 Puget Sound watersheds Hatcheries Traps Lower River / Estuary 3 Offshore Areas • Whidbey Basin • Green / Duwamish • Nisqually % Prevalence of Nanophyetus salmincola, other parasites and organ pathology in steelhead smolts from four Puget Sound river basins in 2014. (n)= sample size Site N. Kidney Sanguinicola Gill Heart salmincola Myxosporean Pathology Pathology Skagit R. 5 (21) 40 (5) 0 (5) 0 (5) 0 (5) Whidbey 7 (42) 36 (31) 3 (31) 0 (31) 3 (31) Offshore Snohomish R. 0 (7) 20 (5) 0 (5) 0 (5) 0 (5) Green R. 73 (112) 12 (89) 0 (89) 28 (89) 45 (89) South‐Central 94 (15) 36 (14) 14 (14) 7 (14) 29 (14) Offshore Nisqually R.
    [Show full text]
  • D070p001.Pdf
    DISEASES OF AQUATIC ORGANISMS Vol. 70: 1–36, 2006 Published June 12 Dis Aquat Org OPENPEN ACCESSCCESS FEATURE ARTICLE: REVIEW Guide to the identification of fish protozoan and metazoan parasites in stained tissue sections D. W. Bruno1,*, B. Nowak2, D. G. Elliott3 1FRS Marine Laboratory, PO Box 101, 375 Victoria Road, Aberdeen AB11 9DB, UK 2School of Aquaculture, Tasmanian Aquaculture and Fisheries Institute, CRC Aquafin, University of Tasmania, Locked Bag 1370, Launceston, Tasmania 7250, Australia 3Western Fisheries Research Center, US Geological Survey/Biological Resources Discipline, 6505 N.E. 65th Street, Seattle, Washington 98115, USA ABSTRACT: The identification of protozoan and metazoan parasites is traditionally carried out using a series of classical keys based upon the morphology of the whole organism. However, in stained tis- sue sections prepared for light microscopy, taxonomic features will be missing, thus making parasite identification difficult. This work highlights the characteristic features of representative parasites in tissue sections to aid identification. The parasite examples discussed are derived from species af- fecting finfish, and predominantly include parasites associated with disease or those commonly observed as incidental findings in disease diagnostic cases. Emphasis is on protozoan and small metazoan parasites (such as Myxosporidia) because these are the organisms most likely to be missed or mis-diagnosed during gross examination. Figures are presented in colour to assist biologists and veterinarians who are required to assess host/parasite interactions by light microscopy. KEY WORDS: Identification · Light microscopy · Metazoa · Protozoa · Staining · Tissue sections Resale or republication not permitted without written consent of the publisher INTRODUCTION identifying the type of epithelial cells that compose the intestine.
    [Show full text]
  • Trout (Oncorhynchus Mykiss)
    Acta vet. scand. 1995, 36, 299-318. A Checklist of Metazoan Parasites from Rainbow Trout (Oncorhynchus mykiss) By K. Buchmann, A. Uldal and H. C. K. Lyholt Department of Veterinary Microbiology, Section of Fish Diseases, The Royal Veterinary and Agricultural Uni­ versity, Frederiksberg, Denmark. Buchmann, K., A. Uldal and H. Lyholt: A checklist of metazoan parasites from rainbow trout Oncorhynchus mykiss. Acta vet. scand. 1995, 36, 299-318. - An extensive litera­ ture survey on metazoan parasites from rainbow trout Oncorhynchus mykiss has been conducted. The taxa Monogenea, Cestoda, Digenea, Nematoda, Acanthocephala, Crustacea and Hirudinea are covered. A total of 169 taxonomic entities are recorded in rainbow trout worldwide although few of these may prove synonyms in future anal­ yses of the parasite specimens. These records include Monogenea (15), Cestoda (27), Digenea (37), Nematoda (39), Acanthocephala (23), Crustacea (17), Mollusca (6) and Hirudinea ( 5). The large number of parasites in this salmonid reflects its cosmopolitan distribution. helminths; Monogenea; Digenea; Cestoda; Acanthocephala; Nematoda; Hirudinea; Crustacea; Mollusca. Introduction kova (1992) and the present paper lists the re­ The importance of the rainbow trout Onco­ corded metazoan parasites from this host. rhynchus mykiss (Walbaum) in aquacultural In order to prevent a reference list being too enterprises has increased significantly during extensive, priority has been given to reports the last century. The annual total world pro­ compiling data for the appropriate geograph­ duction of this species has been estimated to ical regions or early records in a particular 271,478 metric tonnes in 1990 exceeding that area. Thus, a number of excellent papers on of Salmo salar (FAO 1991).
    [Show full text]
  • Effect of Nanophyetus Salmincola and Bacterial Co-Infection on Mortality of Juvenile Chinook Salmon
    Journal of Aquatic Animal Health 27:209–216, 2015 C American Fisheries Society 2015 ISSN: 0899-7659 print / 1548-8667 online DOI: 10.1080/08997659.2015.1094150 ARTICLE Effect of Nanophyetus salmincola and Bacterial Co-Infection on Mortality of Juvenile Chinook Salmon Sean R. Roon and Julie D. Alexander Department of Microbiology, Oregon State University, 226 Nash Hall, Corvallis, Oregon 97331, USA Kym C. Jacobson National Oceanographic and Atmospheric Administration–Fisheries, Northwest Fisheries Science Center, Newport Research Station, 2030 Southeast OSU Drive, Newport, Oregon 97365, USA Jerri L. Bartholomew* Department of Microbiology, Oregon State University, 226 Nash Hall, Corvallis, Oregon 97331, USA Abstract The freshwater trematode Nanophyetus salmincola has been demonstrated to impair salmonid immune function and resistance to the marine pathogen Vibrio anguillarum, potentially resulting in ocean mortality. We examined whether infection by the parasite N. salmincola similarly increases mortality of juvenile Chinook Salmon On- corhynchus tshawytscha when they are exposed to the freshwater pathogens Flavobacterium columnare or Aeromonas salmonicida, two bacteria that juvenile salmonids might encounter during their migration to the marine environ- ment. We used a two-part experimental design where juvenile Chinook Salmon were first infected with N. salmincola through cohabitation with infected freshwater snails, Juga spp., and then challenged with either F. columnare or A. salmonicida. Cumulative percent mortality from F. columnare infection was higher in N. salmincola-parasitized fish than in nonparasitized fish. In contrast, cumulative percent mortality from A. salmonicida infection did not differ between N. salmincola-parasitized and nonparasitized groups. No mortalities were observed in the N. salmin- cola-parasitized-only and control groups from either challenge.
    [Show full text]
  • The Parasite Release Hypothesis and the Success of Invasive Fish in New Zealand
    http://researchcommons.waikato.ac.nz/ Research Commons at the University of Waikato Copyright Statement: The digital copy of this thesis is protected by the Copyright Act 1994 (New Zealand). The thesis may be consulted by you, provided you comply with the provisions of the Act and the following conditions of use: Any use you make of these documents or images must be for research or private study purposes only, and you may not make them available to any other person. Authors control the copyright of their thesis. You will recognise the author’s right to be identified as the author of the thesis, and due acknowledgement will be made to the author where appropriate. You will obtain the author’s permission before publishing any material from the thesis. The parasite release hypothesis and the success of invasive fish in New Zealand A thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Biological Science at The University of Waikato by Keshi Zhang The University of Waikato 2012 Abstract Non-indigenous species are commonly released from their native enemies, including parasites, when they are introduced into new geographical areas. This has been referred to as the enemy release hypothesis and more strictly as the parasite release hypothesis. The loss of parasites is commonly inferred to explain the invasiveness of non-indigenous species. I examined parasite release in New Zealand non-indigenous freshwater fishes. A literature review was undertaken in order to collate lists of the known parasite fauna of 20 New Zealand non-indigenous freshwater fish species.
    [Show full text]