• Open Access

Varying disease-mediated selection at different life-history stages of Atlantic salmon in fresh water

Authors

  • Elvira de Eyto,

    1.  Marine Institute, Newport, Co Mayo, Ireland
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    • These authors contributed equally to this work.

  • Philip McGinnity,

    1.  Department of Zoology, Ecology and Plant Science/Aquaculture and Fisheries Development Centre, University College Cork, Distillery Fields, North Mall, Cork, Ireland
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    • These authors contributed equally to this work.

  • Jisca Huisman,

    1.  Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
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  • Jamie Coughlan,

    1.  Department of Zoology, Ecology and Plant Science/Aquaculture and Fisheries Development Centre, University College Cork, Distillery Fields, North Mall, Cork, Ireland
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  • Sofia Consuegra,

    1.  Aberystwyth University, Institute of Biological, Environmental & Rural Sciences, Aberystwyth, UK
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  • Killian Farrell,

    1.  Marine Institute, Newport, Co Mayo, Ireland
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  • Ciar O’Toole,

    1.  Department of Zoology, Ecology and Plant Science/Aquaculture and Fisheries Development Centre, University College Cork, Distillery Fields, North Mall, Cork, Ireland
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  • Jarle Tufto,

    1.  Department of Mathematical Sciences, Norwegian University of Science and Technology, Trondheim, Norway
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  • Hendrik-Jan Megens,

    1.  Department of Animal Sciences, Wageningen University, Wageningen, the Netherlands
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  • William Jordan,

    1.  Institute of Zoology, Zoological Society of London, Regent’s Park, London, UK
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    • This paper is dedicated to the memory of René Stet, who died in September 2007, and William Jordan, who died in May 2011.

  • Tom Cross,

    1.  Department of Zoology, Ecology and Plant Science/Aquaculture and Fisheries Development Centre, University College Cork, Distillery Fields, North Mall, Cork, Ireland
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  • Rene′ J. M. Stet

    1.  Scottish Fish Immunology Research Centre, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, UK
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    • This paper is dedicated to the memory of René Stet, who died in September 2007, and William Jordan, who died in May 2011.


Elvira de Eyto, Marine Institute, Furnace Newport, Co. Mayo, Ireland. Tel.: 003539842300; fax: 003539842340; e-mail: elvira.deeyto@marine.ie

Abstract

Laboratory studies on associations between disease resistance and susceptibility and major histocompatibility (MH) genes in Atlantic salmon Salmo salar have shown the importance of immunogenetics in understanding the capacity of populations to fight specific diseases. However, the occurrence and virulence of pathogens may vary spatially and temporally in the wild, making it more complicated to predict the overall effect that MH genes exert on fitness of natural populations and over several life-history stages. Here we show that MH variability is a significant determinant of salmon survival in fresh water, by comparing observed and expected genotype frequencies at MH and control microsatellite loci at parr and migrant stages in the wild. We found that additive allelic effects at immunogenetic loci were more likely to determine survival than dominance deviation, and that selection on certain MH alleles varied with life stage, possibly owing to varying pathogen prevalence and/or virulence over time. Our results highlight the importance of preserving genetic diversity (particularly at MH loci) in wild populations, so that they have the best chance of adapting to new and increased disease challenges as a result of projected climate warming and increasing aquaculture.

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