• Open Access

The impact of fishing-induced mortality on the evolution of alternative life-history tactics in brook charr

Authors

  • Véronique Thériault,

    1.  Département de Biologie, Centre Interuniversitaire de Recherche sur le Saumon Atlantique (CIRSA), Université Laval, Cité Universitaire, Québec, QC, Canada
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  • Erin S. Dunlop,

    1.  Institute of Marine Research, Bergen, Norway
    2.  Department of Biology, University of Bergen, Bergen, Norway
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  • Ulf Dieckmann,

    1.  Evolution and Ecology Program, International Institute for Applied Systems Analysis, Laxenburg, Austria
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  • Louis Bernatchez,

    1.  Département de Biologie, Centre Interuniversitaire de Recherche sur le Saumon Atlantique (CIRSA), Université Laval, Cité Universitaire, Québec, QC, Canada
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  • Julian J. Dodson

    1.  Département de Biologie, Centre Interuniversitaire de Recherche sur le Saumon Atlantique (CIRSA), Université Laval, Cité Universitaire, Québec, QC, Canada
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Véronique Thériault, Coastal Oregon Marine Experiment Station, Department of Fisheries and Wildlife, Oregon State University, Hatfield Marine Science Center, 2030 SE Marine Science Drive, Newport, OR 97365, USA. Tel.: 541 867 0206; fax: 541 867 0345; e-mail: veronique.theriault@oregonstate.edu

Abstract

Although contemporary trends indicative of evolutionary change have been detected in the life-history traits of exploited populations, it is not known to what extent fishing influences the evolution of alternative life-history tactics in migratory species such as salmonids. Here, we build a model to predict the evolution of anadromy and residency in an exploited population of brook charr, Salvelinus fontinalis. Our model allows for both phenotypic plasticity and genetic change in the age and size at migration by including migration reaction norms. Using this model, we predict that fishing of anadromous individuals over the course of 100 years causes evolution in the migration reaction norm, resulting in a decrease in average probabilities of migration with increasing harvest rate. Moreover, we show that differences in natural mortalities in freshwater greatly influence the magnitude and rate of evolutionary change. The fishing-induced changes in migration predicted by our model alter population abundances and reproductive output and should be accounted for in the sustainable management of salmonids.

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