Changes in the genetic structure of Atlantic salmon populations over four decades reveal substantial impacts of stocking and potential resiliency

• Published in: Ecology and Evolution
• Main Authors: Perrier, Charles, Guyomard, René, Baglinière, Jean-Luc, Nikolic, Natacha, Evanno, Guillaume
• Other Authors: Écologie et santé des écosystèmes (ESE), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Génétique Animale et Biologie Intégrative (GABI), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, This study was supported by grants from INRA and Région Basse-Normandie to C. P. and by the European Atlantic Salmon Arc Project.
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: conservation; population genetic; salmo salar; stocking; temporal stability; [SDV.SA]Life Sciences [q-bio]/Agricultural sciences; Atlantic salmon; Salmo salar
• Online Access: https://hal.archives-ouvertes.fr/hal-01001102; https://hal.archives-ouvertes.fr/hal-01001102/document; https://hal.archives-ouvertes.fr/hal-01001102/file/2013_Perrier_Ecology_and_Evolution_1.pdf; https://doi.org/10.1002/ece3.629

Chantier qualité GA While the stocking of captive-bred fish has been occurring for decades and has had substantial immediate genetic and evolutionary impacts on wild populations, its long-term consequences have only been weakly investigated. Here, we conducted a spatiotemporal analysis of 1428 Atlantic salmon sampled from 1965 to 2006 in 25 populations throughout France to investigate the influence of stocking on the neutral genetic structure in wild Atlantic salmon (Salmo salar) populations. On the basis of the analysis of 11 microsatellite loci, we found that the overall genetic structure among populations dramatically decreased over the period studied. Admixture rates among populations were highly variable, ranging from a nearly undetectable contribution from donor stocks to total replacement of the native gene pool, suggesting extremely variable impacts of stocking. Depending on population, admixture rates either increased, remained stable, or decreased in samples collected between 1998 and 2006 compared to samples from 1965 to 1987, suggesting either rising, long-lasting or short-term impacts of stocking. We discuss the potential mechanisms contributing to this variability, including the reduced fitness of stocked fish and persistence of wild locally adapted individuals.