Origins and genetic diversity among Atlantic salmon recolonizing upstream areas of a large South European river following restoration of connectivity and stocking

• Published in: Conservation Genetics
• Main Authors: Perrier, Charles, Le Gentil, Jérôme, Ravigné, Virginie, Gaudin, Philippe, Salvado, Jean-Claude
• Other Authors: Écologie et santé des écosystèmes (ESE), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Département de Biologie, Université Laval Québec (ULaval), Ecologie Comportementale et Biologie des Populations de Poissons (ECOBIOP), Institut National de la Recherche Agronomique (INRA)-Université de Pau et des Pays de l'Adour (UPPA), Biologie et Génétique des Interactions Plante-Parasite (UMR BGPI), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), This work was funded by the European Union INTERREG IIIB program Atlantic Salmon Arc Project (ASAP) and the European Union INTERREG IVB program Atlantic Arc Resource Conservation (AARC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2014
• Subjects: connectivity; assignment; salmo salar; dam; genetic diversity; recolonization; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Atlantic salmon; Salmo salar
• Online Access: https://hal.science/hal-01210223; https://doi.org/10.1007/s10592-014-0602-3

International audience The restoration and maintenance of habitat connectivity are major challenges in conservation biology. These aims are especially critical for migratory species using corridors that can be obstructed by anthropogenic barriers. Here, we explored the origins and genetic diversity of Atlantic salmon (Salmo salar) recolonizing upstream areas of the largest South European Atlantic salmon population (Adour drainage, France) following restoration of connectivity and stocking. We genotyped 1,009 juvenile individuals, sampled either in continuously inhabited downstream sites or in recently reconnected and recolonized upstream locations, at 12 microsatellite loci. We found significant fine scale genetic structure, with three main genetic clusters corresponding to the Nive, Nivelle and Gaves rivers. Within each of these clusters, samples collected in continuously inhabited and recently recolonized sites had comparable allelic richness and effective population sizes and were only weakly differentiated. Genetic structure among basins was also similar among continuously inhabited and recently recolonized sites. The majority of the individuals sampled from recently recolonized sites were assigned to neighboring continuously inhabited downstream sites, but noticeable proportions of fish were assigned to samples collected in more distant sites or identified as putative hybrids. Overall, this study suggests that the restoration of accessibility to upstream areas can allow for the recolonization and effective reproduction of Atlantic salmon from proximate downstream refugia, which does not decrease local diversity or disrupt existing genetic structure