Home ground advantage : Local Atlantic salmon have higher reproductive fitness than dispersers in the wild

• Published in: Science Advances
• Main Authors: Mobley, Kenyon B., Granroth-Wilding, Hanna, Ellmen, Mikko, Vaha, Juha-Pekka, Aykanat, Tutku, Johnston, Susan E., Orell, Panu, Erkinaro, Jaakko, Primmer, Craig R.
• Other Authors: Evolution, Conservation, and Genomics, Organismal and Evolutionary Biology Research Programme, Behavioural Ecology - Candolin Research Lab, Helsinki Institute of Sustainability Science (HELSUS), Institute of Biotechnology
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 2019
• Subjects: GENE FLOW; ADAPTATION; EVOLUTION; SELECTION; PACIFIC; SALAR; DIFFERENTIATION; CONSEQUENCES; IMMIGRANTS; MIGRATION; Ecology; evolutionary biology; Atlantic salmon; Salmo salar
• Online Access: http://hdl.handle.net/10138/300462

A long-held, but poorly tested, assumption in natural populations is that individuals that disperse into new areas for reproduction are at a disadvantage compared to individuals that reproduce in their natal habitat, underpinning the eco-evolutionary processes of local adaptation and ecological speciation. Here, we capitalize on fine-scale population structure and natural dispersal events to compare the reproductive success of local and dispersing individuals captured on the same spawning ground in four consecutive parent-offspring cohorts of wild Atlantic salmon (Salmo salar). Parentage analysis conducted on adults and juvenile fish showed that local females and males had 9.6 and 2.9 times higher reproductive success than dispersers, respectively. Our results reveal how higher reproductive success in local spawners compared to dispersers may act in natural populations to drive population divergence and promote local adaptation over microgeographic spatial scales without clear morphological differences between populations. Peer reviewed