Data from: Home ground advantage: local Atlantic salmon have higher reproductive fitness than dispersers in the wild

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.