Contrasting patterns of population structure and breeding dispersal exhibited between sister taxa in a small river system: new insights from population genetics and sibling analysis on Atlantic salmon (Salmo salar) and brown trout (Salmo trutta).

backgroundThe movement of individuals from one breeding site to another (i.e. breeding dispersal) can have important consequences for fitness and population genetics. Whilst closely related species are expected to be phenotypically similar in many respects, they can nevertheless exhibit important differences in behaviour and ecology that can have repercussions for population structure.

methodsHere we use genetic information (microsatellite data) collected on two sister species - Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) - that overlap in their spawning and freshwater rearing habitats within a small (ca. 100 km

resultsThe I

conclusionsOur results support the hypothesis that Atlantic salmon engage in more spatially extensive breeding dispersal behaviour than brown trout, which in turn may explain why trout but not salmon exhibit population genetic structure in this system. Collectively, our findings showcase how the same genetic data can be used to gain complementary insights into the movement behaviours of individuals and the genetic structuring of populations, with implications for conservation management. They furthermore emphasise a hitherto overlooked role for intra-seasonal breeding dispersal in shaping spatial genetic connectivity in polygamous species.