While evolutionary responses require heritable variation, estimates of heritability h from wild fish populations remain rare. A 20-year molecular pedigree for a wild Scottish population of Atlantic salmon (Salmo salar) was used to investigate genetic contributions to (co)variation in two important, correlated, phenotypic traits: “sea-age” (number of winters spent at sea prior to spawning) and size-at-maturity (body length just prior to spawning). Sea-age was strongly heritable h = 0.51) and size exhibited moderate heritability h = 0.27). A very strong genetic correlation G = 0.96) between these traits implied the same functional loci must underpin variation in each. Indeed, body size within sea-ages had much lower heritability that did not differ significantly from zero. Thus, within wild S. salar populations, temporal changes in sea-age composition could reflect evolutionary responses, whereas rapid changes of body-size within sea-ages are more likely due to phenotypic plasticity. These inheritance patterns will influence the scope of evolutionary responses to factors such as harvest or climate change and, hence, have management implications for salmonid populations comprising a mix of sea ages.
|Journal||Canadian Journal of Fisheries and Aquatic Sciences|
|Early online date||30 Jul 2018|
|Publication status||Early online date - 30 Jul 2018|