Life-history genotype explains variation in migration activity in Atlantic salmon (Salmo salar)

Abstract

One of the most important life-history continuums is the fast-slow axis, where fast individuals mature earlier than slow individuals. Fast individuals are predicted to be more active than slow individuals; high activity is required to maintain a fast life-history strategy. Recent meta-analyses revealed mixed evidence for such integration. Here, we test whether known life-history genotypes differ in activity expression by using Atlantic salmon (Salmo salar) as a model. In salmon, variation in Vgll3, a transcription co-factor, explains ~40% of variation in maturation timing. We predicted that the allele related to early maturation (vgll3*E) would be associated with increased activity. We used an automated surveillance system to follow ~1900 juveniles including both migrants and non-migrants (i.e. smolt and parr fish, respectively) in semi-natural conditions over 31 days (~580 000 activity measurements). Against our prediction, vgll3 did not explain variation in activity in pooled migrant and non-migrant data. However, in migrants, vgll3 explained variation in activity according to our prediction in a sex-dependent manner. Specifically, in females the vgll3*E allele was related to increasing activity, whereas in males the vgll3*L allele (later maturation allele) was related to increasing activity. These sex-dependent effects might be a mechanism maintaining within-population genetic life-history variation.

Life-history genotype explains variation in migration activity in Atlantic salmon ( Salmo salar )

“…The data and R script related to this study are stored in a public repository [45]. Electronic supplementary material is available online [46].…”