Direction and magnitude of natural selection on body size differ among age-classes of seaward-migrating Pacific salmon.

ABSTRACT: Due to the mediating role of body size in determining fitness, the "bigger-is-better" hypothesis still pervades evolutionary ecology despite evidence that natural selection on phenotypic traits varies in time and space. For Pacific salmon (genus Oncorhynchus), most individual studies quantify selection across a narrow range of sizes and ages; therefore, uncertainties remain concerning how selection on size may differ among diverse life histories. Here, we quantify the direction and magnitude of natural selection on body size among age-classes of multiple marine cohorts of O. nerka (sockeye salmon). Across four cohorts of seaward migrants, we calculated standardized selection differentials by comparing observed size distributions of out-migrating juvenile salmon to back-calcul

SUBMITTER: Ulaski ME 

PROVIDER: S-EPMC7463379 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature