Genetic Variation in Populations of Steelhead Trout (Salmo gairdneri) in British Columbia

Abstract

The geographic distributions of biochemical genetic variants at four loci in indigenous British Columbia steelhead (Salmo gairdneri) populations indicated that there was a large-scale subdivision of the species into three major groups. At intermediate geographic scales, gene frequencies were uniform over unexpectedly large areas, but at the smallest geographic scale, significant differentiation was observed between populations in adjacent streams. This pattern of variation supports the view that this species is subdivided into a large number of semi-isolated populations each having the potential to evolve adaptations to local environmental conditions.