Genetic Variation and Population Structure of Pacific Ocean Perch (Sebastes alutus)

Abstract

We conducted an allozyme analysis of 27 collections representing over 1500 individuals of Pacific ocean perch (Sebastes alutus). Data were gathered from 25 presumptive loci of which 20% were polymorphic. Average observed heterozygosity was 0.069. Samples originated from throughout the commercially important range of the species from the Washington coast to the Bering Sea. Pacific ocean perch are highly similar throughout the range, with only a slight amount of population differentiation (FST = 0.023). However, a cline of gene frequencies within the Gulf of Alaska exists at Ada2, and there are significant frequency differences between the extremes of the range for several additional loci. There is no evidence of an interruption of gene flow between the western Gulf of Alaska and the Bering Sea. Stock delineations based on age structure, age–length relationships, and ages at maturity were not supported by the allozyme data and are either influenced by nongenetic environmental factors or are under a selective regime not measured by allozyme analyses.