Co-existing populations of Pacific ocean perch, Sebastes alutus in Queen Charlotte Sound, British Columbia

Variation at five microsatellite loci (Sall1 Sal2, Sal3, Sal4 and Sal5) was examined in approximately 1300 Pacific ocean perch (Sebastes alutus) sampl ed fro 14 coastal sites in British Columbia, Canada. Mean observed heterozy gosities by locus ranged from 71% to 88%, and by sample ranged from 75% to 84%. Theta values ranged from 0 to 0.04 over the five loci, and averaged 0. 015. Among Pacific ocean perch samples, theta ranged from 0.001 to 0.056. C anonical discriminate analysis of multilocus genotypes and neighbour-joinin g analysis of pairwise genetic distances between samples both indicated the presence of three populations, one off the west coast of Vancouver Island (the Vancouver Island population) and two co-existing populations in Queen Charlotte Sound, Dixon Entrance and along the west coast of the Queen Charl otte Islands (the eastern and western QCI populations). Pacific ocean perch of the eastern and western QCI populations were caught in close proximity to each other, but individual sam les showed little evidence of admixture. Fall and spring samples collected within geographic areas were genetically similar, indicating seasonally stable population structure. Restricted gene flow between the Vancouver Island and the two more northerly populations m ay result from limited adult dispersal and larval retention within the Cali fornia Current and Alaska Gyre, respectively, but the presence of two popul ations within Queen Charlotte Sound cannot be explained entirely by larval retention hypotheses. The presence of two Pacific ocean perch populations i n central British Columbia has implications for fisheries management.