Biochemical Genetic Stock Identification of Chum Salmon (Oncorhynchus keta) in Southern British Columbia

Abstract

We used electrophoresis to examine genetic variability of 33 chum salmon (Oncorhynchus keta) stocks in southern British Columbia and used differences in genotypic frequencies among these stocks for estimating stock compositions in a weekly fishery in upper Johnstone Strait. Seven polymorphic loci were used for stock identification. Chum salmon from the Fraser River, Bute and Toba inlets, Vancouver Island, and the southern Mainland had significantly different allelic frequencies, but there was also significant heterogeneity in allelic frequencies at some loci within each region. Allelic frequencies were generally stable over a 2-yr period in nine stocks for which consecutive annual sampling was conducted. There was no significant two-locus linkage disequilibrium for the chum salmon stocks surveyed. Cluster analysis indicated that Fraser River and Bute and Toba Inlet stocks were distinctive, but Vancouver Island and Mainland stocks were not. The timing and relative abundance of Fraser River chum salmon in upper Johnstone Strait as estimated by electrophoretic analysis was confirmed by an in-river test fishery in the Fraser River.