Genetic Population Structure and Origin of Life History Types in Chinook Salmon in British Columbia, Canada

Abstract
We used protein electrophoresis to examine genetic population structure and origin of life history types of chinook salmon Oncorhynchus tshawytscha in British Columbia, Canada. Among 31 allozyme loci resolved in 91 samples from 63 populations of chinook salmon in rivers and hatcheries throughout British Columbia, population heterozygosities averaged 0.084 (range 0.048–0.108) and were typical of values for populations in other regions. A hierarchical gene diversity analysis indicated that 91.3% of the total allele-frequency diversity was attributable to within-population variability; the remaining 8.7% was attributable to geographic variability among populations, which was partitioned into among-river (3.3%), among-area (3.5%), and among-region (1.9%) components. Two major groups of populations appeared in the principal components analysis and in cluster analysis of genetic distances. A coastal group included populations in four subgroups: Central coast, Georgia Strait, lower Fraser River, and wes...