Proportion of initial genetic variability remaining in a simulated chinook salmon population after periods of time up to 100 years. N b is the effective number of breeders per year. Distribution of alleles at various frequencies found in samples from 177 chinook salmon populations in the Pacific Northwest. Table 1 . Average heterozygosity values a for spring and fall chinook salmon from the Columbia River Basin.
Regional values are means based on the number of stocks indicated in parentheses.
A number of loci known or suspected to be monomorphic were not included in the analysis, so values shown are relative rather than unbiased estimates of total heterozygosity.