Genetic monitoring of northern sea of Okhotsk populations of pink salmon (<Emphasis Type="Italic">Oncorhynchus gorbuscha</Emphasis>)

Results from the 1993–2004 genetic monitoring of pink salmon populations reproducing in the rivers of Tauy Bay on the Sea of Okhotsk are analyzed. A statistically significant heterogeneity of samples as determined by gene frequencies is found only in the pink salmon generations of even years. The genetic differentiation of samples from even years (G_ST = 1.39 ± 0.41) is higher than that of odd years (G_ST = 0.740.09). The pattern for the indicator of genetic variability (heterozygosity) is exactly the opposite (0.076 ± 0.02564 vs. 0.8760 ± 0.01950). Consequently, the lower-heterozygosity samples of lines from even years are on average more genetically distinct than the analogous indicator for odd years. In addition, the interpopulation ratio in the general value of genetic diversity is almost always smaller than both the intraannual and interannual ratios, leading to a low level of interpopulation genetic differences. Cluster analysis reveals that most 2001–2004 samples are grouped separately from samples collected prior to 2000. In our opinion, the reason for this could be the turnover of a numerically dominant generation of northern Sea of Okhtosk pink salmon and the change in gene frequencies accompanying it.