ABSTRACT
The genetic population structure in 4 spawning aggregations from the Bering Sea of walleye pollock (Theragra chalcogramma, Pallas), that occupies a central place in ecosystems of the North Pacific and is an important object of fisheries, was investigated with the ten microsatellite loci Tch5, Tch10, Tch11, Tch12, Tch14, Tch16, Tch17, Tch19, Tch20 and Tch22. The spatially distanced sample from Sea of Okhotsk was a referent group. The polymorphism of the markers used accounted for 100%, heterozygozity ranged from 41 to 95% in the different populations. It was shown that the aggregations of interest are in goodness-to-fit HWE at whole,but Sea of Okhotsk sample demonstrated the sex bias in the null-allele number in locus Tch16. Loci Tch10, Tch20 and Tch22 were of the most discriminate power. The genetic distances between all pairs of samples were typical for marine fishes. The sample from underwater Shirshov ridge region that is the natural geographic barrier for Olutor-Karagin and Koryak walleye pollock stocks is presumably of mixed genesis. As evident from scatter plots of F(ST) and spatial autocorrelation approach, data obtained (when Shirshov sample is eliminated) are under isolation by distance model on a broad spatial scale. The influence of abiotic factors on the population structure of the Bering Sea walleye pollock is supposed.
