GENETIC DIFFERENTIATION OF CHUM SALMON OF THE AMUR BASIN

Genetic differentiation of the chum salmon of the Amur basin was exami ned using electrophoretic analysis of 16 allozyme loci, nine of which were polymorphic. Thirty samples collected in 1983 - 1990 in the Amur estuary, in the lower Amur, and in several tributaries (rivers Amgun', Anyui, Tunguska, Bira, and Bidzhan) were analyzed. A total of more th an 3100 individuals were scored. The test for homogeneity of allele fr equencies and the cluster analysis of the samples and groups, which wa s organized according to their geographic location, demonstrated the s table population structure of the chum salmon populations. The main po rtion of the intersample genetic diversity (2.23% of the total) is all ocated to the divergence of the summer and autumn races (1.28%). The E STD and IDHP-3 * loci showed the highest difference between the races . The amount of genetic differentiation within the summer race was ver y low. In the autumn race, it was much higher due to the genetic diver gence of the local shoals from the upper tributaries. Among the Russia n Far East populations, the summer and autumn races of chum salmon are closest to the populations of northern and eastern Sakhalin and of Pr imorskii region. The specificity of the Amur chum salmon genetic struc ture allows one to identify it in sea catches, while its local genetic differentiation within the Amur basin should be considered in rationa l resource management and preservation and restoration measures.