Some Results from Studies on Number Dynamics of Pink Oncorhynchus gorbuscha and Chum O. keta Salmons on the Northwest Coast of Sakhalin Island

Resumo

The data characterizing the number of separate generations of pink salmon Oncorhynchus gorbuscha and chum salmon O. keta on the northwest coast of Sakhalin Island (harvest volumes, entries of spawners into rivers and the subsequent downstream migration of the juvenile fish) are analyzed. According to the dynamics of harvests and biological indicators of fish, it has been shown that fishing is based on the approaches to the shore of different groups of these fish species. If the presence of groupings for chum salmon is associated with the migration of fish of different races (summer and autumn) and of different origin (from the Amur River and small rivers of the northwestern coast of Sakhalin and the adjacent mainland coast), then it is mainly due to the approach of fish of local origin but of different temporal forms for pink salmon.