Some Results of Studies on Pink Salmon Oncorhynchus gorbuscha’s Number Dynamics on the Northeastern Coasts of Sakhalin Island

Abstract

Data characterizing the number of individual generations of pink salmon Oncorhynchus gorbuscha (the volume of harvest, entry of spawners into the rivers, and subsequent downstream migration of fry) in the northern and southern regions of the northeast coast of Sakhalin Island are analyzed. The analysis of the ratio of the number of spawners on spawning grounds to juvenile salmon migrating downstream suggests that the efficiency of reproduction in the mountain pink salmon-type rivers of the southern part of the coast is higher than in the relatively large plain rivers of the northern part. It has been shown that the growth in the number of pink salmon observed in recent years was mainly due to an increase in the survival of generations during the marine period of life.