A Decrease in the Pink Salmon (Oncorhynchus gorbuscha) Abundance in the Sakhalin–Kuril Region under the Effects of Extreme Environmental Factors

Abstract

An analysis of variations in the abundance of pink salmon on Iturup Island and in four areas of the eastern Sakhalin Island coast in 2007–2016 has shown that year-classes of this species become weaker if they are exposed to the effect of typhoons during their embryonic development in rivers (spawning nests) or juvenile feeding in coastal waters (soon after their downstream migration from rivers). The size of the pink salmon runs to these waters in 2017 completely fits the relationships identified for the previous year. These results indicate the decisive role of extreme environmental factors in the formation of the abundance of pink salmon.