Reproduction of Pacific Salmon (Oncorhynchus) in Rivers Flowing into Terpeniya Bay (Sakhalin Island)

Abstract

The conditions for the reproduction of Pacific salmon of the Oncorhynchus genus in rivers flowing into Terpeniya Bay were assessed. The differences between the rivers of the northern and western parts of the study area were described according to the channel morphology, the faunistic composition of the aquatic biota, and the predominant species of salmon. In the rivers of the northern section (the basin of the Poronai River and Lake Nevskoe), which have both mountain-foothill and plain types of channels, the reproduction of O. gorbusha pink salmon is at a low level. In the rivers of the western section having a pronounced mountain character and a relatively poor ichthyofauna, reproduction of pink salmon is concentrated in Terpeniya Bay. The data on the dynamics of the number of migrants and spawners are given. The size of the pass of pink salmon spawners in the rivers of Terpeniya Bay required for sustainable reproduction is estimated at 3.63–10.42 million individuals.