Possible Causes and Effects of Shifts in Trends of Abundance in Pink Salmon of Kunashir Island, a Population near the Southern Limit of Its Range in Asia

摘要

The results of monitoring pink salmon (Oncorhynchus gorbuscha) spawning in the rivers of Kunashir Island are presented. The abundance of this small stock is shown to be related to its spawning location which is close to the southernmost limit of spawning for this species. Long-term changes in the number of spawners and body size are similar to those for other larger pink salmon stocks in the Sakhalin-Kuril region. These similarities suggest that factors related to habitat changes play an important role in pink salmon stock dynamics.