Title Ocean distribution and migration of Japanese chum salmon
Authers Shigehiko URAWA
Keywords Japanese chum salmon, ocean migration, genetic stock identification, otolith mark
Citation Bull. Fish. Res. Agen. No.39, 9-19, 2015
Abstract
The migration route of Japanese chum salmon (Oncorhynchus keta) has been estimated using recent information on fish abundance, otolith marks and genetic stock identification (GSI) of mixtures sampled on the high seas. Japanese chum salmon globally shift their marine distribution depending on the life stage and season. Juvenile chum salmon leave from the coastal areas in the spring and early summer, and inhabit in the Okhotsk Sea during the summer and fall. With the decrease of surface seawater temperature (SST) in November, juveniles move to the western North Pacific Ocean, where they are distributed in a narrow area of SST 4-6℃ during the first winter. After the first wintering, young chum salmon (ocean age 1) migrate to the Bering Sea by the next summer for feeding. In the late fall, immature chum salmon move southeast to the Gulf of Alaska for their second wintering. They migrate between the summer feeding ground in the Bering Sea and the winter habitat in the Gulf of Alaska until they return to natal rivers in Japan through the Bering Sea for spawning. Intensive research on the survival mechanism of juvenile chum salmon migrating to the Okhotsk Sea and the long-term monitoring of salmon stocks in the major feeding waters in the Okhotsk Sea and Bering Sea are indispensable for the sustainable salmon fishery management in Japan.
URI http://www.fra.affrc.go.jp/bulletin/bull/bull39/39-03.pdf