Winter Distribution of Salmon in Relation to Currents and Water Masses in the Northeastern Pacific Ocean and Migrations of Sockeye Salmon

Abstract

Abstract Studies of the distribution of Pacific salmon (genus Oncorhynchus) indicated that various species and age groups have an affinity for certain environmental features as exemplified by water characteristics. In the winter of 1967 in the northeastern Pacific Ocean, immature age .1 and .2 sockeye salmon, chum salmon, and coho salmon were caught primarily in the Oyashio Extension and Subarctic Current Areas; maturing age .2 and .3 sockeye salmon were primarily in the Alaskan Stream and in the Alaskan Gyre (Ridge and Oyashio Extension Areas). The hypothesis is offered that maturing Bristol Bay sockeye salmon remain in the Alaskan Stream and Gyre in winter. The data suggested that some of the immature Bristol Bay sockeye salmon that will mature the following year recirculate in the Alaskan Gyre in the summer and do not make an extensive east-west migration, although other immature Bristol Bay sockeye salmon are known to migrate far to the west during the summer.