Behavior of Yukon River Chinook Salmon in the Bering Sea as Inferred from Archival Tag Data

摘要

Understanding the vulnerability of Chinook salmon to variability in climate and fishing mortality is complicated by a lack of information on migration and behavior. An archival tag placed on a Chinook salmon in the Bering Sea in 2002 was recovered in the Yukon River in 2004. During eight seasons the fish displayed a wide variety of behaviors. In summer, it was usually within the top 50 m. In the first winter it remained near 125 m, while in the second it remained within the top 50 m. Fall was a transition period between summer and winter, and in spring the fish underwent large (> 340 m) vertical movements. Temperatures experienced by the fish ranged from 1°C to 12°C. A comparison of sea surface temperatures and temperature profiles derived from tag data with oceanographic data indicated the fish was mostly in the central and southern Bering Sea Basin, with part of its second summer and final homeward migration on the eastern Bering Sea shelf. Data from another tag on a maturing Yukon River Chinook salmon indicated it moved directly from the Basin to the Yukon in three weeks. Neither fish spent substantial amounts of time in the area of groundfish fishery operations.