Stock Origins of Chinook Salmon in Incidental Catches by Groundfish Fisheries in the Eastern Bering Sea, 1997-1999

摘要

The effect on western Alaska chinook salmon (Oncorhynchus tshawytscha) of incidental catches by commercial groundfish fisheries has been a major concern since 1977, when the U.S. National Marine Fisheries Service (NMFS) began to monitor and estimate salmon bycatch by groundfish vessels operating in the U.S. Exclusive Economic Zone (EEZ; Berger 2003). Most (> 99%) of the chinook salmon bycatch is taken by the walleye pollock (Theragra chalcogramma) trawl fisheries operating in areas with bottom depths of 100 m to 200 m, and high bycatch rates can occur in any location throughout the Bering Sea and Aleutian Islands (BSAI) area (Witherell et al. 2002). Myers and Rogers (1988) used scale pattern analysis to estimate the age, regional stock composition, and interceptions of western Alaska chinook salmon in incidental catches by foreign and joint-venture groundfish fisheries operating in the BSAI area of the U.S. EEZ in 1979-1982.