PACIFIC SALMON PRODUCTION TRENDS IN RELATION TO CLIMATE

Pink (Oncorhynchus gorbuscha), chum (O. keta), and sockeye salmon (O. nerka) represent approximately 90% of the commercial catch of Pacific salmon taken each year by Canada, Japan, the United States, and Russia . Annual all-nation catches of the three species and of each species, from 1925 to 1989, exhibited long-term parallel trends. National catch es, in most cases, exhibited similar but weaker trends. The strong sim ilarity of the pattern of the all-nation pink, chum, and sockeye salmo n catches suggests that common events over a vast area affect the prod uction of salmon in the North Pacific Ocean. The climate over the nort hern North Pacific Ocean is dominated in the winter and spring by the Aleutian Low pressure system. The long-term pattern of the Aleutian Lo w pressure system corresponded to the trends in salmon catch, to copep od production, and to other climate indices, indicating that climate a nd the marine environment may play an important role in salmon product ion.