Relationships between Alaskan salmon catch and North Pacific climate on interannual and interdecadal time scales

Using multivariate time series models, Alaska's statewide commercial catch of three salmon species during 1925-1994 is shown to be related to surface temperatures in particular large regions of the eastern North Pacific. Prev ious research has indicated that interdecadal changes in Alaskan catch leve ls are related to large-scale changes in the climate regime of the North Pa cific. The present work focuses on interannual variability by controlling f or climatic shifts in the mid-1940s and mid-1970s. For sockeye (Oncorhynchu s nerka) and chum (O. keta), relationships with temperature occur within a few months after ocean entry with warmer regional temperatures enhancing su rvival. For sockeye and pink salmon (O. gorbuscha), relationships with temp erature occur at the time and location of the return migration, suggesting that colder ocean temperatures may enhance spawning success or egg survival . In addition, the models show a significant positive relationship of chum catch to pink catch 2 years earlier, suggesting a common influence on smelt s of the two species. The results support the contention that climatic fact ors affecting the marine environment play a significant role in salmon prod uction on interannual, as well as interdecadal, time scales.