The Pacific Decadal Oscillation and Pacific Salmon Production

Retrospective analyses of Pacific Basin climate records highlight the existence of a pan-Pacific interdecadal climate oscillation. We find strong evidence for coherent patterns of interdecadal variability in Pacific winds, sea level pressures, and upper ocean temperatures. Collectively, the ocean-atmosphere pattern of variability has been labeled the “Pacific Decadal Oscillation”, or PDO. An index for the PDO has been developed from an empirical orthogonal function (EOF) analysis of north Pacific SST records dating back to 1900. An analysis of Pacific coast salmon catch records suggests that the dominant pattern of salmon production is driven by low-frequency climate variations associated with the PDO. The characteristics of this salmon production pattern of variability include a preferentially interdecadal time scale of variation that is coherent with our PDO index, and a north-south inverse production pattern in which Alaska stocks tend to be productive while those in the Pacific northwest are relatively unproductive (and vice versa).