On the relationship between interannual baroclinic waves and fish populations in the northeast Pacific

Abstract

AbstractFrom the cross-spectral analysis of 40–80 years of coastal sea level, sea surface temperature, and salinity data in the Northeast Pacific, we found coherent signals at frequencies of 0.09, 0.17–0.20, 0.33, and 0.43 cycles per year (corresponding to periods of 11, 5–6, 3, and 2.3 years). The strong 5–6 year oscillation, besides appearing in the sea level cross-spectrum, was manifested as a sea level-temperature oscillation near Vancouver Island, and as a sea level-salinity oscillation farther north. This signal was found to propagate northward, with a phase speed roughly comparable to that of a coastally trapped baroclinic Kelvin wave. The 3-year oscillation, which appeared to be cut off at higher latitudes, could be due to a westward propagating baroclinic Rossby wave.The relationship between these signals, which we interpret as baroclinic waves, and fish populations was then investigated. Cross-spectral analyses of the annual sockeye salmon (Oncorhynchus nerka) catch and herring (Clupea pallasii)...