Long-term variations in abundance of Pacific herring (Clupea pallasi) in Hokkaido and Sakhalin related to changes in environmental conditions

Based on trends in sea surface temperature (SST) observed from 1914 to 1979 and reconstructed from 1782 to 1970 in the northern Japan Sea off the west coast of Hokkaido, this study demonstrates that very strong year-classes o f Pacific herring (Clupea pallasi) of the Hokkaido-Sakhalin stock have been produced during low to near-average SST periods whereas catches have been poor during high SST periods. Longterm SST and herring catch trends in this region appear to have been affected by large-scale atmospheric changes ove r the North Pacific. Variations in herring year-class strength or recruitme nt were related with variability of spring SST off the west coast of Hokkai do. Strong year-classes were produced in years (not all), when variance of monthly (April to May) mean SST anomaly was low, but there was no productio n of strong year-classes in years when variance was high. (C) 2001 Elsevier Science Ltd. All rights reserved.