スケトウダラ太平洋系群および日本海北部系群の資源動態と変動要因

摘要

Changes in the stock and recruitment biomass of two walleye pollock stocks, Japanese Pa-cific stock and Japan Sea stock, were described. Catches and stock biomass were both decreasing in both stocks, especially in the Japan Sea stock. Considering the results of sea surface temperature as a main factor for the recruitment fluctuations, high recruitment was contributed to high temperatures in Japanese Pacific stock, and in contrast, low temperatures were the cause in the Japan Sea stock. In addition, some factors other than sea temperatures may have had some effect to recruitment fluctuations.