1Department of Fisheries Resource Management, Tokyo University of Fisheries, Minato, Tokyo 108-8477, 2Hokkaido National Fisheries Research Institute, Kushiro, Hokkaido 085-0802, Japan
The relationships between water temperature and the fluctuations in walleye pollock catch in the northern waters of the Japan Sea were examined. We conducted correlation analysis and factor analysis of the data of catches over 30 years and water temperatures. The results were as follows: (1) The surface water temperature in the northern waters of the Japan Sea off Hokkaido had strong relationships with the walleye pollock catches harvested in the waters of the Japan Sea. (2) The catch harvested in year t showed highly negative correlation with the water temperatures of January, February and September in year t-τ(τ=3, 4, 5). It is considered that the water temperature influenced the reproduction of the fish and the fluctuations of stock abundance.