ニホンウナギ資源の変動特性

摘要

Spawning ground of the Japanese eel is located in the North Equatorial Current region, west of Mariana Islands. After passive larval transport, they migrate into coastal regions of East Asian coun-tries. For the larval transport, bifurcation of the North Equatorial Current into the Kuroshio and the Mindanao Current is a very important factor because the north-south movement of the bifurcation loca-tion is influenced by presence of El Nino event. In fact, amount of larval catch significantly decreases when El Nino occurs. However, recent decreases of glass eel and adult eel catch would be caused by impact of human beings. For further understandings of stock abundance fluctuation in the Japanese eel stock, accumulation of statistical data set is necessary not only in Japan but also any other countries in East Asia.