MIGRATION OF YELLOWTAIL IN RELATION TO INTRUSIONS OF WARM WATER FROM THE KUROSHIO

In the Kumano-nada and Enshu-nada Seas, warm water masses from the Kur oshio intrude into the coastal area depending on the paths type of the Kuroshio. Associated with the intrusions which occur with a period of 50 days from the Izu Peninsula when the Kuroshio takes the B-type pat h, yellowtail adults called buri migrate to the coastal area. However, the long time-lag between the intrusion and buri catch causes a negat ive relationship between the temperature and catch. The results sugges t that the buri school migrates westward after the water mass has diff used. Since there is a positive relationship between temperature and c atch associated with very rapid intrusions when the Kuroshio takes the C-type path, it is necessary to distinguish oceanographic phenomena i n order to understand the fish behavior in response to offshore oceani c changes. In addition, the seasonal horizontal temperature gradient s hould be considered when estimating the optimum temperature range for fish because the relative temperature change greatly affects fish migr ation rather than the optimum temperature.