Short period fluctuations in oceanographic and fishing conditions in the coastal area of Kumano-nada Sea.

Abstract

In order to study the detailed characteristics of fluctuations in oceanographic condition in the coastal area of Kumano-nada Sea, data of the temperature at set net stations in Mie Prefecture and direct current measurements curried out at Katada set net station were analyzed spatially and temporally. In addition to this study, focusing on a rapid temperature ascent observed in May 1984, the relationship between coastal and offshore oceanographic conditions was also discussed using data measured by a ferry boat and current meters.The temperature and current data in the coastal area of Kumano-nada Sea show a clear 20 days periodicity almost the same as a period of the Kuroshio's small scale meander. And temperature becomes higher with the intensified northeastward currents. In connection with this 20 days periodic fluctuations, there is an obvious relationship between catches of yellow-tail Seriola quinqueradiata and coastal oceanographic conditions in the particular distinct area obtained from a cross-correlation analysis for temperatures at set net stations. In these observations, we could obtain schematical transitions of warm water intrusion and it had clarified the about one week time lag of response for temperatures between offshore and inshore conditions which may be attributed to a continental slope.