Author(s): Chan-Su Yang; Hitoshi Tanaka; Masaki Sawamoto; Kimio Hanawa
Linked Author(s): Hitoshi Tanaka
Keywords: Sea temperature; Upwelling; Chlorophyll a; Kuroshio; Abnormal catch of fish
Abstract: A biological and physical study of a western boundary current flow over variable topography is presented, with the investigation of abnormal catch of fish around sea area of Soma in June 1999. In order to analysis the changes of water mass due to the offshore current, time series of vertical distribution of chlorophyll-a, dissolved oxygen and nutrient concentration (nitrogen, phosphorus), wind vector and satellite images (AVHRR/SST, NASA/SeaWiFS, LANDSAT/TM) are used from 1999 to 2000. The results indicate that the year-to-year variation of the offshore is very high and the 1999's condition is distinct with the 2000. Chlorophyll-a imagery and wind data reveal that the coastal region around the bay seems apparently to be not affected directly by offshore condition. Nevertheless, it is found that the bottom Ekman transport could cause the abnormal catch phenomenon of fish through enhanced advection over deep depths since the Kuroshio exceptionally exists off Soma.