鴨川湾におけるスナメリの移動

摘要

The finless porpoise is distributed around Japan. Although it is also observed frequently in the sea near Boso Peninsula, Chiba, there is limited information on this species. Between 1997 and 2008, we observed the movement of finless porpoises in the Bay of Kamogawa, Chiba, and they were often observed during the summer and autumn. The size of the schools that visited in those seasons was larger than that of the schools observed in other seasons. The finless porpoises visited the bay mainly in the morning, and they tended to swim away towards the east after an average of 20 min.