Abstract
Among damages to fisheries by water pollution, appearance of fish with offensive odor has created the social problems by the loss of their commercial value. Since 1962, fish with offensive odor have appeared in Nagara River. Such foulsmelling fish are caught along about 20 km of this river in Hashima area from Chusetsu Bridge, where Arata River and Sakai River flow into Nagara River, and about 8 km from Ise Bridge to Nagashima area. Such offensive odor was found in the fish inhabiting the bottom of the river and those living in the river for a long period. These fish were found to live in the polluted basin and ingested a kind of substance with an offensive odor, which was considered to be one of the factors for the appearance of fish with offensive odor.
