抄録
Understanding the feeding habits of toothed whales is important in studies of cetacean ecology. The techniques of stomach content analysis have become more refined, and it is now possible to identify a lots of fishes and cephalopods using hard parts such as otoliths and beaks. These hard parts can also provide estimations of the body sizes of several hundred prey species. The prey selectivity of toothed whales has been summarily dismissed as being “opportunistic” and there has been little discussion about the mechanisms of prey switching. Recent detailed information on prey items has enabled researchers to consider prey selectivity when data of prey abundance are available. The detection of selection criteria may be an interesting topic in future studies concerning behavioral ecology. The ecological importance of cetaceans has been considered recently, and their prey consumption has been discussed as a matter of concern about competition with fisheries. Some toothed whales in coastal areas consume many prey species that are commercially caught. However, the competitive status may not only depend on the overlapping of prey, but also on the prey abundance and the ecological response of prey to predation and harvesting pressures.
