Marine Mammal Sci (1998)

DOI: 10.1111/j.1748-7692.1998.tb00695.x


(…) It has been hypothesized that Dall’s porpoises forage mostly at night or at dawn, because porpoises taken in the morning tended to have a larger amount of food remains in their stomachs (Stroud et al. 1981, Miyazaki et al. 1988). Mori and Kasuya (1991), however, examined stomach contents of Dall’s porpoises from the western North Pacific and the Okhotsk Sea and found distinct differences in diurnal occurrence patterns between these two areas. They suggested that Dall’s porpoises seem to alter their feeding time according to the availability of prey species. We report here the results of observations that support this hypothesis. (…)