Our knowledge of the feeding habits of the Pacific white-sided dolphin, Lagenorhynchus obliquidens, and the Dall's porpoise, Phocoenoides dalli, is based on examination of the stomach contents of stranded animals, animals accidentally taken in commercial fishing gear, those taken in the western Pacific commercial fishery, and animals that died during capture attempts. Of these only a few were normally feeding animals taken at sea, whose stomach contents were thoroughly examined. Fished and squids previously identified from stomachs of dolphins and porpoises by various investigators are listed in Table 1.
This paper documents the stomach contents of 44 Pacific white-sided dolphin and 9 Dall's porpoise collected at sea off California and Washington. All animals were collected by the authors during pelagic fur seal studies with the exception of three dolphins which were collected by a staff biologist during whale research voyages off California. Comparisons of stomach contents are made between the Pacific white-sided dolphins, Dall's porpoise, and northern fur seal, Callorhinus ursinus, collected near the same locations and usually on the same day. Mention of the dolphin, porpoise , and seal in this paper refers to the above-named species unless noted otherwise.
