The pelagic feeding ecology of the Short-tailed Shearwater Puffinus tenuirostris in the Subarctic Pacific Region

Abstract

Stomach contents from a total of 439 Short-tailed Shearwaters taken at 94 stations in the Okhotsk Sea, North Pacific Ocean and Bering Sea during the summer, 1970-1978, were examined in order to determine the food and feeding habits of this seabird.The diet for Short-tailed Shearwaters varied according to sea area. Overall it consisted mainly of small-sized organisms such as larval and juvenile fish and squid, euphausiids, amphipods, copepods, shrimp, and Thecosomata, all of which are usually abundant in the surface layer of the pelagic environment. The occurrence of the herbivorous copepod, Calanus cristatus (Copepodite V stage), in some stomach samples suggests that the Short-tailed Shearwater sometimes also depends upon zooplankton of lower trophic levels.Based on the results of this study the feeding biotope of the Short-tailed Shearwater, when wintering in the Subarctic Pacific Region, demonstrates high adaptability in prey and pelagic environment. These features enable this species to attain an immense population size in the Northern Hemisphere.