Changes in the Numbers of Cetaceans near the Pribilof Islands, Bering Sea, between 1975-78 and 1987-89

Lariann Baretta,George L Hunt Jr

doi:10.14430/arctic1304

Abstract

We compared the number of cetaceans seen during surveys of seabird distribution in the vicinity of the Pribilof Islands, Bering Sea, during two periods, 1975-78 (3867 km surveyed) and 1987-89 (6101 km surveyed). During the 1980s, we saw increased numbers of fin whales (Balaenoptera physalus) (0 to 66 individuals), minke whales (B. acutorostrata) (3 to 38 individuals), humpback whales (Megaptera novaeangliae) (0 to 24 individuals), killer whales (Orcinus orca) (5 to 58 individuals), and Dall's porpoises (Phocoenoides dalli) (101 to 241 individuals). It could not be determined whether these changes reflected changes in the numbers of these species in the Bering Sea, or simply local changes in their foraging or distribution patterns. Fin, humpback and minke whales were seen foraging in the vicinity of large flocks of birds that were eating euphausiids (Thysanoessa raschii and T. inermis).Key words: Fin whale, minke whale, humpback whale, killer whale, Dall’s porpoise, Balaenoptera physalus, Balaenoptera acutorostrata, Megaptera novaeangliae, Orcinus orca, Phocoenoides dalli, Bering Sea, whale foraging

Highlights

The distribution and abundance ofcetaceans in the southeastern Bering Sea have been surveyed in recent years from ships and from the air (e.g., Frost et al, 1982; Leatherwood et al, 1983; Brueggeman et al, 1987)
We compare observations of cetaceans near the Pribilof Islands between 1975 and 1978 with those made between 1987 and 1989, and we interpret our observations in light of past studies of the distribution and abundance of these species in the southeastern Bering Sea
Observations of marine mammals were recorded in the vicinity of the Pribilof Islands on six cruises between 1975 and Department of Ecology and Evolutionary Biology, University of California, Irvine, California 92717

Summary

Introduction

The distribution and abundance ofcetaceans in the southeastern Bering Sea have been surveyed in recent years from ships and from the air (e.g., Frost et al, 1982; Leatherwood et al, 1983; Brueggeman et al, 1987). A few surveys have resulted in reports on the distribution and abundance of species near the Pribilof Islands (Frost et al, 1982; Leatherwood et al, 1983).

Results

Conclusion