STATUS OF THE PACIFIC WALRUS POPULATION, 1950–19891

Authors


  • 1

    This paper is the result of a 30-yr study by Dr. F. H. Fay. He drafted much of the paper before he died on 9 June 1994. Dr. Fay was meticulous at record-keeping; the data and calculations reported here are archived at the Institute of Marine Science, University of Alaska Fairbanks, along with papers and reports cited here.

  • Many individuals and agencies in the United States and in Russia assisted in the long-term research reported here. Preparation of this paper depended on financial support arranged by J. R. Twiss (U.S. Marine Mammal Commission) and Gerald Garner (U.S. National Biological Service). Additional insights were gained from discussions with Russian colleagues, especially G. A. Fedoseev, V. N. Gol'tsev, V. N. Mineev, and N. I. Mymrin. Two anonymous reviewers provided comments on an earlier draft. Gay Sheffield produced Figure 1.

Abstract

The Pacific walrus (Odobenus rosmarus divergens) population is an important ecological and economic resource of the Bering Sea region. We describe population change, beginning with a low in 1950, through a high in about 1980, and ending in 1989. Estimates of abundance for the years after 1989 were not attempted due to the lack of harvest data and other population parameters. Selective hunting practices resulted in biased data regarding population composition and reproductive performance. Rates of reproduction had to be estimated from ovarian data, which indicated a dramatic drop in the 1980s. High harvests in the 1980s likely contributed to a decline in the population, but uncertainties as to accuracy of population estimates and other data raise reasonable doubts, especially with respect to the number of males, for which the most recent (1985) population estimate suggests a sharp decline. Past population estimates were revised upwards to compensate for walruses underwater and not seen in aerial surveys. The weaknesses in the available data make it clear that effective management of the population will require many improvements in collection of data regarding harvests, population structure, reproduction, and population trend.

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