BIOLOGIYA MORYA, 2014, Vol. 40, No. 1, pp. 32-37

The influence of ice conditions on terrestrial haulouts of the Pacific walrus Odobenus rosmarus divergens Illiger, 1815 in the Gulf of Anadyr, Bering Sea

© 2014 N. V. Kryukova¹, A. A. Kochnev², A. A. Pereverzev³

¹Russian Federal Research Institute of Fisheries and Oceanography, Moscow 107140;
²Pacific Fisheries Research Center, Chukotka Branch, Anadyr 689000;
³Pacific Fisheries Research Center, Vladivostok 690091

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The boundaries of the area of appropriate depths for feeding of Pacific walrus were determined. Based on the ice maps for the period of 1997-2011, the multiyear dynamics of ice breakup and formation in the Gulf of Anadyr (Bering Sea) were analyzed. There was a tendency towards a reduction in the ice cover period in the Gulf of Anadyr, especially during 2007-2011. In 2008, the number and duration of stay of walruses at terrestrial haulout sites in the Island of Meeskyn Spit and Retkyn Spit continued to decrease. Walruses also used other haulouts located in the Gulf of Anadyr at Cape Gek and Cape Retkyn. The age and sex structure of walrus herd changed: the proportions of adult males and young animals decreased, while the proportion of females with calves increased.

Key words: Pacific walrus, pinnipeds, Bering Sea, Gulf of Anadyr, ice, dynamics, abundance, age and sex structure.