Summary distribution, season migration and comparative number of gray whales (Eschrichtius robustus Linnaeus, 1758) Kalifornia-Chukchi Sea population in coastal waters of Chukotka Peninsula
The paper presents the data resulting from shore based observation of distribution and migrations of gray whale in waters adjacent to the Chukotka Peninsula. The data cited indicate that in cold year, take place summer 1994 and 1998, with maximum extend ice edges in the region of the Chukchi Sea, the feeding period of gray whales in western part of Chukchi Sea was 3,5 month and in south part 4 month. In typical year, with minimum extend of ice edge, gray whales stay feeding in Chukchi Sea 5 and 6,5 month accordingly. Besides, in cold year floating ice blocked 2/3 feeding fields in northern and western part of Chukchi Sea, eastern part of East Siberian Sea, Longa Strait. High incidence of gray whale deaths in 1998/1999 one can explain by combination several factors : — overfill of feeding fields in connection with uncommon high population size of gray whale, cover up by ice 2/3 feeding fields, shortening of feeding period. In prevalent conditions gray whale not have possibilities accumulate enough energetic resources for winter time.