On migrations and seasonal distribution of the beluga whales Delphinapterus leucas in the Chukchi and East Siberian Seas

The results of aerial observations of belugas (Delphinapterus leucas Pall.) in the western Chukchi and eastern East Siberian Seas for the period from April to November were generalized based on Russian literature and unpublished data. The data of observations in the littoral zones of Wrangel Island and Chukotka carried out in 1985 to 2001 are submitted. The author's data, those of native hunters, as well as the published results showed the use of different parts of the seas by beluga, its migrations in the eastern Arctic, and the degree of separating the populations of belugas of the Chukchi and East Siberian Seas. The data obtained attest that the fish does not winter regularly in these seas, and there are no reasons for separation of local Chukchi and Bering populations. A gap in the species range is suggested to take place in the western part of the East Siberian Sea.