Summer migration activity of the beluga whale Delphinapterus leucas in Dvina Bay, the White Sea

Abstract

Part of the beluga whale population overwinters in the White Sea every year, but active migrations start after the ice melts, in May–June. It is assumed that the whales distribute among the bays when they migrate along the Terskii Coast to the inner parts of the White Sea, Onega and Kandalaksha bays. The whales pene� trate to Dvina Bay along the Zimnii Coast. The whales may migrate to Mezen’ Bay also migrating along Ter� skii Coast, but they turn eastwards when passing the margin between Voronka and Gorlo. The outbound migration from the inner parts of the White Sea back to the Barents Sea in July and August usually occurs along the coasts of the Kanin Peninsula [3–6, 10, 11]. The maximal abundance of beluga whales is observed in July in Onega and Dvina bays, when the herds con� sisting of whales of different ages and both sexes join together. The total abundance of this species in the White Sea (summer period) varies from several dozens of hundreds up to 15 000 specimens [4, 12, 13].