ИСТИНА

The Kuril Islands is a 1000 m long island chain that border Kamchatka peninsula in the north and Japan in the south. The Islands are known as an important feeding area for sperm whales, but no recent analysis of sperm whale distribution and area usage in this region has been published since whaling era. We conducted a survey along the Kuril Islands in August 2016 on board of 10m yacht and estimated the distribution of sperm whales. We found that the distribution of sperm whales was very irregular: in some areas the density was very high, while in others the whales were absent. We analyzed the dependence of whale density from different factors. We found that the whales were the most abundant in straits between the islands, probably because the strong tidal currents provide high productivity in these areas. The depth was another important factor that predicted the whale distribution. The results of this study can be used to determine the critical habitats of sperm whales in the Kuril Islands. However, more surveys are needed to estimate the variability in whale distribution in different seasons of the year and in different years.