West coast of Lake Baikal as a habitat for baikal seal Pusa sibirica in summer season

Abstract

Using of the known rookeries on the western coast of Lake Baikal (including Olkhon Island and the isles in the Small Sea Strait) by baikal seal Pusa sibirica is assessed for modern conditions of anthropogenic pressure. All locations with geomorphological and lithological patterns suitable for rookeries are examined. For these purposes, the data from scientific literature were reviewed and the shores were researched visually with binoculars (from research boats) and from small UAVs, with particular attention to the historically known rookeries. Many new locations potentially suitable for haulouts and rookeries were found. However, the disturbance factor is significant for using these locations by seals — the most of known rookeries are visited sporadically by few seals in the short time between the floating ice disappearance and the beginning of the tourist high season. These rookeries were considered as «endangered» ones. When there is an urgent need (as in early summer 2020), seals come ashore in many locations, particularly on Olkhon Island, but don’t form new (not existed previously) rookeries. The threat of loss of the coast as a summer habitat for a significant part of the baikal seal population is possibly underestimated.