Northeastern coast of Lake Baikal as a habitat of baikal seal <i>Pusa sibirica</i> in the summer period

Abstract

Filling of the rookeries of baikal seal Pusa sibirica on the northeastern coast of Lake Baikal is surveyed instrumentally for the first time within the boundaries of protected area. The main coastal haulouts of the species are located in this area, so all places suitable by their lithological parameters for the seals rookeries were examined to assess intensity of their use in modern conditions of anthropogenic impact. In total, ≈ 246 km of the coastline were traced, including 170 km surveyed with unmanned aerial vehicle DJI (in 317 minutes) and visual observations on the rest of the coast with binoculars and ground photo- and video-recording. Only 9 % of the surveyed coastline (> 21 km) is suitable for rookeries, located mainly in the northern part of the area. Unfavorable lithological properties (sands, sandy pebbles, small stones, rocks) prevail on the other part of the coast, though many places (usually big boulders) are available for small rookeries there, too. Currently all these places are almost never used by seals, except of short, sporadic haulouts, mainly in June, immediately after complete disappearance of the floating ice. The main reason why the animals leave their traditional rookeries in this area in July-August is an intensive anthropogenic load, in particular at the places where the largest rookeries existed previously, as the bays Frolikha, Ayaya, Khakusy, capes Khaman-Kit, Pongonye, and some others. The leaving of rookeries contradicts to increasing needs of seals for a solid substrate to complete their molt in conditions of climate warming. Possibly, the threat of losing the northeastern coast as a summer habitat for a significant part of the baikal seal population is underestimated.