The Baikal seal (Pusa sibirica Gm.) lives in a freshwater, deep-water lake. Baikal, located almost in the center of the Asian continent, is a pagetogetic species of true seals. During the ice-free period, a significant part of the population uses the shore as a temporary habitat, mainly due to the need to complete the seasonal molt on an adequate substrate. The goal of the work was to establish the pattern of use by the Baikal seal of coastal rookeries located on the Malye Ushkany Islands in the summer-autumn period. The materials were collected in 2022 during August–November using stationary camera traps Seelock S308 Hyperlink (technical specifications on the website https://seelock.r) installed on each of the three small islands of the Ushkany Islands archipelago (two per island). The traps were installed by employees of the Transbaikal National Park (FSBI “Zapovednoye Podlemorye”). The traps operated in automatic mode (recording was carried out every 3–4 hours every day), and 4518 still images (volume 12.07 GB) were analyzed. In all still images, the number of Baikal seals lying on land (on the beach and on rocks lying near the coast) and swimming in the water was counted. Based on the data obtained, the dynamics of the number of animals in the rookery areas is shown. It has been established that the development of rookery sites on different islands occurs simultaneously (at the same or very close dates) on three islands. The number of animals in a rookery is determined by the physical parameters of the rookery areas (size, substrate, water level) and depends on the number of seals in wandering groups. No mass migrations of seals from one island to another have been recorded. A clear daily dynamics of the number of Baikal seals in the rookeries has not been established, and in different rookery areas it manifested itself differently (6 options were identified). In autumn, a greater dependence of the frequency of use of rookeries on hydrometeorological conditions, as well as on anthropogenic disturbance factors, was noted. In conditions of a reduction in the flow of tourists visiting one of the rookeries on the island. Long for recreational purposes, in autumn on two of the three islands the factor of disturbance from the point of view of its influence on the dynamics of visiting the Baikal seal rookeries is assessed as minimal.

Ovdin Mikhail Evgenievich, Director, Zapovednoe Podlemorye (Reserved Podlemorye), 1, Lenin st., Ust-Barguzin settl., 671624, Russian Federation, e-mail: ovdin@pdmr.ru

Petrov Evgeniy Apollonovich, Doctor of Sciences (Biology), Chief Research Scientist, Baikal Museum SB RAS, 1, Academicheskaya st., Listvyanka, 664520, Russian Federation, e-mail: evgen-p@yandex.ru

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