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

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.

1. Baimukanov, M.T., Zhdanko, L.A., Baimukanov, T.T., Dauenev, E.S., Ryskulov, S.E., and Baimukanova, A.M., A method for accounting and identifying the linear sizesof Caspian seals (Pusa caspica) on rookeries using multicopters, Zool. Zh., 2020, vol. 99, no 2, pp. 215–222. doi 10.31857/S0044513 420020038

2. Vitkovsky, N., Notes on the issue of the Baikal seal, Izvestiya Vostochno-Sibirskogo otdela Imperatorskogo Russkogo Geograficheskogo obshchestva, 1890, vol. 21, no. 3, pp. 33–48.

3. Ivanov, K.M., Kupchinsky, A.B., Ovdin, M.Y., Petrov, Y.A., Syrovatsky, A.A., and Shabanov, D.Y., Experience in application of UAV in ecological studies of the baikal seal (Pusa sibirica Gm.) population at the beginning of shore rookeries formation, Mezhdunar. nauch.-issled. Zhurn., 2022, no. 8(122), pp. 1‒12. doi 10.23670/IRJ.2022.122.106

4. Ivanov, M.K., Skin and hair cover of the Baikal seal, in Morfo-fiziologicheskiye i ekologicheskiye issledovaniya baykal’skoy nerpy (Morphological and ecological studies of the Baikal seal), Novosibirsk: Nauka, 1982, pp. 20–39.

5. Ivanov, T.M., On Baikal seal Phoca sibirica Gmelin, its biology and fishing, Izv. biol.-geogr. Nauchno-Issled. Inst. pri Vostochnosib. Gos. Univ., 1938, vol. 8, no. 1–2, pp. 5–119.

6. Katin, I.O. and Nesterenko, V.A., Remote account of spotted seals on haulout sites of RimskyKorsakov archipelago (Peter the Great Bay) using drones, Biota and environment of natural areas, 2021, no. 1, pp. 72–81. doi 10.37102/2782-1978_2021_1_6

7. Pastukhov, V.D., Nerpa Baykala. Biologicheskiye osnovy ratsional’nogo ispol’zovaniya i okhrany resursov (Baikal seal. Biological foundations of rational use and protection of resources), Novosibirsk: Nauka, Sibirskaya izdatel’skaya firma, 1993.

8. Pastukhov, V.D., Level regime and population of the Baikal seal, in Limnologiya pribrezhnosorovoy zony Baykala, Novosibirsk: SO Nauka, 1977, pp. 289–299.

9. Petrov, E.A., Current distribution of Baikal Seal Pusa sibirica (Pinnipedia, Phocidae), Zool. Zh., 1997, vol. 76, no. 10. pp. 1208–1209.

10. Petrov, E.A. and Kupchinsky, A.B., Extended molting against the background of climate warming is the main reason for the emergence of the Baikal seal (Pusa sibirica, Pinnipedia) to coastal rookeries, Zool. Zh., 2023, vol. 102, no. 2, pp. 201–214. doi 10.31857/S0044513423010087

11. Petrov, E.A., Kupchinsky, A.B., and Fialkov, V.A., On the importance of coastal rookeries in the life of Baikal Seals (Pusa sibirica Gm.) in warming climate conditions, Mezhdunar. nauch.-issled. Zhurnal, 2021, no. 3(105), part 2, pp. 42‒47. doi 10.23670/IRJ.2021.105.3.032

12. Spravochnik po litologii (Handbook of lithology), Vassoevich, N.V., Librovich, V.L., Logvinenko, N.V., Marchenko, V.I., eds, Moscow: Nedra, 1983.

13. Shibanova, P.Yu., Ilyina, P.O., Glazova, T.D., Glazov, D.M., Solovyova, M.A., Razuvaev, A.E., and Rozhnov, V.V., First experience of drone usage to frequently estimate the abundance of the Baikal seal (Pusa sibirica, Gmelin, 1788) population at summer haulouts on the Ushkany islands, in Sb. Tezisov 11-y Mezhdunar. konf. “Morskiye mlekopitayushchiye Golarktiki” (Proc. 11th Int. Conf. “Marine Mammals of the Holarctic”), Moscow, 2021, p. 109.

14. Beltran, R.S., Burns, J.M., and Breed, G.A., Convergence of biannual moulting strategies across birds and mammals, Proc. R. Soc., 2018, B 285:20180318. doi 10.1098/rspb.2018.0318

15. Niemi, M., Nykanen, M., Biard, V., Kurkilahti, M., and Kunnasranta, M., Molting phenology of a lacustrine ringed seal, Pusa hispida saimensis, Ecology and Evolution, 2022, 12:e9248. doi 10.1002/ece3.9248

16. Petrov, E.A., Kupchinsky, A.B., Fialkov, V.A., and Badardinov, A.A., The Importance of Hauling Grounds in the Life of the Baikal Seals (Pusa sibirica Gmelin 1788, Pinnipedia): 1.Review, Biology Bulletin, 2021, vol. 48, no. 9, pp. 1704–1714. doi 10.1134/S1062359021090181

17. Petrov, E.A., Kupchinsky, A.B., Fialkov, V.A., and Badardinov, A.A., The Importance of Coastal Hauling Grounds in the Life of the Baikal Seal (Pusa sibirica Gmelin 1788, Pinnipedia): 3. Utilization of Coastal Hauling Grounds by the Baikal Seal on Tonkii Island (Tonkii Ushkan Islet), Ushkan Islands, Lake Baikal, Based on Video Observations, Biology Bulletin, 2022, vol. 49, no. 7, pp. 975–991. doi 10.1134/S1062359022070159 www.rushydro.ru. Cited January, 2023.

18. Lotsiya i fiziko-geograficheskiy ocherk ozera Baykal (Pilot and physical-geographical sketch of Lake Baikal), St. Petersburg: Association of R. Golike and A. Vilborg, 1908.

19. Atlas ozera Baykal № 65064. Pribrezhnaya chast’ (Atlas of Lake Baikal No. 65064. Coastal part), St. Petersburg: GUNIO MO RF, 2001.