Summer coastal rookeries and perspectives of the Baikal seal (Pusa sibirica) population in the conditions of the global warming

E. A. Petrov,A. B. Kupchinsky,V. A. Fialkov

doi:10.15421/012149

E. A. Petrov, A. B. Kupchinsky + Show 1 more

Open Access

https://doi.org/10.15421/012149

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Abstract

Based on the secondary literature, a retrospective characterization of the climate in the Baikal region, starting from the end of the Pleistocene, is given. According to satellite monitoring data, the characteristics of the ice regime of the Lake Baikal in the conditions of climate warming are presented. Moreover, we briefly discuss the impact of climate change on the ecology and biology of the Baikal seal (Pusa sibirica Gm.). Using video materials obtained online at one of the main island coastal rookeries of seals (on the island of Tonkyi, the archipelago of the Ushkany Islands, Lake Baikal) in 2011–2017, the dependence of the number of seals hauled out on the lake level and the peculiarities of the fishing regime was determined (the survey was conducted from May–June to October). A direct relationship was determined between the relative number of animals that had a moulting delay and the ice regime of a given year: the longer the floating ice in the northern part of Lake Baikal remained, the more numerous were the first approaches of seals to the studied rookery and the greater was the proportion of moulting individuals. It is reasonable to assume that the main reason for the Baikal seal to come ashore is not prolongued moulting time, but a physiological need for sunlight, which has a healing effect on the body of animals that lack solar radiation in winter. In general, climate warming has a negative impact on the state of the Baikal seal population. The available paleoclimatic reconstructions of the Holocene indicate that the population of the Baikal seal has experienced a lot of climate changes in its history. Nevertheless, if the current trends of climatic changes persist until the end of the 21st century, the ecology and biology of the seal will drastically change (up to the beginning of terrestrial reproduction), and the population will significantly decrease. However, the Baikal seal as a species would remain.

Highlights

Lake Baikal is inhabited by one seal species – the Baikal seal (Pusa sibirica Gm.), and it is the only mammal in the ecosystem the population of which completes the lake's food chain
The individual features of the Baikal seal are clearly shown at the birth of the pup or during annual moults the annual molting period, which normally occurs on floating ice (Ivanov, 1982)
The Baikal seal population has been living for many years under climate warming, and people hope that it can adapt to change since the climate change is not catastrophic

Summary

Introduction

Lake Baikal is inhabited by one seal species – the Baikal seal (Pusa sibirica Gm.), and it is the only mammal in the ecosystem the population of which completes the lake's food chain. The status of the seal population indicates the well-being of the entire ecosystem or at least its pelagic part. Most of the seals’ life (which is generally pelagic) is connected with ice due to its northern roots – the ancestors of the Baikal seal came to the freshwater Baikal, located in the center of Asia, most likely from the north in the Ice Age (Numachi et al, 1994; Sasakiet al., 2003). The seals disperse along the lake when there is no floating ice. The seals disperse along the lake when there is no floating ice To feed, they explore the water column to 300–400 m depth. They explore the water column to 300–400 m depth Those animals that were unable to moult on the floating ice cannot finish moulting (Petrov, 2009)

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