Year: 2021, Number: 2, Pages: 77-94
This work presents the results of remote monitoring one of the largest Baikal seal’s coastal rookeries on Lake Baikal. We determined animal population dynamics depending on the water level in the lake. For field observations we used a video camera that transmits data online. Video recording location was the coastal seal rookery on the Ushkany Islands Archipelago (Lake Baikal, Russia). We recorded single seals appearing in the rookery area a few days after floating ice disappeared in the northern part of the lake (in 2017 it was June 2, in 2018 it was May 28). Their total number in haul-outs on some days reached 100–130 in 2017 and more than 200 individuals in 2018. In June and July animals hauled-out almost every day. Since August, the intensity of coastal use decreased, but seals visited the coast until late autumn and in October, haul-outs could be more numerous than in September. Interannual differences in the number of animals during first haul-outs might have been due to variations in the ice regime of the lake (when the lake was completely free of ice), which affected the distribution of seals over the water area. Numbers of hauling-out animals also depended on water levels. When seals began approaching the rookeries, the water level was low; during the summer-autumn period of 2017 it changed insignificantly (+26 cm), while in 2018 water flooded many rookeries (+106 cm). Our study showed human disturbance to significantly impact the behavior of seals. Even in protected areas (Zabaikalsky National Park) seals were driven off their rookeries almost daily, often more than once. Animals left the shore for 4-6 hours, and often up to 1.5–2 days.