This summer, with the support of the Lake Baikal Foundation, scientists of the A.N. Severtsov Institute for Problems of Ecology and Evolution conducted research of the Baikal seal on the Ushkan Islands. A.N. Severtsov Institute for Problems of Ecology and Evolution conducted research of the Baikal seal on the Ushkan Islands. The scientists on this expedition were tasked with counting numbers, collecting biological material for research and assessing the impact of tourists on the animals. Previously, some data on the change in behavior of seals at the appearance of people were collected, but the information is fragmentary, so this year the research was expanded.
Walking surveys were conducted twice a day at 11 observation points
The network of observation points along the route along Tonky Island was established during the expedition 4 years ago. All points were determined in such a way that the observation sites did not overlap each other when covering the northern coast as much as possible. In order not to frighten the seals, the surveyors moved at a distance of 5 to 50 m from the water’s edge.
Binoculars and cameras with a long lens were used for observation, which made it possible to accurately count the number of individuals in a certain area without disturbing the animals. To maximize the representativeness of the sample, the surveys were conducted twice a day, with each observation period lasting from 30 minutes to 1 hour, during which time the scientists noted the number of underexposed, injured or sick individuals and, if possible, recorded the sex of the animals. A total of 39 surveys and more than 5,000 photographs were taken, with the most seals recorded at any one time (384 individuals) on July 21.
A quadrocopter was used for better coverage of the area
Animals roost not only on Tonky Island, but also on other parts of the Ushkanyi Islands archipelago, so the use of a quadrocopter significantly expanded the possibilities of counting. This time aerial surveys were conducted on the islands of Tonky and Kruglyy. There are always inaccuracies in land-based surveys because it is impossible to visually capture animals that are in the water. Comparison of shore-based counts and survey data allows us to estimate the percentage of seals not counted during foot surveys.
The quadrocopter allowed to obtain a large amount of video material from the haulouts, however, to avoid disturbance among seals, the flight was conducted at a height of 60 to 120 meters. A total of 48 videos with a total duration of more than 4.5 hours were obtained from aerial surveys over the islands of Tonky, Dolgiy and Kruglyy.
Tourist groups as one of the factors influencing seal behavior
To assess the influence of tourist groups on seal behavior, an observation point was also organized at the observation platform. Behavioral surveys were conducted daily for 6 hours. Every 10 minutes the animals were photographed in the den and the following indicators were recorded:
- presence of tourists at the site and their number;
- people’s behavior: how they talk, gesticulate, and where they are;
- noise level;
- weather conditions.
Natural phenomena sometimes had a stronger effect on seal behavior than the presence of people – for example, strong thunderclaps or the sudden appearance of large birds could also scare seals away from their den.
In the case of a mass descent of animals, the time and the supposed cause were noted, and their behavior was recorded in 5-minute intervals during the next 20 minutes. The materials obtained will allow us to determine the rate of recovery and behavioral changes of seals after scaring for different reasons.
Samples of various tissues and materials were taken for further research
An important part of the expedition was sampling for laboratory research. During the surveys, the shoreline of Tonky Island was surveyed for dead animals, and scientists had to overcome steep banks and slopes to reach them. A total of 4 dead seals were found during the expedition.
Upon discovery, the location, sex, age and basic parameters were noted in the protocol: total body length, tail length and thorax girth. To determine age in seals, the method of counting the number of complete segments on the animal’s claws is used – the growth phase of such segments coincides with the phase of hair change, which occurs once a year.
The scientists selected the following materials:
- muscle tissue samples – for genetic studies;
- hair and vibrissae – for hormonal and toxicological studies;
- claws – for hormonal studies;
- teeth/skull – for morphologic studies;
- fat samples – for fatty acid composition studies.
The hair and vibrissae will also be examined for mercury.
The data obtained will allow determining the factors affecting the number of animals and the current status of the population
Currently, all the materials received from the expedition are being processed. It takes a lot of time to count animals using video footage obtained using quadrocopters. The data obtained during the foot surveys and aerial surveys will make it possible to estimate the number of seals on Tonky, Dolgiy and Kruglyy islands in 2024, compare the results of this year’s survey with previous years, assess inter-annual population dynamics and better understand the environmental factors affecting the number of animals in the archipelago. Behavioral work carried out on Tonky Island will allow to determine the degree of impact of tourists on the behavior of Baikal seals at the deposit, and analysis of samples collected from dead animals – the physiological state of the dead individuals.
Also during the fall, behavioral surveys conducted at the largest seal den will be analyzed. All collected photo and video material will be analyzed and the behavior of each seal at the deposit will be evaluated on a specially developed scale. This is painstaking work that requires a lot of time and attention to detail.
The project was made possible thanks to the support of Siberian Wellness, the corporate trustee of the World Around You Foundation.