Abundance and distribution of the Ladoga ringed seals in anomaly warm winter 2020: results of the arial survey using drones

The aim of this research was to assess the abundance and distribution of the Ladoga ringed seals during anomaly warm winter 2020.The main method of the research was arial survey of the seals using drones. Taking into account complete absence of ice on the surface of the Ladoga Lake at the time of the survey (April-May, 2020) a new method for assessing the seals abundance was used that was based on the extrapolation of the seals density along the coast line using barrier model in R Statistic Software.As a result of the research, it was shown that during anomaly warm winter, in the absence of ice fields on the Ladoga Lake, the seals formed rookeries directly on the co0astline of remote islands and hardly accessible rocky inlets in the northern part of the Ladoga Lake. Total number of the seal population, estimated basing on the arial survey data was 5,680 individuals.Conclusion: The study showed that the islands, skerries and rocky inlets in the northern part of the Ladoga Lage act as a kind of refuge for the Ladoga ringed seal during anomaly warm ice-free winters. These environments provide the seals proper substrate suitable for bedding and shelter. Basing on the survey data, the population of the Ladoga seal in the northern part of the Ladoga Lake was amounted to 5,680 individuals which is close   to the estimates obtained for the entire Ladoga Lake in 2012–6.5 thousand individuals. Thus, the data of the 2020 air survey allow us to make a preliminary conclusion that the population of the Ladoga seal has not changed significantly over the past 8 years.