Home – Home – Jornals – Geography and Natural Resources 2026 number 1

The characteristic features of distribution and behavior of the Baikal omul were studied for the first time using static hydroacoustic recording from the ice cover of Lake Baikal in the Selenga shallows, as well as in the adjacent deep-water area near the villages of Buguldeika and Bolshie Koty. The analysis of acoustic data on changes in fish aggregation density made it possible to assess their distribution and migration patterns. At the “Selenga” station, fish schools were observed moving at the same depths throughout 24 hours, while at the “Buguldeika” and “Bolshie Koty” stations, individuals aggregated into small groups at depths of 100-200 and 250-350 m, depending on the time of day. The reconstructed fish size composition from acoustic data based on the target strength of individual fish made it possible to determine the characteristics of their migrations at different stations. At the “Selenga” station, a high proportion of fish with a standard length of up to 17 cm was detected, indicating the presence of juvenile fish from the spawning river. In contrast, at the “Buguldeika” and “Bolshie Koty” stations, predominantly individuals with a standard length (SL) of 20-38 cm were recorded, which indicates the migration of fish over two years old from the underwater slope zone of the Selenga shallows to the mesopelagic zone. The study results demonstrated the fundamental feasibility of monitoring the distribution, migration patterns, and formation of the size composition of fish using the hydroacoustic method in static mode during the winter period. This opens new perspectives for studying the seasonal fish behavior and helps to better understand their ecology and interrelations in the natural environment.