Acoustic-trawl studies of the Coregonus migratorius (Georgi,1775) in the Selenga shallow water zone of Lake Baikal, 2023

Abstract

Study of peculiarities of distribution of aggregations and size-age structure of the Baikal omul feeding stock in the Selenga shallow water zone of Lake Baikal were studied using the hydroacoustic method in combination with control trawls. Comparative analysis of the results of 2023 with the data of 2015-2022 showed significant changes in the general character of distribution of the Baikal omul aggregations in the water area and depth. Standard length of fish from different shallow water zones ranged from 10 to 39 cm with a sample median of 17 cm. In terms of weight, individuals of 18-26 cm in length were dominant. A “length-age” equation allows making an operational assessment of age class abundance correlation based on the probability of assigning individuals of a certain length to them. It is shown that 3-5 years old fish form the basis of the biomass of feeding stock in the Selenga fishing zone. A significant proportion of young fish indicates that there is sufficient recruitment to increase the biomass of the Baikal omul stock in 5 years perspective.