Home – Home – Jornals – Geography and Natural Resources 2022 number 5S

The features of the influence of seasonal and interannual changes in the level regime of Lake Baikal on the populations of the main commercial fish species inhabiting the littoral zone of the northeastern coast which is the least exposed to the negative anthropogenic impact, are considered. Based on results of monitoring studies conducted during 1984-1990, it was determined that changes in water level of Lake Baikal and its tributaries have only a minor influence on the structure of the fish population in the littoral zone and biological characteristics of the main commercial fish species (black Baikal grayling and lenok) inhabiting this zone. The dominant role of black Baikal grayling in the ichthyocenosis at any water levels has been revealed. Lenok is a subdominant. Other commercial fish species (taimen, lake and river whitefish, pike, roach, dace, perch, and burbot) are not numerous and occur infrequently, mainly in pre-mouth sections of tributaries. It is concluded that one of the mechanisms of fish adaptation to the extreme changing conditions of the lake level regime is, undoubtedly, trophic adaptation aimed at consuming the most numerous and accessible food object. For the black Baikal grayling, they are unarmed small and medium-sized amphipod species and for lenok, they are stone and sand sculpins and large unarmed and armed amphipods. The most numerous food objects, such as imago of the Baikal caddis flies, are intensively consumed by all littoral fishes during their intensive emergence. This significantly reduces competitive relationships and contributes to better adaptation of fish to negative influences.