Abstract
The article presents the results of 2021 research on the bream (Abramis brama) population of the Kapchagay Reservoir and notes the changes that have occurred in its population compared to earlier studies. Modern sustainable use of natural biological resources presupposes the mandatory preservation of their natural reproduction, while taking into account the need to preserve each type of resource not only within its natural range, but also in each habitat. One of the valuable natural bioresources is the commercial ichthyofauna of inland waters. The Kapchagay Reservoir is one of the main fishery reservoirs in the country. The main share of the industrial catch in this reservoir falls on the bream (Abramis brama). Studies of the bream population of the Kapchagay Reservoir conducted in 2021 showed that the age structure of this species is represented by twelve age groups (from 1+ to 12+). At the same time, 4-year-old fish predominate,their share in the catches amounted to 22.03%. The main fishing load falls on fish older than five and six years, the share of which in the catches was 13.28% and 10.73%, respectively. Visualization of the spatial distribution data of bream in the Kapshagay Reservoir showed that despite the fact that bream is found throughout the water area in relatively large quantities, there is a seasonal accumulation in certain areas of the reservoir. The rejuvenation of the bream population in the Kapshagay Reservoir compared to the catch records of previous years indicates overfishing, which is due to its IUU fishing