Features of biology of commercial fishes of the Small Aral Sea (Kazakhstan)

The purpose of the work was to assess the biological characteristics of the main commercial fish populations of the Small Aral Sea in 2022 and the changes that have occurred in them since 2013. The fish for the study were caught throughout the Small Aral in six fishing areas. According to the results of 2022, there were 15 commercial species in the ichthyofauna, of which bream, zander, roach and carp were the most numerous. The share of other fish in the research catches was from 0.5 to 5%. Compared to 2013, the species composition of the commercial part of the ichthyofauna has remained almost unchanged. Average sizes of most fish species for the period 2013-2022 also remained virtually unchanged. It should be noted only a slight grinding of bream and roach. The age composition of some fish has changed noticeably. The commercial population of carp, silver carp, wels and snakehead in 2022 is represented by older individuals than in 2013. In the populations of sabrefish and roach, on the contrary, younger fish predominate. Sex ratios in fish were studied depending on changes in water salinity in the Small Aral Sea. As a result, significant positive correlations were obtained for bream, silver carp, grass carp and zander. For rudd, on the contrary, a significant negative correlation was obtained.