RESOURCE POTENTIAL OF SMALL RIVERS OF THE BALKHASH BASIN (CENTRAL ASIA, REPUBLIC OF KAZAKHSTAN)

The fall of fish catches is observed worldwide during last decades. The amount of fish caught lags behind the needs of the population. 2012–2021 we made an investigation of diversity of fish in catches in 14 small rivers of the Balkhash basin. The variety of fish caught was studied in connection with the remoteness of the rivers from large cities, the degree of protection, the maximum water temperature in summer, the content of ammonium ions and nitrates. The diversity of native fish in catches increases with distance from cities and the presence of protected sections of rivers.The main fish species caught were native naked osman Gymnodiptychus dybowskii, scaly osman Diptychus maculatus, Balkhash marinka Schizothorax argentatus and alien rainbow trout Oncorchynchus mykiss. Native Balkhash perch Perca schrenkii and spotted thicklip loachTriplophysa strauchii can also be caught by recreational fishermen. As a result of the negative anthropogenic impact, the Balkhash perch disappeared from most of the studied rivers, and the range of the Balkhash marinka was significantly reduced.For the sustainable existence of populations of fish caught by amateur fishermen, it is necessary to have sections of rivers protected from human impact. To organize effective management of fish resources in small rivers, further study of the regularities of their functioning is necessary.