Ichthyofauna of the Alakol System of Lakes and Ways of Its Formation. A Review

The review describes all findings of alien fish species in the water bodies of the Alakol system of lakes. Since 1932, 25 fish species have been introduced here, nine of which were introduced intentionally, while the rest were released accidentally. In the 20th century, species were introduced to increase fish productivity of the lakes. Currently, fish are introduced accidentally, owing to the transboundary transfer of new species along the Emel River from the People’s Republic of China. The naturalization of invasive species has led to the displacement of native species from the terminal water bodies in the lowlands to the foothill zone and overgrown biotopes of water bodies. The endemic species, Balkhash perch, remains abundant in a deeper part of Lake Alakol and in the overgrown biotopes of adjacent water bodies. The fact that predators capable of hunting in overgrown biotopes (pike, Amur catfish, and snakehead) have appeared in Lake Alakol in recent years poses a threat to Balkhash perch populations in overgrown biotopes. If a predator capable of colonizing the deep-water zone of Lake Alakol with its salinity of up to 11‰ is introduced, the fish species is assumed to pose a threat to continued existence of the highly abundant population of Balkhash perch. The article has proposed measures to reduce the risks to the existence of numerous populations of Balkhash perch in the water bodies of the Alakol system of lakes.