Systematically related species are species that came into the environment specifically or accidentally, in addition to their main habitat. These species adapt quickly, when the environment for them is  favorable. Alien species are widely distributed throughout the world and are found in all categories of living organisms (plants, animals, fish, etc.) and in all types of ecosystems.

According to the latest data, black bream, whitefish, tilapia, snakehead live in the Ili River and the Kapchagai reservoir. Almost all of this fish came from neighboring China, that is, from the transboundary Ili River. Exotic species have a negative impact on biodiversity, ecosystems, and populations. They lead to habitat changes, competition for nutrients, predation, disease and loss of genetic diversity.

Scientific research is needed to determine the presence of alien species in water reservoirs. Preservation of biodiversity is an urgent problem today. This is reflected in the Convention on Biological Diversity. In order to resolve this issue, the “RPC of Fisheries” LLP has begun to conduct research within the Program “Comprehensive assessment of the status of fish resources and other hydrobionts of the main fishery reservoirs of Kazakhstan and development of evidence-based recommendations for their sustainable use.”