Abstract
In the middle of the last century, in order to make rational use of the biological productivity of Inland water bodies in the USSR, full-scale ichthyintroduction works were carried out. In this regard, a complex reconstruction of the ichthyofauna was carried out of the Ile-Balkhash basin. The results of these studies led to a change in the species composition of the hydroparasitocenosis, the appearance of foci of ichthyozoonosis invasions and the worsening of the epizootological situation in the basin. The article provides information about the current state of the hearth of ergasilesis arising out of ichthyintroduction.