AbstractThe structure of zooplankton communities in the Terek–Caspian coastal region of the Caspian Sea under the conditions of flow regulation of the Terek River and its passage through the Uch–Kosinsky channel are studied. Hydrobiological material collected in the waters of the Terek coastal region of the Caspian Sea was used. Long-term data are given for the zooplankton distribution in the studied region, which reflects the nature of the influence of the sea-level regime, the arid climate, the mass development of the Azov–Black Sea invader Acartia tonsa (Dana, 1849), and the trophic pressure of another invasive species, Mnemiopsis leidyi (A. Agassiz), after the passage Terek River runoff in a new channel. The influence of these factors mainly affected the autochthonous fauna of the waters of the Terek coast. It was shown that the previously leading native species, Calanipeda aquae dulcis and Eurytemora grimmi, faded into the background for a long period. It is only in recent years that C. a. dulcis became a subdominant form in the zooplankton of the studied water area of the Caspian Sea due to a decrease in the pressure of the ctenophore Mnemiopsis leidyi.