Characteristics of the current state of the ichthiofauna of the lake Kotlovan as a small artificial water body, Dnipro city

Purpose. To investigate the current state of nearshore and pelagic communities of ichthyofauna of an artificial water body: Lake Kotlovan in the city of Dnipro. To develop a set of recommendations and bioreclamation measures to improve and maintain a balanced ecological state of the water body, to increase its recreational value. Methodology.The study of ichthyofauna was carried out in the lake Kotlovan (total area 13.4 hectares), which was artificially created in the late 1960s and 1970s, located in the Industrial District of Dnipro in the area of industrial development. The study was carried out in September 2021 - October 2022 in three main nearshore biotopes of the water body. Ichthyological samples were collected in the nearshore shallow water zone with a small-mesh (fry) seine of 15 meters long with a mesh size of 7 mm in the wings and 3 mm in the codend. Fish selected for further analysis were preserved in a 4.5% formalin solution. Processing and analysis of the collected samples were carried out at the research center “Aquatic Bioresources and Aquaculture” of the Dnipro State Agrarian and Economic University (DSAEU). Generally accepted methods of mathematical analysis were used to process the results. The study was carried out in accordance with the Program for conducting scientific fisheries research of the Scientific Research Center “Aquatic Bioresources and Aquaculture” of the DSAEU for 2022–2026. Findings. The peculiarities of the species composition and distribution of the spontaneously formed ichthyofauna of an artificial water body under the impact of negative factors - discharges of enterprises, communal and household effluents and active recreation - have been established. Ichthyofauna of the lake Kotlovan is impoverished and represented by only 10 species (4 families). The composition of the ichthyofauna lacks bottom-dwelling fish and some littoral species (representatives of the familiesCobitidae, Siluridae, Syngnathidae, Gasterosteidae, Gobiidae), a certain deformation of the taxonomic structure was observed. The absence of individual families of ichthyofauna is an atypical situation for most water bodies in this region. This is due to the artificial development of ichthyofauna and the complex negative effect of the anthropogenic factor and internal trophic relationships. Recommendations on bioreclamation measures for the development of a stable ichthyocenosis with the improvement of the trophic structure and ecological condition of the