Depression due to Genetic Instability of the Population of Diploid-Polyploid Complex of Spined Loach Cobitis elongatoides - Taenia - Tanatica of the Irpin River Caused by Pollution and Enhanced by the Hostilities' Consequences

The diploid-polyploid complex of the spined loach Cobitis elongatoides - taenia - tanaitica is a model object of evolutionary-ecological studies. The mass genetic instability of Cobitis taenia s. l. populations attracts special attention in the rivers of the right bank of Ukraine, in particular in the Irpin River. The genetic structure of the local population in the Irpin River was monitored in four sites of the middle river section over the years 2001-2024. A cycle of alterations associated with manifestation of genetic instability of clonal polyploids has been established. In 2001-2002 there were no or only single cases of the allozyme spectra abnormalities against the background of high population density and prevalence of the species throughout the riverbed. In 2004-2021, the mass of anomalies was observed, which were registered in 70-96% of individuals. At the same time, the species' numbers gradually decreased and population was fragmented into isolates. Over 2023-2024, owing to the hostilities and rapid decrease of the Irpin River flow rate, genetically altered individuals disappeared, which ultimately caused sharp decrease in the spined loach numbers. Therefore, genetic instability of the clonal spined loach is a sensitive bioindicator that is the first to clearly respond to the genotoxicity of the environment, and after the destruction of hydraulic constructions that ensured flow, responded to rapid changes in ecosystems.