58their impact on the biota. The radionuclides released into aquatic ecosystems migrate and are most effectively accumulated by the upper trophic levels to which the fish belongs, serving as an important object of radioecological monitoring. The relevance of this study is to detect the influence of radionuclide contamination on the appearance of morphological skeletal anomalies in the fish species typical for the reservoirs of the Chornobyl Exclusion Zone, which is a representative exemplar of fresh aquatic ecosystems, taking into account the peculiarities of its way of existence. The novelty of the work is determined by the fact that for the mentioned reservoirs the relevant study was conducted for the first time.