The effect of the nematode Contracaecum (Ascaris) on fish of the cooling reservoir of the Zaporizhzhzia nuclear power plant

Purpose: To determine species composition and localization of anisakidosis pathogens, infestation fish in the Zaporizhzhia NPP cooling reservoir, identify trends their compared to monitoring epizootic studies last year. Methodology. In course work, we used generalized results conducted summer autumn 2021. The ZNPP reservoir as well parasites Anisakidae family were determined. carried out using method incomplete parasitological dissection at laboratory. Nematode larvae detected by visual inspection. identified identification keys. washed with a saline stored 70% ethanol. For quantitative analysis parasitofauna, such parameters prevalence (%) intensity (ind./ fish). Findings. showed that Contracaecum (Ascaris) found European, channel redtail catfishes, which localized cysts or free-living abdominal cavity. intensify reached 86 ind./fish, 100%. caused hyperemia (redness) inflammation internal organs. At same time, no common silver carps. Compared 2020, was less pronounced, namely: monogenean Dactylogirus on gills carps ciliates including Trichodina Apiosoma, small amounts body surface invasion catfish decreased 17 %. Originality. first large tendency spread among detected, namely catfishes. importance threat this for established. Practical value. obtained can be timely develop sanitary preventive measures reservoir. Key words: nematodes, (Ascaris), fish, ZNPP, anisakidosis, prevalence, intensity, anisakids (Anisakidae).