Fish species richness and species diversity in the Uday river within the national nature park «Pyryatynsky»

Objective. Determination of species richness, species diversity and distribution of fishes in the Uday River within the National Nature Park “Pyryatynskiy” as well as determination of the prioritization in providing the special protection regime for some water areas. Methodology. The object of study were small-sized fish populations of the Uday River. Sampling was carried out with the framework of monitoring works in association with scientific department of National Nature Park in July 2014-2017. The study was performed in Pyriatynsky district, Poltava region, along the Uday River channel on the territory of the National Nature Park. Monitoring catches were conducted at depths up to 2 m by a beach seine of 6 m in length, mesh size of 5 mm. Sample processing was carried out in accordance with generally accepted methods. Findings. 19 species of fish belonging to 6 families were found on National Nature Park "Pyryatynsky" territory in the catches of 2014-2017. The largest species richness was found on a station near the village Kaybalovka (14 species). Almost the same number of fish species were observed at all stations. According to the calculated species diversity indices, the highest species diversity index was determined for the station Kaybalivka. Also we calculated the Jaccard similarity coefficient. The most unique water area, according to the calculations, was the area near the station Kaybalivka. A special protection regime should be assigned to this particular water area. Originality. Any information on fish species diversity in some water areas of the Uday River is absent in the literature, but by using information about changes in species diversity it is possible to draw conclusions about the proper state of the protection of aquatic ecosystems at a specific time. Therefore, the species diversity and distribution of the Uday River has been calculated, and the priority has been given to provide a special regime for the protection of the water area near the village Kaybalivka. Practical value. The obtained data have been used in the development of plans for the conservation of the biological diversity of the national park, and in the preparation of the management plan of the Emerald Network Europe Project UA0000077.