Analysis of reproduction conditions for native ichthiopopulations in the Styr-Horyn hydroecological corridor on the territory of the Western Polissiya of Ukraine

Purpose. To investigate the state of reproduction conditions, current and in dynamics since 1922, for native ichthyopopulations (NI) of the Styr-Horyn Hydroecological Corridor (HEC) on the territory of the Western Polissiya of Ukraine. Methodology. The Styr-Horyn HEC was studied according to the following parameters: hydrological regime and duration of water stay on the floodplain; state of the basin surface; speed of channel flow; amount of water exchange; quality of aquatic environment; natural-temporal changes of the channel, floodplains, tributary network; number of ecotones; qualitative and quantitative characteristics of fish juveniles. The hydrological regime was studied using the analysis of runoff hydrographs located in the Volyn, Rivne, and Zhytomyr regions starting from 1922. To assess water quality, KND No. 211.1.4.010-94, “Methodology of ecological assessment of surface water quality by relevant categories”, SOU – 05.01.37-385: 2006, was used. Ichthyological studies were carried out in the field and laboratory according to standard methods with the use of identification keys primarily using the data of test catches and the classification of V. G. Nikolskyi. Statistical and mathematical analysis was performed using the Delfi programming language, relevant computer programs (Mathcad, Excel, Xara) and formulas, including authors' ones. Findings. An analysis of the Styr-Horyn HEC was carried out on the basis of restorative ichthyoecology using the basin principle and riskology approaches. The hydroecological and ichthyoecological factors affecting the reproduction of NI were studied. The natural fish reproduction localities (NFRL) in this region have been identified. Originality. For the first time, a comprehensive analysis of the state of the reproduction conditions of the Styr-Horyn HEC on the territory of the Western Polissiya of Ukraine was carried out starting from 1922. In addition, a prognostic assessment of the NFRL of this HEC on the territory of Ukraine has been provided. Practical value. The conducted studies are already successfully used in the work of higher educational institutions of Ukraine in the field of training “Aquatic bioresources and aquaculture”.In addition, they are used by fish protection authorities in several regions of Ukraine, in particular for certification of wintering grounds. In the future, their implementation is planned at the level of the national environmental protection policy and in the preparation of regulatory documents regarding the determination of the damage caused and the extent of the damage.