Ecological and fisheries aspects of the formation of the modern hydrological regime of the water bodies of the Azov–Don Region. Part 1: Anthropogenic and climatic changes in the flow of the Don River; fisheries requirements for the water bodies of the Lower Don
Authors:   Russian Federal Research Institute of Fisheries and Oceanography (FSBSI “VNIRO”), Azov-Black Sea Branch of the FSBSI “VNIRO” (“AzNIIRKH”), Zhukova S. V. , Podmareva T. I. ,   Russian Federal Research Institute of Fisheries and Oceanography (FSBSI “VNIRO”), Azov-Black Sea Branch of the FSBSI “VNIRO” (“AzNIIRKH”), Taradina E. A. ,   Russian Federal Research Institute of Fisheries and Oceanography (FSBSI “VNIRO”), Azov-Black Sea Branch of the FSBSI “VNIRO” (“AzNIIRKH”), Lutynskaya L. A. ,   Russian Federal Research Institute of Fisheries and Oceanography (FSBSI “VNIRO”), Azov-Black Sea Branch of the FSBSI “VNIRO” (“AzNIIRKH”), Burlachko D. S. ,   Russian Federal Research Institute of Fisheries and Oceanography (FSBSI “VNIRO”), Azov-Black Sea Branch of the FSBSI “VNIRO” (“AzNIIRKH”), Karmanov V. G. ,   Russian Federal Research Institute of Fisheries and Oceanography (FSBSI “VNIRO”), Azov-Black Sea Branch of the FSBSI “VNIRO” (“AzNIIRKH”), Bugaev L. A. ,   Russian Federal Research Institute of Fisheries and Oceanography (FSBSI “VNIRO”), Azov-Black Sea Branch of the FSBSI “VNIRO” (“AzNIIRKH”), Belousov V. N. ,   Russian Federal Research Institute of Fisheries and Oceanography (FSBSI “VNIRO”), Azov-Black Sea Branch of the FSBSI “VNIRO” (“AzNIIRKH”)
Published: December 2024

Background. This study, consisting of two parts, examines the ecological and fisheries aspects of climatic and anthropogenic transformations of the hydrological regime in the Don River Basin, the requirements of the fisheries industry to the Lower Don water supply, both prescribed and actually met (Part 1), as well as the issues of fulfilling the fisheries needs by the floodplain spawning grounds of the Lower Don in their current geobotanical state, changes in the habitat conditions of the aquatic bioresources in Taganrog Bay utilizing it as a receiving reservoir for the adaptation of juvenile fish to marine conditions, and the efficiency of the Ust-Manych fish passage channels during the spawning season (Part 2). The functioning of the aquatic and near-water ecosystems of the Azov–Don Region along with the processes of natural reproduction of fish depend on the hydrological regime of the Don River, the degree of impact of anthropogenic and climatic factors, and the methods of water resource management in the Don Water Management Complex (DWMC). Relevance. The ecological and fisheries aspects of the formation of the modern hydrological regime in the Lower Don Basin, as well the regulatory practices for the water regime of the Tsimlyansk Reservoir and their legal implications are considered; the main reasons for the limited possibility of organizing water releases with ecological and fisheries purposes are stated. The aim of this work is to assess the possibilities of meeting the demands of fisheries with the water resources of the Tsimlyansk Reservoir in the context of changes in the modern hydrological regime of the Don River. Methods. The data on the flow of the Don River collected at stanitsa Razdorskaya and published in the annual reference publications of Roshydromet (to 1991) have been used, as well as the data on the average monthly and maximum water consumption (stanitsa Razdorskaya) for the period 1992–2023 that were obtained from the North Caucasus Office for Hydrometeorology and Environmental Monitoring (SK UGMS) on a contractual basis. The daily monitoring data for the hydrological regime of the Tsimlyansk Reservoir have been acquired through the website of the Don Basin Water Administration (DBVU). Archival and published data on the investigated subject matters have also been used. Methods of mathematical statistics and graph- analytical construction have been applied during the data processing. Results. In the Don River Basin, the trend for a decrease in the volumes of annual and spring runoff under the influence of climatic and anthropogenic factors is observed, which obstructs the flooding of the floodplain spawning grounds and hinders the natural reproduction processes. Conclusion. In the process of integrated use and intersectoral distribution of water resources of the Tsimlyansk Reservoir, the economic feasibility is prioritized over environmental sustainability. The spring ecological and fisheries-related water releases have not been possible in the Lower Don Basin in recent years (1994–2024).