AVAILABILITY OF WATER RESOURCES FOR THE FISHERIES OF THE LOWER DON RIVER
S. V. Zhukova
Abstract
The Lower Don fishing area is of crucial importance for the reproduction of fish stocks in the Azov Sea, as the spawning grounds of valuable anadromous and semi-anadromous fish species are located in the \nsection of the Don River from the Tsimlyansk Reservoir to its estuary. One of the main reasons for the catastrophic decline in the fish productivity of the Azov Sea is irregularity of spring flooding of the floodplains, on which the spawning grounds of sturgeon fish species, bream, zander, roach, vimba bream, shemaya, herring and other fish species of commercial importance are historically located. The water supply of the Lower Don under the conditions of anthropogenic and climatic transformations of the Don River flow was analyzed; causes of disruption of the natural reproduction processes for anadromous and semi-anadromous fish species were identified. Analysis of the structure of natural and regulated runoff of the Don River, for which the data, collected during long-term observations at the hydrological station in the Don River (Razdorskaya Settlement) were used for the period from 1912 to 2018. Grapho-analytical and mathematical statistical methods of analysis for the hydrological data series were applied. The reasons for disruption of the processes of natural reproduction are indicated, and the periods when the regime of floodplain flooding facilitated the effective spawning of fish are identified; the years, when it was not possible to accomplish ecological and fishery augmentations (water releases from the Tsimlyansk Reservoir), have been established as well. A set of measures to restore impaired fisheries capacity of the Lower Don Basin and the Azov Sea is proposed.