The priority areas of the research were the upper zones of the reservoirs (the hydrological regime of which is close to the river one), as the most suitable areas of the water area for the habitation and reproduction of sterlet.
Samples for hydrochemical analysis were collected from the surface (at all stations) and bottom (at channel stations) horizons. Bottom sediment samples were collected along the channel.
Hydrobiological studies included sampling of phyto-, zooplankton and macrozoobenthos in accordance with the methodological recommendations. The state of key communities of aquatic organisms (phyto-, zooplankton and macrozoobenthos) was assessed by the number of species, total abundance, total biomass, proportion of the total abundance and biomass of communities of the main taxonomic groups, and composition of dominant species.
Material was collected to assess the abundance and biomass of commercial fish species during the spawning period, and habitats of sterlet in the waters of the Volgograd and Saratov reservoirs were determined. Adult specimens were counted using net fishing with different-mesh (28-140 mm mesh) fixed nets. The migration of larvae and early juveniles of sterlet was counted using passive net fishing gear - ichthyoplankton cone nets (ICN) below the expected spawning grounds and in the central part of the water flow passing through the spawning grounds.
The samples and materials collected during the expedition were transferred to the laboratories of the Saratov branch of VNIRO for subsequent office processing. The results obtained will allow us to draw scientifically based conclusions about the state of aquatic biological resources in the Volgograd and Saratov reservoirs and their habitat, predict their further development and ways of conservation.
Press service of VNIRO