BIODIVERSITY OF OBJECTS OF AQUATIC BIORESOURCES OF THE VOLGA-CASPIAN FISHERY AREA
In the course of the study there has been carried out the analysis of the data (both first-hand research and literature data), which characterize different species of fish, Caspian seal, river and crayfish and lobsters of the Volga-Caspian fishery basin. There have been listed families and species composition of the water biological resources on the water area of the Volga-Caspian fishery basin - 125 species and subspecies of fish (only 35 species are used in commercial fishing), belonging to 21 families. They have been divided into ecological groups according to spawning zones, preferred habitats and types of nutrition. Main features of ecological changes happened in the Caspian Sea for the last 65-70 years and resulted in drastic drop of fish catch volumes including sturgeons have been considered. In the populations of all sturgeon species there is a marked trend to dominating the young fishes - up to 80%. Increase in the number and improved biological characteristics was registered only in anadromous herring ( Alosa kessleri kessleri ) sires. Caspian seal retains the number of population on the level of the average annual figures, which is related to the favorable conditions for fattening and absence of critical epizootic situations. Materials on the long-term changes in the level of the Caspian Sea have been analyzed. The correspondence of sea level fluctuations and the size of commercial catches has been studied. The recommended measures for maintaining and development of the fishery complex in the Russian area of the Caspian basin (the Russian region) have been listed. The preservation of natural populations of all fish species, especially sea fish, anadromous fish of the Caspian Sea seems to be possible only if there are coordinated actions of all littoral states for preventing sea water pollution in the process of exploration and extraction of raw hydrocarbons, providing international inspections over preventive measures and creating the preserve zone in the North of the Caspian Sea (Russia, Kazakhstan).