The results of studies on the current environmental condition of dolgin herring Alosabraschnikowiibraschnikowii(distribution, dynamics, migration, food, stocks, etc.) conducted in 2002 -2011 in the Caspian Sea are presented. The complex influence of abiotic, biotic and anthropogenic factors, negatively affecting the eco-physiological state of the population is considered. It was established that the density of the dolgin herring in different parts of the Caspian Sea is not same and there isseasonal dynamic. This is due to seasonal migrations of dolgin herring and their prey, spawning, and it is also determined with the environmental conditions of individual habitats. Dolgin herring is a fast growing fish which length and mass are various in the western part of the Middle and South Caspian (appropriately 10.6-40.0 cm, 15-1226 g).The basis of the population is made by 3-4 year individuals. Food spectrum mainly covers sprats, gobies and shrimp. At present, current environmental conditions of the Caspian Sea have positive effect on the increase in stocks of dolgin herring, in connection with which transgressiv area of distribution of this species has increased significantly.
