The northern area of the Caspian sea, as the most valuable and unique fishery water body, is characterized by high biological productivity. The biocenoses of the Caspian sea northern area, located “at the juncture” of natural zones and adapted to significant long-term changes-return conditions of the marine environment, are “ecotone”.
The key importance of this region for the maintenance of the population specificity of biological diversity and associated with it the bioresource values of the whole Caspian sea is widely recognized.
