Delta and delta front of the Volga river are the main fishing areas in the Astrakhan region, which provide high fish capacity. At the same time, productiveness of fishing in these areas is extremely unstable because they are effected by numerous environmental factors. The essential factor is changing the level of the Caspian Sea, which is directly related to hydraulicity of the Volga watershed. Sea-level change results in changing the area of shallow water zone and coast line, which strongly impacts on a previous biotope. Besides changing the sea level and the volume of fresh-water flowing, water bio-resources are influenced by the volume of spring flood, terms of the flood beginning and thermal regime in the region. Interference of all these factors impacts on stock forming and on fishing of all fish species caught in this region. But this interference of different fish groups (semi-anadromous, river, non-migratory) is ambiguous, which is related with their biology. The purpose of the research is to define the influence of these factors on fishing one of the most important commercial fish species - sheatfish ( Silurus glanis ). The analysis of the available materials has shown that sheatfish catches in a great degree depend on some abiotic factors. Thus, raising the sea level leads to the decrease of sheatfish catches, and increasing of water mass during the flooding period in the Volga river results in lowering the total catch. Later beginning of the flood period improves the effectiveness of fishing, as well as early warning-up of water.

The article shows the assessment of fishing conditions of roach catches (the number of fishing grounds, fishing gears, catches, catches per unit of fishing effort, fishing intensity, etc.) at the main fishery objects of the Volga delta. There has been made the analysis of structure of size and gender composition of roach from commercial and amateur catches. The results have shown a depression of the population with negative dynamics in future. There have been determined main negative factors affecting the state of roach stock: unfavorable hydrological regime, incoordination in terms of commercial and amateur catches, limits of catch and size. In such circumstances the major purpose is to create a fishing regime, when maximum pass of fish spawners to spawning grounds is provided. The article proposes organizing a special regime of fishing roach with the aim to introduce additional limitations to the commercial fish catch, the main point of which is a transition from fine-meshed seines to medium-meshed seines in the day, when the water level in the Astrakhan region achieves an index mark as 350 cm. This measure will allow assuring a maximum pass of roach spawners to spawning grounds. A similar interdiction must be valid for amateur fishing. It should be noted that this interdiction is a provisional measure allowing to preserve and reproduce roach population.

The protected area having the particular legal and regulatory status of restricting fishing in its waters has been set up to preserve and rationally use fish stocks within boundaries of the Volga estuarine area. The article presents the analysis of fishing regulations for the Volga-Caspian basin (Astrakhan region) in terms of establishing the boundaries of restricted estuarine area of the Volga. There has been given the dynamics of forming modern borders of the restricted estuarine area of the Volga, according to which, the square of its water area has decreased by 10 times over the last century. It has been noted that the establishment of river and sea boundaries of the restricted estuarine area of the Volga was based on two important principles: the first (permanent) - with reference to fixed objects (settlements, islands, etc.) or to geographical coordinates; the second (dynamic) - to the isobathic curves of depths. The second principle implies to annually revise the river and sea boundaries of the restricted estuarine area of the Volga depending on fluctuations of the Caspian Sea level. In the context of current dynamics of delta development (annual changes in depths of the lower reaches of the delta and avandelta of the Volga river) it has been recommended to use the second principle of the establishment of river and sea boundaries of the restricted estuarine area of the Volga. It has been offered to set annually the boundaries of the restricted estuarine area of the Volga according to the actual boundary of kultuk zone of the Volga delta, and its sea boundaries - according to 1.5 - meter isobathe after ice breaking.