The northern part of the Agrakhan Bay plays a major role in restoration of commercial fish stocks in the Tersko-Caspian region of the Republic of Dagestan. Here the natural bioresources of anadromous, semi-anadromous, non-migratory and lake-river fish species are being reproduced, and up to 600 million young fish species are being replenished annually. The article presents comparative data on the current state of natural reproduction of the main fish species, qualitative and quantitative changes in the structure of ichthyofauna that have occurred in this bay. As a result of this study, it has been determined that commercial species such as Caspian kutum, wels catfish, asp and vimba vimba have practically disappeared in the northern part of the bay, while the age and size-weight parameters of other fish species have increased. The reason for this situation is primarily the unfavourable hydrological regime during the spring-summer floods, which does not meet the necessary requirements for fish reproduction.

Under the current conditions of valuable fish species depletion, sturgeon aquaculture is intended to solve two major problems, such as restoring natural stocks and saturating the consumer market with delicacy products. Artificial reproduction is the only feasible way of preserving the sturgeon gene pool in Russia’s water bodies, since natural reproduction has been reduced to zero. Commercial sturgeon farming addresses the needs of the consumer market in the context of the ban on commercial fishing. The article deals with the issues of the state and prospects of sturgeon aquaculture development.

Let us consider the problem of rational layout of load-bearing structures when designing a multi-storey building. The problem is reduced to the distribution of materials for wall sections with their specified geometry, which is described by a multi-connected orthogonal polygon. The width of the walls on the entire floor is presumed to be fixed. A mathematical model of the problem has been developed that allows taking into account restrictions on certain structural elements of walls that arise in practice. A heuristic algorithm for minimizing the total cost of construction subject to the requirements for the core stiffness is proposed.

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