Comparative results of experimental work on the study of stellate sturgeon offspring obtained using cryopreserved (experimental) and native (control) sperm, carried out at the scientific and experimental complex of aquaculture “BIOS” of the Volga-Caspian branch of VNIRO (CaspNIRKH) in this article were presented. Molecular genetic studies of cryopreserved sperm, females and males from the brood stock of the complex were carried out. In order to select the optimal parental pairs, calculations of genetic relationship of fish spawners were made. The scheme of the experiment was developed. The technological process of working with stellate sturgeon spawners was described: obtaining mature reproductive cells, insemination, incubation of caviar. Holding and breeding of the studied groups of stellate sturgeon juveniles up to standard weight was carried out. Each stage of the research work was subjected to comparative analysis. The genetic diversity of juveniles was studied. As a result of the work carried out, it was found that the group of fish obtained using of cryopreserved sperm had higher weight indicators, compared with the juveniles of the control group obtained from males from the brood stock of “BIOS”, by an average of 16%. In addition, the experimental group had a higher homogeneity compared to the control group, as evidenced by the values of the coefficients of variation. The survival rate of juveniles of the experimental group of fish was higher than the control group by an average of 10%. The stellate sturgeon obtained using cryopreserved sperm was characterized by higher values of the total number of alleles and the absence of a deficit of heterozygotes compared to the control group of juveniles, which is especially important for preserving the diversity of this valuable sturgeon species. The results of the research work carried out will help develop proposals for the formation of artificially created sturgeon brood stocks by replenishing them with juveniles obtained using cryopreserved sperm and having higher fish breeding biological and genetic indicators. This will allow the herd to have a stock of working material from different generations of sturgeon species, which is a promising factor for the conservation of aquatic biological resources and selection in commercial aquaculture.

The objects of research are Beluga (Huso huso, Linnaeus), sturgeon spike (Acipenser nudiventris, Lovetsky) and their interspecific hybrids of artificial generation grown on the Research and Experimental Base BIOS (the Astrakhan region) by using the basin method. To assess the physiological status of fish, a set of morphophysiological indicators (absolute and relative weight of gills, heart, liver, and gonads) were used. The dynamics of the indices of the corresponding viscera of Beluga and sturgeon spike and their interspecific hybrids in the second year of cultivation was studied. The necessity for the research is explained by the fact that most work performed was carried out on land vertebrates and on fish of natural generation. There have been presented the average values of morphophysiological indices for each of the four groups of unmixed sturgeon species and their hybrids. The obtained values of the studied parameters of sturgeon species can be used for further monitoring of the fish growing conditions using the basin method.

The article describes the problems, which are of greatest interest for the formation of fish broodstock, such as the process of gameto- and gonadogenesis and duration of spawning cycles in broodstock reared in artificial conditions. Under the Research and Experimental Aquaculture Complex BIOS of CaspNIRKH in the formed paddlefish broodstock 63 females matured in 2020. There were studied 11 paddlefish females born in 2002 and 2003, whose roe was taken for food purposes. The following parameters were determined: age of sexual maturity, duration of the spawning interval, body weight, ratio of eggs to the fish body weight. The physiological state of paddlefish females upon obtaining roe was assessed by biochemical parameters of blood: hemoglobin concentration (Hb) and total serum protein (TSP). The parameters of the reproductive function of paddlefish females obtained in the research were lower than the parameters characteristic for paddlefish in their natural habitat, and lower than the parameters of the first acclimatizers in the Krasnodar region. Sexual maturity of the studied females came quite late - at the age of 14-15, which is 1-2 years more than in the conditions of the Krasnodar region. The spawning intervals of the studied paddlefish females turned out to be 1-2 years longer than in the natural conditions. The ratio of eggs to the female body weight was about 10%, which is 1.5 times less than that observed in the American paddlefish in the natural conditions. At the same time, the biochemical parameters of blood (hemoglobin concentration and total serum protein, which characterize the physiological state of paddlefish females) turned out to be rather high and indicated a satisfactory condition of the fish. The preliminary results obtained make it possible to recommend the fish farmers of the enterprise to improve the work with paddlefish broodstock, paying special attention to optimizing the conditions for fish rearing at the stages of gonad formation.

The article presents the comparative results of the experimental work on studying valuable pure species offspring (white sturgeon, fringebarbel sturgeon) and their interspecies hybrid forms (white sturgeon × fringebarbel sturgeon and fringebarbel sturgeon × white sturgeon) in the early stages of ontogenesis. The tests were carried out in the research and experimental base BIOS (the Astrakhan region) in 2019. The fish-breeding and biological characteristics of the producers of parental species that participated in the crossing to produce reciprocal hybrid forms are presented. The interbreeding scheme was developed. The complex study was conducted at the stage of the early ontogenesis. Observing over eggs development took place at all significant stages of embryogenesis. The survival rates of one-day prolarvae of all experimental groups, in relation to the eggs laid for the incubation, and their weight data became the result of the experiment. The results of the experimental work will help to develop proposals for the exploitation of broodstock producers of pure sturgeon species to produce hybrid offspring, which may have increased growth and survival rates both at the stages of embryogenesis and the active feeding of larvae, and during juveniles rearing, which is a promising factor for commercial aquaculture.