The thesis was to develop and apply modern biotechnological approaches to increase the efficiency of artificial reproduction technologies of aboriginal fish species of the Carpathian region. The current state of ichthyocenoses in the basins of Dniester, Prut and Siret rivers within the western region of Ukraine is considered. Populations of species, which in other parts of the country have become rare or even disappeared, are preserved here altogether. Despite significant biodiversity, the volume of fish stocks, even in the most productive reservoirs of the region is extremely low. The analysis of the possible causes of the current situation did not reveal any critical problems with the pollution of the water environment or in the parasitological situation. It is shown that the potential fish productivity, calculated by the development level of the natural forage base, is more than three times the actual. Obviously, the low level of fish stocks is caused by violation of natural reproduction processes in populations of most fish species. One of the most effective ways of solving the current situation is the implementation of artificial reproduction under conditions of industrial aquaculture with the subsequent reintroduction of fish youth in the natural hydroecosystems. For the purpose of formation of broodstock herds of the aforesaid fish species, the sterlet, Rutilus frisii and common barbel were removed from the natural conditions on the basis of the permissions of the Ministry of Ecology and Natural Resourses of Ukraine. The maintenance of individuals, removed from the nature, in the RAS allowed to develop and improve the basic links of the technological process of cultivating aboriginal fish, from the procedure of domestication to the reintroduction of the received fish stock and the formation of a broodstock herd from individuals already grown in the captivity. To reduce losses during the transfer of larvae to exogenous nutrition and to obtain a stocking of aboriginal species with increased vitality, biotechnologies have been proposed for creating functional starting live feeds with a high content of polyunsaturated fatty acids and carotenoids. The expediency of carotene-producing yeast usage of the genus Rhodotorula to saturate live feeds with carotenoids was proved and the mode of this procedure was developed. The use of co-cultivation methods of Rhodotorula yeast with lactic acid bacteria allows efficient disposal of carbon-containing substrates, in particular, of milk whey. Lactic acid bacteria application has led to an improvement in the dynamics of cultures growth and increased carotenogenesis, in particular due to beta-carotene, torularhodine and torolulene synthesis. The introduction of lactobacilli positively influenced the growth processes in fish larvae in the final result. At the same time there is a suppression of pathogenic and conditionally pathogenic microflora in the fish organism and in the water where they were grown. To prevent nutrient deprivation in live feeds, the use of preparations based on yeast and algal biomass has been substantiated. The proposed effective bioencapsulation schemes provide an increase in the content of target products in feed organisms, without causing an increase in their mortality rate. Also, the proposed schemes of bioencapsulation do not lead to inhibition of either proteolytic activity or lipase and amylolytic activity in live feeds. This has a positive effect on the level of hydrolytic enzymatic activity in the digestive tract of fish larvae. It was shown that bioencapsulated starting live feeds positively affect the survival and growth processes of fish larvae. The possibility of using γ-crotonolactone drag DON-1R under conditions of RAS is shown for the first time. It has been demonstrated that the addition of the drug to feed stimulates an increase in the rate of mass accumulation in sturgeon. Cultivating fish in RAS with poor performance of the biofilter is accompanied by accumulation of nitrite ions, causing an enhanced formation of methemoglobin, which can reach 50%. It has been proven that the effective release of water from soluble forms of nitrogen ensures the use of basalt tuff from the “Politske 2” deposit, which allows it to be used for fine water purification in the RAS, as well as in the cultivation of food organisms. The proposed biotechnological approaches to the conservation and reproduction of fish resources provided the opportunity to form reproductive herds of indigenous fish species under conditions of industrial aquaculture, to get fish stocking material for Dniester and Dniester reservoir.
