Polishchuk O. Technological bases of reproduction and cultivation of pike perch (Sander lucioperca) using combined methods of fish farming in the farms of Polissya and Forest-Steppe of Ukraine.

The thesis is devoted to the improvement of technological elements for artificial reproduction and rearing of young pikeperch to the stage of young-of-the-year. It was established that the use of the drug "Vadilen" is 7.8% of the drug itself. As a result of the efficiency accident, Surfagon appeared with an efficiency of 7.4%. The best indicators were presented in variants with different hypophysis, which showed the highest effectiveness ‒ 6.9%. However, when using the drug "Vadilen", a low indicator of the release of the prepuce from frozen cases was noted ‒ 27.8%, and the release of larvae from the prepuce ‒ 30.5%. It was determined that the optimal stocking density of pikeperch larvae in the basin cultivation technology is 40,000 specimens/m3 at the 1st stage, and 10,000 specimens/m3 at the 2nd stage. At the III stage of growing, the recommended planting density is 10,000 specimens/m3. With such a cultivation scheme, it is possible to get from 21 to 35.8 kg/m3. It has been proven that the application of combined technology using artificial spawning and cultivation in farms allows to obtain this summer at an average level of 80.2‒83.0% in one growing season. survival rates, weighing from 55.6 to 68.7 g, fattening ratio 1.78-1.94 units. With the application of combined technology using natural spawning and rearing in pools, we get this yearling with an average weight of 76.5–88.4 g with an average survival rate of 74.0-82.0%. It was determined that the economic effect for growing this summer in pools is 21.3–30.5%, for combined technology ‒ 24.7-26.4%. The analysis of productive and reproductive indicators of broodstocks of natural and domesticated broodstocks proves that broodstocks of the domesticated form had an advantage in terms of morphometric indicators. According to the overall average indicator, domesticated females prevailed over females of the natural population by 5.7% in terms of produced eggs, 13.5% of working fertility, respectively, in domesticated females, the number of eggs in 1 g was on average 1166.0 eggs, in the natural population ‒ 1181.7 eggs. The average indicator of the volume of ejaculate in domesticated breeders was 2.0 dm3, and was higher than the indicator of males from natural reservoirs by 7.5%. However, juveniles obtained from breeders of natural populations were characterized by higher larval survival rates, but low resistance to stressful situations was recorded.