Conditions for carp growing in feeding ponds of the Yaniv fishery

Abstract

The article presents the results of research on the ecological conditions of carp farming in feeding ponds, which were carried out on the basis of the fishery “Yaniv”, which is part of PrJSC “Lviv Regional Fish Production Plant”. The research was carried out during the vegetation period of 2019 in accordance with the methods adopted in hydrobiology and fish farming. The hydrochemical state of the studied reservoirs and their biotic component, in particular zooplankton and zoobenthos, were analyzed. The results of studies of water quality of feeding ponds of the fishery “Yaniv” show that the hydrochemical parameters during the study period in the vast majority were within the maximum permissible concentrations set for fish farms; sometimes were registrated some indicators which slightly exceeded the normative limits, in particular permanganate oxidation, nitrites, phosphates, chlorides. The study of the natural forage base by zooplankton and zoobenthos revealed that the values of development of the studied aquatic organisms corresponded to the limits of development, which are characteristic of the ponds of the studied type of the Forest-Steppe zone. The values of zooplankton biomass in the experimental ponds were in the range of 5.3–12.5 g/m3. The dynamics of zooplankton development in feeding ponds shows its maximum development in early summer and some decrease in the second half of the vegetation season. In general, the basis of its biomass was consisted of Cladocera (Daphnia magna Straus, Bosmina longirostris, Daphnia cucullata Sars, Ceriodaphnia quadrangula OF Müller, Moina rectirostris Leydig), representatives of Copepoda (Thermocyclops crassus Fischer), Calanoida (Diaptomus castor Jurine, Eudiaptomus coeruleus Fischer) and Rotatoria (Brachionus diversicornis Daday, B.calyciflorus Pallas, Filinia longiseta Ehrb., Keratella cochlearis Gosse). Cladocera and Copepoda made the largest contribution to biomass, while Rotatoria had almost twice less share of total biomass. Indicators of zoobenthos biomass in ponds were in the range of 4.9–6.8 g/m2. The maximum development of benthic organisms was observed in late spring. The basis of biomass of zoobenthos was mainly consisted of insect larvae and oligochaeta.