EFFICIENCY OF CONCOMITANT APPLICATION OF ORGANIC FERTILIZERS AND CULTURED INVERTEBRATES FOR INCREASING FISH PRODUCTIVITY IN NURSERY PONDS

Purpose. To study the fisheries and biological indicators of young-of-the-year carp when applying fertilizer in ponds, introducing stock cultures of Daphnia magna (Straus) and feeding of young-of-the-year with cultured zooplankton organisms and to evaluate the effectiveness of measures for enhancing the provision of young-of-the-year carp with natural feeds. Methodology. Stock culture of Daphnia magna was added into experimental ponds, 65 kg/ha of zooplankton, which were cultured in a pond-cultivator and cages installed in experimental ponds were used for feeding young-of-the-years in July and August. For study of nutrition and growth of young-of-the-year carp, samples were taken during regular control fish seining. Parameters of young-of-the-year carp growing and economic efficiency of measures aimed at increasing the supply of young-of-the-year carp with natural feeds were determined. Findings. Average seasonal zooplankton biomass in experimental ponds was 3,9 – 4,8 times higher than the biomass in the control pond. Natural food in the stomach content of carps from experimental ponds in June was 64,7 – 71,3 %, in July it decreased to 48.0 %, in August ― to 15,0 – 2,0 %. Natural food part in young-of-the-year diet in June was 9,3 %, in July ― 20,6 – 2,1%, in August ― 1,1 – 0,4 %. Fish productivity in experimental ponds was higher by 35,2 – 4,5% than that in the control pond. Expenditure of grain feeds for the growth of young-of-the-year carp in the control pond was 3,2 units, in the experiment it was 12,5 – 15,6 % lower. Profit from growing young-of-the-year carp in experimental ponds was 2,9 – 3,7 times higher than in the control and was 3955,2 – 5153,0 UAH/ha. Profitability of growing young-of-the-year with the use of intensification measures was 2,6 – 3,2 times higher than that in the control pond. Originality. For the first time we studied fisheries and biological indicators when growing young-of-the-year carp with the use of a complex of measures for enhancing the provision of their natural feeds, which included organic fertilizers, application of a stock culture of Daphnia magna and feeding of young-of-the-years with cultured zooplankton organisms. Practical Value. It was found high economic efficiency of measures aimed at improving provision of young-of-the-year carp with natural feeds, which serves as the basis of their wide implementation into production