Ribogospodarsʹka Nauka Ukraïni (Mar 2014)
EFFICIENCY OF CONCOMITANT APPLICATION OF ORGANIC FERTILIZERS AND CULTURED INVERTEBRATES FOR INCREASING FISH PRODUCTIVITY IN NURSERY PONDS
Abstract
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.
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