INCREASING FISH PRODUCTIVITY OF POND ECOSYSTEMS BY FERTILIZING THEM WITH DISTILLER'S GRAINS

Purpose. To study fish culture parameters of young-of-the-year carp in the conditions of industrial fish-growing ponds when applying experimental repeated fertilization with distiller’s grain. Methodology. The study was conducted in industrial fish-growing ponds. The wastes of alcohol industry ? the distiller’s grain as organic fertilizer was gradually introduced into ponds at following amounts: first application ? 1,0 t/ha, second application in 10 days ? 0,5 t/ha, third application in 12 days ? 0,5 t/ha. The control ponds were fertilized with humus (2 t/ha). Young-of-the-year carp were grown in monoculture at stocking density of 30 000 fish/ha. In addition, 100 kg/ha of lime were applied during the culture season in the experiment and control. Fertilization with humus and application of lime in ponds, hydrochemical studies, sampling and processing of hydrobiological samples, fish culturing and statistical studies were carried out according to standard methods. Findings. Gradual fertilizing with distiller’s grain (to the total 2 t/ha) gave the possibility to create favorable hydrochemical and hydrobiological regimes. An average daily growth in the experimental fish groups of 0,44 ± 0,09 g/day that was similar to in the control (0,45 ± 0,11 g/day) with positive significant correlation between them (r = 0,97; p <0,001) was achieved. The performed measures gave a possibility to obtain fish productivity in the experimental variant 10.7% more than in the control. An economic effect of 14.3% cost reduction for fertilizing ponds was achieved. Originality. For the first time we presented the results of fish culture and biological parameters of young-of-the-year carp in industrial ponds when applying 3-time fertilization with distiller’s grain. Practical Value. The obtained results are the basis for the broad use of non-traditional organic fertilizer ? distiller’s grain in industrial ponds, when growing young-of-the-year carp in monoculture.