Natural food base of fish culture ponds and its use in growing fellow of carp

Abstract

   A study of the natural food supply of the nursery ponds of Ecopark LLC’s fish farm in the Moshkovsky district of the Novosibirsk region was carried out in July–August 2022. Carp fingerlings were raised in the ponds with a stocking density of 34.77 and 57.73 thousand/ha. During the growing period, carp fingerlings were fed 5000 kg of feed mixture in equal parts of crushed barley and wheat grains. The species composition of zooplankton in the studied reservoirs is monotonous and is represented by nine species. Variable species diversity was observed in all reservoirs. The number of zooplankton in July in ponds No. 5 and No. 2 was 76344.45 and 48311.11 ind./m3, in August – 56800 and 48616.67 ind./m3; biomass – in the range of 2724.88-5777.86 and 1618.65-2258.73 mg/m3, respectively. Analysis of variance showed a relationship between the mass of under-yearlings and zooplankton biomass. It is 0.70, which indicates that the mass of carp under-yearlings increases with an increase in zooplankton biomass. The identified differences in the rates of linear growth and weight depending on the stocking density make it possible to establish fish productivity - in pond No. 2. It was 806.4. In pond No. 5 - it was 878.4 kg/ha. Planting 37.33 ind./ha is more productive and gives better growth indicators (average length and weight of carp fingerlings at the end of the study are 10.91 cm and 26.96 g, respectively) than planting 57.77 ind./ha (average length and weight at the back of the study 9.70 cm and 18.67 g, respectively). The planting density of 37 thousand specimens/ha makes it possible to grow fingerlings with a standard weight of 25-26 g. The influence of the stocking density factor on the weight of fingerlings is 0.92 (at a level of P > 0.001). Fish productivity in Pond No. 2 was 806.4 kg/ha, and in Pond No. 5, it was 878.4 kg/ha.