Cultivation of two-year-old pikeperch (Sander Lucioperca L.) in cages with different stocking density: fish-breeding indicators and growth model

The results of the study on the effect of stocking density on the efficiency of growing one-year-old pikeperch in cages installed in a natural water body are presented. Pikeperch with an initial weight of 7.6 g were grown for 117 days in three cages at different stocking densities — 50, 60 and 70 fish/m2. The temperature regime was natural and varied in the range from 15 to 23 °C during the study period. The results of the study showed that the lowest stocking density had a positive effect on fish growth, which was most intense when pikeperch were grown at a density of 50 fish/m2 — the final body weight of fish in this group was 60.2 g. The body weight of fish grown at a stocking density of 60 and 70 fish/m2 was 48.0 and 38.6 g, respectively. As the fish density in cages increased from 50 to 70 fish/m2, the feed conversion ratio (FCR) and the coefficient of variation of final body weight of fish (CV) increased: FCR from 1.31 to 1.68, CV from 6.8 to 16.6%. The survival rate of pikeperch in all experimental variants was similar — 97–98%. The use of single-factor analysis of variance (ANOVA) made it possible to reliably establish the effect of the factor of fish stocking density in cages on the fishbreeding indicators of one-year-old pikeperch. Such results were obtained for the first time as part of the development of technology for commercial cultivation of pikeperch in cages on artificial feeds, which determines the novelty of the study. The results of the study can be used by fish farms engaged in commercial cultivation of fish in cages, including those with a natural temperature regime.