Features of the formation of planktonic communities of small fish ponds depending on the quantitative, species and age characteristics of the ichthyofauna formed in them

: The article presents an analysis of materials obtained in the course of studies of hydrobiocenoses of small ponds of breeding and genetic center “Isobelino” (Molodechno district of Minsk region, 2nd zone of fish farming), stocked in a different ratio, depending on the experimental scheme used, by cyprinid fish, in particular, larvae of grass carp in monoculture at a density of 25 to 100 thousand individuals per hectare, larvae of the chinese roach at a density of 20 thousand individuals per hectare, yearlings of the ide in monoculture at a density of 6500 individuals per hectare and in polyculture with carp, grass carp, mottled carp and european catfish. In accordance with the nature of the formed ichthyocenoses, different feeding schemes were used. n the course of the research, it was found that the quantitative and taxonomic characteristics of phyto- and zooplankton communities largely depend on the structure and quantitative characteristics of the ichthyofauna formed in ponds. Higher quantitative indicators of zooplankton community development are observed in conditions of distribution of matter and energy flows along the detritus chain, in ponds inhabited by fish polyculture, more intensively involving organic matter of ponds in the food chain, higher rates of mineralization of organic matter and, accordingly, the return of carbon and biogens to the circulation of substances in the system are natural here. Low planting densities of the Amur white naturally exert significantly less pressure on zooplankton communities compared to variants with higher planting densities, therefore, higher biomass and zooplankton production is achieved, as well as potential fish production due to plankton communities. The products of planktonic communities are most effectively converted into fish products in ponds where the ichthyofauna is represented by a polyculture of pond carp fish. The potential fish productivity here reached 306,56 kg per hectare, while 300,0 kg per hectare of fish products could be obtained due to zooplankton.

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