The state of planktonic and benthic communities of the skerry region of Lake Ladoga near fish farms

Abstract

The aim of this work is to assess the impact of trout farms on the ecological state of a freshwater body (Lake Ladoga) using hydrobiological parameters.The main methods of the study were sampling and processing of bacterioplankton, zooplankton, benthos; calculation of abundance and biomass of hydrobionts; analysis of taxonomic structure, species determinations, following standard procedures used in hydrobiology.As a result, a change in the quantitative development of bacterioand zooplankton, macroand meiobenthos communities, change in structure, simplification of taxonomic composition, decrease in species richness, appearance of species-indicators of toxic pollution in zooplankton and benthos communities under cages in the zones of influence of trout farms was revealed. Differences in the degree of severity of negative impact at the studied farms were noted, which can be attributed to the hydrodynamic factor, since one of the farms is located in conditions of greater flow compared to the other. Environmental quality assessment of planktonic and benthic communities showed the presence of negative impact of trout farms, the extent of which depends on the location of the farm and the degree of flow in the water area where the cages are located.