Vokhtozero - water reservoir of cage culture fishery

The article is concerned with hydrological and hydrochemical regimes of Lake Vohtozero and its biological resources (aquatic plants, zooplankton, zoobenthos and fish fauna). The lake belongs to cold-water reservoirs with significant temperature stratification in summer. The average monthly temperature from May to October ranges from 10,9 to 18,7 °C; gas regime is friendly. Due to favourable water conditions for fish growth, a trout cage farm was organized in the area in 2007. The fish fauna of the lake consists of whitefish, cisco, peled, trout, pike, burbot,ruffe, perch, roach, and ide. In summer, the fish of the lake lives off voluminous leftovers of pelleted fish food gravitated in the zone around netcages. In autumn, the fish migrate from the netcage area to other parts of the lake. The fish food leftovers concentrate in the bottom layers of the water by this increasing the amount of particulate matter and nitrogenphosphorus compounds. No significant differences in the chemical composition of the water in the netcage area, in the range from 100 meters up to 4,5 km.(control area) were revealed. Compliance with all netcage fish farming requirements secures long-term capacity of the fish farm.