State of ecosystem of Lake Khedo (Western Karelia) in conditions of fish breeding

The article highlights the analyzes of ecosystem Lake Khedo (Republic Karelia) under conditions growing anthropogenic load caused by using lake for breeding trout in fish cages based on proper and literature data. Comparative analysis hydrochemical data before operation farm (until 2005) after showed a twofold increase water color (70-150°), which indicates an increased content organic pollutants (humus, peat, silt). Also reservoir there are nitrogen phosphorus compounds. Previously, concentration total did not exceed 0.01 mg/l, today it reaches 0.02 mg/l. main factor contributing to satisfactory state is high flow rate, due most biogens flown outside lake. hydrobiological indicators (phytozooplankton zoobenthos) presented. It has been stated that if earlier corresponded mesohumous oligotrophic type, at present initial level mesotrophy, probably facilitated long-term cage cultivation aquaculture object. In terms abundance organisms trophic levels, corresponds α-mesotrophic type. inhabited 8 species fish, valuable ones include whitefish Coregonus lavaretus (L.) vendace albula (L.). results research made possible clarify production commercial trout, amounted 300 tons per year doesn’t biogenic load. Recommendations timing regular ecological expertise adjustment volumes given