STRUCTURAL CHARACTERISTICS OF BIOTIC COMMUNITIES OF THE VYGOZERSKOE RESERVOIR LITTORAL ZONE
For the first time during the past 40 years we studied the structural characteristics of planktonic and benthic communities (phyto- and bacterial plankton, phytoperiphyton, meio- and macrozoobenthos, higher aquatic vegetation), and the food spectrum of fish in the rocky littoral zone of the Vygozerskoe impounding reservoir. We found a significant difference in the structure of these communities between the northern and southern parts of the reservoir. The maximum biomass of phytoplankton was recorded in Sennaya Bay -6.5 mg/l, due to the development of the colonial diatom alga Tabellaria flocculosa, an indicator of low concentrations of nutrients and oligotrophic conditions. The relatively high biomasses of phytoperiphyton (green and blue-green algae) and macrophytes in the southern part of the reservoir evidence the eutrophication process. Benthic organisms are a food for perch, roach and whitefish, but the low biomass of meio- and macrozoobenthos (2-3 g/m <sup>2</sup>) in the littoral zone of the reservoir causes the fish to feed on a mixed diet, utilizing drift and planktonic crustaceans as a food.