Taxonomical Composition and Abundance of Macrozoobenthos in the Sheksna Reservoir at the Begining of Xxi Centuary

According to the results of observations in 2016–2017, 126 species were identified in the macrozoobenthos of the Sheksnareservoir. Heterotopic and homotopic fauna were represented in the taxonomic list in approximately equal proportions (about 50%). Species composition was dominated by larvae of chironomids (38%), oligochaetes (20.6%), and mollusks (19%). The average benthic biomass of the Sheksninsky reservoir as a whole was: ~6.6 g/m2; in the river part ~5 g/m2; in the lake Beloje ~7 g/m2. Significant interannual fluctuations in the average abundance and biomass values in the deepwater zone of the lake Beloje have been revealed. A decrease in the average macrozoobenthos biomass was noted in all parts of the Sheksna reservoir, compared with the end of the twentieth century.