Modern state of plankton and benthos of large fishery water bodies in Vologda region

Abstract

The paper deals with monitoring results of phytoplankton, zooplankton and zoobenthos of the Sheksna reservoir, lakes Kubenskoye and Vozhe in Vologda Oblast in 2018–2022. The highest biomass of algae was recorded in lake Beloye (10.1 g/m3 ). In other water bodies, the average biomass made up 6.3–7.3 g/m3 . Diatom and cyanobacteria dominated in phytoplankton: diatom number was maximum in the river part of the Sheksna Reservoir, while cyanobacteria – in lake Beloye. Highly abundant Aphanizomenon flos-aquae induced annual water bloom of lake Beloye. Density of zooplankton was the greatest in Vozhe (131 thous. ind./m3 , 3.5 g/m3 ). Similar average biomass of zooplankton was noted in different parts of the Sheksna Reservoir (2.0 g/m3 ). In lake Kubenskoye, biomass reached 0.9 g/m3 . Copepoda formed the base of zooplankton number and cladocera – of biomass. In contrast to lake Vozhe (2.6 g/m2 ), zoobenthos in lake Kubenskoye was highly abundant (7.6 g/m2 ). The average biomass of zoobenthos in the Sheksna Reservoir accounted for 4–5 g/m2 . The dominant complex of zoobenthos included oligochaeta Limnodrilus hoffmeisteri, Tubifex newaensis, T. tubifex in all water bodies; chironomid larvae Chironomus sp., Procladius sp. – in the open sites; chironomids Endochironomus albipennis, Glyptotendipes gripekoveni, Cricotopus gr. sylvestris – in thickets. Chironomidae dominated in the Sheksna Reservoir and lake Vozhe, oligochaeta – in lake Kubenskoye.

Keywords

• phytoplankton
• zooplankton
• zoobenthos
• sheksna reservoir
• lake kubenskoye
• lake vozhe