Plankton and Benthos of the Svir River Connecting the Largest Lakes in Europe

In May, August and September 2023, studies of phytoplankton, zooplankton, and macrozoobenthos were conducted at 7 stations of the Svir River. A total of 63 hydrobiological samples were taken. In general, the plankton and benthos of Svir River are clinical in nature. 2 species of relict crustaceans have been found: and . An invasive species of amphipod is also found throughout the river. The main factors determining the development of different groups of hydrobionts of the river are changes in its hydrological regime, the influence of runoff from Lake Onega and navigation. Along the entire length of the river, according to all studied groups of hydrobionts, the river belongs to the β-mesosaprobic zone, in summer, according to zooplankton, to the oligosaprobic zone. In the dammed areas along the macrozoobenthos – to the α-mesosaprobic zone.