Interannual Changes in the Spring Zooplankton of the Pelagic Zone of Lake Sevan (Armenia) in the Course of Increasing Fish Biomass

It is shown that increasing fish biomass due to planktivorous whitefish Coregonus lavaretus L. in Lake Sevan leads to a reduction in the number of species, abundance, and biomass of spring ZP. In addition, quantitative characteristics of large species of Cladocera, Daphnia ( Ctenodaphnia ) magna Straus, and a decrease in the Shannon index value are changing as well. A decrease in the number of filter-feeding cladocerans contributes to a decrease in water transparency and an increase in the proportion of Rotifera in the total abundance and biomass of the community.