On the productivity and ecology of zooplankton and its role as food for fish in some lakes in Central Finland

The study deals with the influence of some physical, chemical, and biotic factors upon the species composition, biomass, and production of zooplankton in several Finnish lakes. Different groups of zooplankton species are separated according to their relation to eutrophication and pollution caused by sewage and wastes from pulp and paper mills. The zooplankton biomass, estimated with the mean volumes of different species and stages, is considered in relation to eutrophication and pollution, and also to the production of phytoplankton. Some comparisons are made between different methods of estimating production. The significance of vendace (Coregonus albula L.) and smelt (Osmerus eperlanus L.…