Eutrophication of Water Bodies and Control of This Process with the Use of Zooplankton and Planktophage Fish

Abstract

The study was carried out in a number of small water bodies within the boundaries of Moscow. In these water bodies, regular and mass blooming of cyanobacteria and green algae was recorded. Due to the long-term repeated spawning during the summer, juvenile fish of various sizes were constantly present in the pond. They mostly consume large-size zooplankton. Because of this, the dimensional structure of the population shifts towards smaller species. Simocephalus vetulus was recorded in the water body only once (July, 24). Its number was as small as 0.1 spec/L. After that, up to the end of the study, it was not observed in the pond, although it developed very well in an experimental ecosystem (into which it had entered from the water body). In an isolated flow-through ecosystem (in the absence of fish), the number of S. vetulus in August reached about 9 thousand spec/L. It was not observed in the pond because of its grazing by fish.