DYNAMICS OF THE PLANKTON COMMUNITY ROTIFERA, CRUSTACEA (COPEPODA AND CLADOCERA) FROM ONE HORIZONTAL AND THREE VERTICAL PROFILES IN THE KOZJAK RESERVOIR

The Kozjak Reservoir, as the largest artificial lake in North Macedonia, is characterized by high ecological and hydrological significance. This study focuses on the dynamics of zooplankton communities, specifically Rotifera, Crustacea (Copepoda and Cladocera), through research conducted along one horizontal and three vertical profiles within the reservoir. Zooplankton, as a key component of the ecosystem, was analyzed to determine its density and species diversity at different depths and profiles. The highest community density was recorded in the thermocline layers at a depth of 6 meters. During the summer period, Bdelloidea and Diaphanosoma populations dominate, while integrated samples show a significant presence of Eudiaptomus. Saprobiological analysis indicates β-mesosaprobic characteristics of the water, with values ranging from 1.2 to 2.6. These findings provide a basis for further understanding of the ecology of the Kozjak Reservoir and its biological productivity.