Biomass Dynamics of Pelagic Crustacea in Lake Ohrid, Republic of Macedonia, in the Period 2000-2009

The trends in biomass dynamics of the Crustacea (Cladocera and Copepoda) in the pelagic zone of Lake Ohrid were analysed through the period 2000-2009. The Copepoda contributed to the total Crustacea biomass by a major ratio. The values of the Crustacea biomass were the highest in the summer and autumn periods, when the values of the Copepoda and Cladocera biomass were similar. Considerable increase in the Crustacea biomass was recorded during the summer period 2004, which resulted from the relatively high biomass values of the Copepoda, especially the Calanoida. High values of the Crustacea biomass were found also in the summer and autumn period 2008-2009, when the biomass of the Cladocera considerably increased in comparison with the other studied periods that imply considerable changes in zooplankton community.