DISTRIBUTION AND ABUNDANCE OF ZOOPLANKTON IN THE RIVER NILE,EGYPT

Zooplankton is known to form an important component of the biological communities in large rivers due to their high abundance and ability to cycle nutrients through the aquatic environment. Little is known about these communities in the River Nile, so the present study was designed on samplingZooplankton in the River Nile (main body) and its two branches, Rosetta and Damietta, along four seasons of the year 2009. During the investigation period, Rotifera represented the most dominant species recording 54% followed by Protozoa, Cladocera, Copepoda, and Meroplankton with ratios of 17%, 15%, 9%, and 6% respectively. There were marked seasonal differences between individual species in the main body of the river and its two branches.