ECOLOGICAL AND BIOLOGICAL STUDIES ON THE BENTHIC MOLLUSCA OF CERTAIN SEGMENTS ALONG THE RIVER NILE WITII SPECIAL REFERENCE TO POLLUTION

Abstract

A survey for the freshwater molluscs was carried out along the River Nile, from sohag (450 km south Cairo) to Damietta and Rosette branches of the Nile, during the period from September 1993 to September 1994. Therefore, 31 sites, representing the various categories of irrigation and drainage canals, besides the Nile banks, have been chosen in 13 governorates around the Nile ecosystem, for studing their diversity, distribution, population dynamics and natural growth curves for the most common species. Moreover, some ecological parameters have been studied in the surveyed areas to investigate their effects on the distribution and abundance of the molluscan species.

A total of about 20 gastropod species have been recorded along the River Nile; 8 species were operculated and 12 species non­ operculated. 23 freshwater bivalves species have been identified along the River Nile, belonging to 5 families. 18 species ofthem are recording for the first time at the Rive Nile system in recent years.

Shell description, habitat, local and world distribution, status and key for identification were given for every species. Effect of ecological parameters and pollution on diversity, density and distribution of molluscan species were discussed.