A GENERAL SURVEY OF THE HELMINTH PARASITES OF SOME FISHES FROM LAKE NASSER AT ASSWAN, A.R. EGYPT

The helminth parasites, were surveyed from some fishes of lake Nasser at Assuan. Out of fish examined, (55.88%) were found infected with one or more species of parasites. How ever, mixed Infections were frequently met with. Every species of parasite may infest more than one species of hosts. Out of the fish examined, 8.51% were found harbouring trematode parasites, 4.65% harboured cestodes, 47.66% harboured nematodes, 10.52% har boured Acanthocephala. The highest incidence of infection with trematode parasites was found in Tetraodon fahaka (92%), the maximum incidence of cestode parasites was 65.71% in Clarias anaguillaris, the maximum incidence with nematode parasites was found in Hydrocyon forskalli and H.lineatus (95.2% & 94% respectively). The maximum incidence with the parasites followed to the Acanthocephala was 80% in Lates niloticus. The highest percentage of trematode parasites (24.93%) occured in the intestine, all the cestodes and Acanthocephala were found only in the intestine; and the highest percentage of nematodes occured in the muscles (59.55%) and fins (40.45%). Out of the trematode surveyed, 5 species were briefly described, figured and discussed in details, two of which were found to be new species namely: Astiotrema lazeri from the intestine of Clarias lazera, and Allocreadium aswanensis form the intestine op Barbus bynni. Out of the cestode surveyed, 4 species were studied in details, one of which was found to be new namely; Marsypocephalus aegyptiacus from the intestine of Clarias lazera.