DISTRIBUTION AND SALINITY RANGES OF ZOOPLANKTON ORGANISMS AT EL-FAYOUM DEPRESSION (EL-FAYOUM-EGYPT)

Abstract

KEY WORDS; Salinity ranges, Zooplankton, Qaroun and Wadi EL-Rayan Lakes, EL-Fqyoum depression. (ReceivedFeb.25,1998) ABSTRACT D istribution and salinity ranges of the different zooplankton species at Ei Fayoum depression (El Wadi drain, Wadi El-Rayan Lakes, Fish Farms, Lake Qaroun, and EMISAL company ponds were discussed 18 species of Protozoa, 39 of Rotifera, 10 of Cladocera, 9 of Copepoda and only one Branchiopod were found, Moreover, the Tardigrad Macrobiotus macronyx and the Qstracod Cyprideis torosa in addition to the larvae of some benthic invertebrates were also obtained. Water of the studied area had a salinity range from 1.7 to 322 %o. In distribution, the species numbers were mostly decreased with increasing salinity. Some species werefoundtobeeujyhalineas5racA/o«usj7//caft'to (1.7-127.7 %o), Hexarthra oxyuris (2.5-73J%o),Keratellatropicaand!C valga { 1.7-42 %o for the two species), while all the Cladocera were stenohaline. On the other hand, thirteen species were endemic to its area.