Abstract :
Four stations were selected to carry out this study. Two stations were located at Al-Tharthar- Euphrates canal, while the remaining two were located at Euphrates River, to know the effect of Al-Tharthar-Euphrates canal on the composition and diversity of zooplankton in Euphrates River. In all the studied stations the total zooplankton showed high densities in autumn and low densities in summer. The statistical analysis results showed significant difference between station 3 and station 4 in Euphrates River. Rotifera were the dominant group quantitatively, followed by Copepoda and Cladocera. 52 taxa of zooplankton were recorded, 32 taxa belonged to Rotifera, 12 to the Cladocera and 7 to the Copepoda. The results also showed that the Rotifera: Keratella cochlearis and Brachionus calyciflours, the Cladocera: Bosmina longirostris, the Copepoda: nauplii were dominant in both canal and Euphrates River. The biodiversity indices indicated high fluctuated with seasons. The results also showed that the species composition in the Euphrates river were not affected by the canal water. The higher values of uniformity index of different zooplankton groups indicate there is no ecological stress on zooplankton in the study area.
