Impacts of construction of the new Assiut barrages on zooplankton community structure inhabiting Nile River at Assiut Egypt

The present study was carried out during establishing the new Assiut barrages and hydropower plant project at the city of Assiut, Upper Egypt during the period of one year 2012. The present study was designed to estimate the implications of construction of the barrages on zooplankton community structure at the working region. The new barrages are being implemented across the Nile River and located away from the old one about five hundred meters. The sites of sampling zooplankton included 8 sites; four of them are situated upstream of the old barrages and the other four are located downstream after the old barrages around the construction area. The study recorded eighty zooplankton species at the investigated sites during the period from January to December 2012. The composition of zooplankton showed differences between up and down stream sites. The sites located upstream of the old barrages have similar compositions (79 taxa in each site) while sites located downstream have different compositions (76, 63, 72 and 68 taxa) were recorded in sites 5, 6, 7 and 8; respectively. The highest value of total abundance of zooplankton was (272 Indv/m3) recorded at upstream while the highest value recorded at downstream was (96 Indv/m3). Taxa richness reached the highest peak value (42 taxa) at upstream and (24 taxa) at downstream. Shannon- wiener’s diversity index ranged between (2.74) and (2.69) at upstream while it ranged between (2.45) and (2.59) at downstream.