Studies on Fish Populations in Jebel Aulia Reservoir.

Abstract

Fish populations in the northern part of the White Nile have been studied. Two stations were chosen for sampling north and south of Jebel Aulia dam. Monthly sampling was carried out form each station during 1976-1977. Thirty three species have been identified from the study areas. Of these, twelve species occurred regularly, the remaining twenty-one were encountered occasionally. Higher yield with larger fish was often recorded from the station above the dam. The species composition showed that there was a decrease both in number of species and size of fish in the study areas during this investigation. Seasonal fluctuations of the different species were affected by the Nile regime and the presence of Jeble Aulia dam. Synodontis schail (Bloch-Schneider, 1801), Hydrocyon lineatus (Bleck. 1862) and Labeo niloticus (Froskol, 1775) were found to be the most common species. Feeding habits varied among the species. Some were omnivorous, showing no apparent food selection, others were more selective, Variations of food with age has not been detected. The age composition showed that smaller and middle age – groups dominated the catch. Fish abundance and the chemical characteristics of the water showed no direct correlation.