[Hydrobiology of the hydrographic net of Ichkeul basin (Tunisia)]

This study is a morphological, physical, chemical and biological comparison of the main streams of the Ichkeul basin. The sectors investigated on these streams present a good physical, chemical and biological quality. The marine influence of the Mediterranean Sea via Lake Bizerte and Lake Ichkeul is greater in Oued Melah and Oued Sejnane than in Oued Joumine, which has a more continental character. These differences appear in the physical, chemical and faunal aspects of the rivers, and mostly during periods of drought. The newly-constructed dam on oued Joumine is beginning to have an impact downstream, by causing an increase in salinity and conductivity, mainly in summer.