Analyse de la biodiversité et de la production ichtyques dans trois lacs nord Africains : Merja Zerga (Maroc), Garaat Ichkeul (Tunisie) et lac Edku (Egypte)

Abstract

This survey first presents an inventory of fish species in the three studied sites. Altogether 17 fish species were found in Merja Zerga (Morocco), 25 species in Garaat Ichkeul (Tunisia) and 16 species in Edku lagoon (Egypt). Three fish groups live in these brackish lakes : sedentary fish, marine fish and freshwater fish. The second part of the study deals with the production of the different species. This production mainly rests upon Mugilidae and Anguilla in Merja Zerga and Ichkeul, while, in Edku, Tilapia is its principal component. In all these sites fish production seems to be decreasing these last years, because of over-fishing and essentially of the deterioration of the environmental factors, especially the hydrologic ones.