 Additionally the area is a habitat for many species of animals including the hippopotamus ("Hippopotamus amphibius"), Nile crocodile ("Crocodylus niloticus") and many other mammals, amphibians, reptiles and the invertebrate communities.While stocks of Nile tilapia in the lake are now low, the decline of this species has been mirrored by the success of another, the marbled lungfish ("Protopterus aethiopicus") which was introduced to the lake in 1974 and which now provides the majority of fish from the lake.Water levels have been reduced by droughts and over-irrigation.