Diversity and stability of fish stocks in Lakes Victoria, Kyoga and Nabugabo after establishment of introduced species

Abstract

In the first half of this century, Lakes Victoria, Kyoga and Nabugabo had a diverse and similar native fish fauna (Graham, 1929; Worthington, 1929; Cambridge Nabugabo Biological Expedition, 1962). The fisheries of these lakes were based on about 14 fish taxa of which two were tilapiine cichlids; Oreochromis esculentus and O. variabilis were the most important. The haplochromine cichlids were represented by more than 300 species in Lake Victoria, more than 99% of them endemic (Greenwood, 1974; Witte et al., 1992a, b). These formed at least 80% of the demersal fish stocks in Lake Victoria up to the 1980s (Kudhongania and Cordone, 1974; Okaronon et al., 1985). Haplochromine cichlids were also abundant in Lakes Kyoga and Nabugabo (Worthington, 1929; Cambridge Nabugabo Biological Expedition, 1962).