Conservation of fish species diversity in the Victoria and Kyoga lake basins

Abstract

Fish species diversity in lakes Victoria and Kyoga has declined and some species, especially of haplochromines and Oreochromis esculentus are believed to be extinct. A survey was carried out in a number of satellite lakes and an inventory made of the existing fish species, their relative abundance and distribution. The lakes studied included the Kyoga minor lakes, Nabugabo lakes, the Koki lakes and L. Wamala. Various habitats within the main lakes Victoria and Kyoga were also surveyed. Various stations along rivers Nile and Sio were also sampled. A total of twenty-one fish taxa were recorded from Kyoga minor lakes as compared to eighteen recorded from Lake Kyoga. Lake Nyaguo had the highest number offish taxa (14), followed by lakes Nakuwa (12), Nawampasa (II), Lemwa (10), Agu (9), Kawi (8), and Gigati (7).The number of haplochromine species was highest in L. Nawampasa (23) followed by lakes Gigati (18), Agu (11), Nyaguo (10), Lemwa (8) and Nakuwa (2). Fourteen fish taxa were recorded from the Nabugabo lakes, the highest number being from L. Nabugabo (13) followed by lakes Kayanja (11) and Kayugi (7). Four haplochromine species were recorded from Nabugabo lakes From Koki lakes eight fish taxa were recorded, Lake Kachera having a higher number of species (8) than L. Mburo (6). A total of 9 fish taxa were recorded from L. Wamala, with only two haplochromine species Overall, twelve fish taxa were recorded from L. Victoria. Twenty-two haplochromine species were recorded from the lake. The habitats with rocky outcrops and macrophyte cover were found to have the highest number of fish taxa. River Sio had a higher number of fish taxa (17) than R. Nile (7). Results show that some of the fish species that have disappeared from lakes Victoria and Kyoga are present in the satellite lakes and rivers surveyed. Inshore areas with aquatic macrophytes and rocky habitats were also found to be important refugia for the endangered fish species. Some of the satellite lakes and the selected habitats within the main lakes should therefore be protected for conservation of fish species diversity