The diversity of benthic mollusks of Lake Victoria and Lake Burigi

Abstract

Molluscan diversity, abundance and distribution in sediments of Lake Victoria and its satellite lake, Lake Burigi, were investigated. The survey was carried out in January and February 2002 for Lake Victoria and in March and April 2002 for Lake Burigi. Ten genera were recorded from four zones of Lake Victoria while only three genera were recorded from Lake Burigi. In Lake Victoria the most diverse zone was Mara zone. The mollusca communities comprised of Bellamya, Gabbiella, Melanoides, Bulinus, Biomphalaria and Cleopatra (Gastropoda) and Corbicula, Eupera (Byssanodonta), Caelatura and Sphaerium (Bivalvia). Lake Burigi comprised of Melanoides, Bulinus and Biomphalaria. Melanoides tuberculata and Biomphalaria chaonomphala were the only two gastropods represented and widely distributed in the two lakes. Bivalvia constituting of Corbicula africana and Caelatura sp. were well distributed in Lake Victoria. The density of gastropods was higher in Speke gulf (1150 ind./m²) and Lake Burigi (1101 ind./m²) compared to remaining sampling zones in the main Lake (449 ind./m²; 369 ind./m²; and 60 ind./m² for Mwanza Gulf, Mara zone, and Kagera zone, respectively). The influence of physical and chemical conditions determining the molluscan species abundance and distribution in the two lakes and the role of mollusca in fish production is discussed.