Macroinvertebrate fauna of water hyacinth in the Kenyan waters of Lake Victoria.

Abstract

The macro-invertebrate fauna on water hyacinth in Kenyan waters of Lake Victoria was surveyed by collecting samples from 5 major ecological zones of the lake. Insecta, Oligochaeta, Hirudinea, Arachnida, Gastropoda and Bivalvia, totalling 130 taxa, were collected. The highest densities of invertebrates were observed in the lakeward zone of the fringe and the free-floating rafts. Insecta dominated in species richness, abundance and biomass in all 5 habitats. Adult Coleoptera were more abundant on the landward side of the water hyacinth fringe than on the lakeward side and rafts. Distribution of the organisms was mainly influenced by dissolved oxygen and dissolved ions. Molluscs that are vectors of various flukes causing domestic livestock and human diseases (e.g. schistosomiasis) included Bulinus globosus, Bulinus nasutus, Bulinus ugandae and Biomphalaria pfeifferi. Lymnaea natalensis, a vector of flukes which cause fascioliasis, was observed in the littoral zone. Other vectors of human diseases found on water hyacinth were larvae of mosquitoes of the genera Anopheles, Aedes, Culex and Culiseta. From authors' summary. KEYWORDS: TROPAG | Eichhornia crassipes | aquatic plants | Eichhornia crassipes | hosts | invertebrates | useful insects | vectors | human diseases | health | KENYA | Lake Victoria.