HUMAN IMPACTS ON THE AFRICAN GREAT-LAKES

The African Great Lakes are important sources of fishes and water for domestic use, are used as avenues of transport, and receive agricultur al, domestic and industrial effluents and atmospheric residues. Some o f these lakes have speciose fish faunas of great interest to science. The catchment areas of some of the lakes are highly populated and user conflicts have increased the demands on the lakes' resources. There h ave been drastic reductions in fish stocks in most of the lakes due to overfishing. Introductions of new fish species, though followed by in creases in fish catches, have been accompanied by a decline and in som e cases extinction of native fish species. Some of the lakes have been invaded by the water hyacinth, Eichhornia crassipes. Agricultural act ivities, deforestation and devegetation of the catchment areas have in creased siltation, and led to loss of suitable habitats and biodiversi ty. There are increased nutrient inputs from agriculture, sewage and i ndustrial discharges and combustion processes which can cause eutrophi cation. There are also increased threats of toxic pollution from indus trial waste discharge, mining, pesticides, and oil residues and spills . Climatic changes may also affect thermal stability of the lakes. The se factors threaten availability of dietary protein, clean water and b iodiversity. National and international efforts are required to manage the fisheries, guide the introduction of exotics, conserve biodiversi ty, control the water hyacinth, control eutrophication, reduce input o f contaminants and manage climate change.