CONSERVATION OF THE AFRICAN GREAT-LAKES - A LIMNOLOGICAL PERSPECTIVE

The limnology of Lakes Malawi, Tanganyika, and Victoria is discussed w ith the objective of examining how the physical, chemical, and biologi cal properties of the lakes will determine the response of these ancie nt great lake ecosystems to human activities. Of the physical properti es discussed, large dilution capacities and long flushing times can ma ke the detection and removal of chemical pollutants in these lakes dif ficult The outflows of all three lakes are small because of high evapo ration losses, and as a result lake levels are responsive to climate c hanges that would alter evaporation; precipitation ratios. Increased n utrient input to these lakes will likely result in a decrease in the v olume of oxygenated water and available fish habitat. Plankton communi ty composition will also change, probably toward dominance by cyanobac teria While the effects of eutrophication on fish production are diffi cult to predict, changes in plankton composition would almost certainl y be accompanied by changes in fish community structure. Recent studie s of water chemistry and plankton productivity in Lake Victoria provid e evidence of possible eutrophication Because land use has a diffuse b ut potentially large impact on these lakes, conservation strategies mu st take into account human activities within entire drainage basins. T his requires cooperation between riparian countries and technological and financial input from the international community. An immediate nee d is the establishment of monitoring programs to determine the impact real or potential, of human activities around the lakes.