AN OVERVIEW OF FRESH-WATER BIODIVERSITY - WITH SOME LESSONS FROM AFRICAN FISHES

As the twentieth century draws to a close, arguments about the viabili ty of continued population growth, agricultural development, industria lization, and exhaustive resource use are intensifying. In perhaps no scientific arena are these issues more urgent than in the management o f freshwater usage and aquatic conservation. As human populations cont inue to burgeon, the limits of the Earth's freshwater resources are re vealed more and more in the increasingly intense conflicts between hum an consumptive usage and the maintenance of aquatic health and biodive rsity. Despite the fact that freshwater habitats comprise less than on e-hundredth of a percent of the Earth's water, the rivers, lakes, and wetlands of the planet harbor exceptional concentrations of biodiversi ty. While globally the true degree of aquatic impoverishment is largel y unknown, these losses are doubtless already great. Much attention ha s been focused on worldwide losses of terrestrial biodiversity, partic ularly in tropical ecosystems, and when considered at all, the situati on in freshwaters has tended to be something of an afterthought. Howev er, it is increasingly evident that the pending ''crisis of freshwater '' will set the agenda regarding future development.