Victoria’s Unwelcome Guests

Lake Victoria’s ‘evolving’ ecosystem has proved to be both a boon and a bane for those living along its shores. For starters, its waters are a haven for mosquitoes and snails, making malaria and bilharzia (schistosomiasis) all too common here. Then there are the Nile perch, introduced 50 years ago to combat mosquitoes, but which eventually thrived, growing to over 200kg in weight and becoming every fishing-boat captain’s dream. The ravenous perch have wiped out more than 300 species of smaller tropical fish unique to the lake.

Last but not least is the ornamental water hyacinth. First reported in 1986, this exotic pond plant had no natural predators here and has quickly reached plague proportions, even managing to shut down much of the lake's shipping industry. Millions of dollars have been ploughed into solving the problem, with controversial programs such as mechanical removal and the introduction of weed-eating weevils. The investment seemed to be paying off at first, with hyacinth cover shrinking for the first time in years, but the project has since halted over fears that the weevils were invading nearby agricultural fields. Scientists are still desperately looking for a solution as the hyacinth continues its relentless sprawl.