Modern strains put Lake Victoria in critical condition
Pollution and overfishing in Lake Victoria have become so severe that scientists believe they threaten the health and livelihoods of millions of East Africans.
And researchers in the three countries bordering the world's largest tropical lake — Kenya, Tanzania and Uganda — largely blame governments and national agencies for failing to control the effluent and other waste that pours into the water every day.
John Omolo, 35, who has worked for two decades as a fisherman in the lakeside Kenyan city of Kisumu, says he now fishes only twice a week instead of every day, as he did when fish were still abundant just three years ago.
"The impact of the fall in fish stocks is felt on the dinner table, with tilapia selling at twice the price that it fetched three years ago," says the father of four. The price rise hits consumers in the Lake Victoria basin — home to 30 million people, a figure demographers expect to double in 15 years — but is not enough to compensate Omolo for his smaller catches.
Mike Obadha, fisheries officer in Kenya's Kisumu county, says that more than half of the 60,000 Kenyan fishermen who make a living from the lake fear being left jobless because of a fall in the stocks of all fish species, but particularly tilapia and Nile perch.
Fisheries managers estimate that more than 120,000 fishermen in the three countries bordering the lake make their living from its waters.
Wrecked breeding grounds
A survey published last year by the Lake Victoria Fisheries Organization (LVFO), a management body within the intergovernmental East African Community, showed that many fish breeding grounds have been destroyed by pollution and illegal fishing methods. Such techniques include the use of gillnets (vertical panels of netting), beach seines (nets deployed from the shore) and plastic monofilament fishing lines that can snare all kinds of wildlife.
The study found that the catch of Nile perch — which has become the dominant species since its introduction in the 1950s — dropped from 750,000 tonnes in 2005 to 337,000 tonnes in 2008. Similarly, the tilapia catch dropped from 27,100 tonnes to 24,800 tonnes over the same period.
Some fishermen exacerbate the problems by using poison.
Obadha tells SciDev.Net that fishermen operating from Nyamware beach in Kisumu County, for instance, were notorious for pouring endosulfan, an insecticide that is gradually being phased out around the world, into the water at night, to catch small fish such as dagga for local sale. He says poison is also used in Mwanza, Tanzania to incapacitate fish, causing them to float on the water where they are easy pickings for fishermen.
Continue reading at ENN affiliate, SciDev.Net.
Lake Victoria image via Shutterstock.