African Unification Front
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POLLUTION IS CHOKING COMMUNITIES ON THE SANGO BANK
AFRICA'S LARGEST LAKE IS THE WORST ECOLOGICAL FAILURE
Satelite amage of Lake Victoria showing location of major cities
For 10 years, the water hyacinth has been a major problem. It threatened to choke the livelihoods of those who survived on the bounty of Lake Victoria.
Lake Victoria is the second largest lake in the world. It has an area of 68000 km2. The catchment area is 193,000 km2. The fisheries of the lake was once multispecies with the cichlids forming the bulk of the catches. In the 1970s a trawling fishery was introduced to tap the haplochromines for fishmeal production. In the early 1960’s Nile perch (Lates niloticus) was introduced into the Lake. The fish biodiversity has since disappeared and the multi-species fishery has now been reduced to a three species fishery of Nile tilapia, Nile perch and a sardine (Rastreneobola argentea). The reduction of haplochromines has drastically altered the food web with impacts on plankton dynamics and possibly water quality.
Although the present fishery is a three species fishery the total landings has risen from 250,000m tons in 1960s to 400,000-500,000 m tons now. However, the fishery is under threat from illegal fishing practices, localised overfishing and environmental factors including water hyacinth and pollution.
According to experts working with the Lake Victoria Environmental Management Programme and the Kenya Agricultural Research Institute (KARI), 80 per cent of the weed has been destroyed by a combination of beetles introduced into the lake, and Sh100 million mechanical harvesting project funded by the World Bank. However, the weed has a habit of regenerating rapidly even after 15 years.
But still, the water hyacinth has devastated the economy of the towns like Kisumu on the lake shore. Since the weed first appeared, it has spread so fast and so thickly that it has restricted the fishing industry and threatens most forms of marine life. Its sheer profusion has meant that the lake is dying.
The economy of the lakeside city of Kisumu was devastated
Besides occupying vast expanses of the lake's surface, the weed, which is a parasite on marine life, has also been responsible for imbalances in the ecosystem. Previous attempts at harvesting it failed because the harvesters cut the leaves and stems, leaving the real parasite floating below the surface, only for the leaves to sprout again.
Mechanical harvesting has led to even more problems because the shredded hyacinth, dropping to the bottom, has only acted as nutritious fodder for hippo grass, papyrus reeds and other weeds, now taking over the deleterious functions of the hyacinth. The American firm contracted to harvest the weed exactly one year ago ignored the warnings of scientists against dumping the shredded weed.
Organizations that are involved in trying to save the lake include:
Lake Victoria Fisheries Organization (LVFO);
Fisheries Research Institute (FIRI);
Lake Victoria Fisheries Research Project(LVFRP);
United Nations Environmental Programme (UNEP);
International Union for Conservation of Nature (IUCN);
International Development Research Council (IDRC);
UN Educational, Scientific & Cultural Organization (UNESCO);
Kenya Agricultural Research Institute (KARI)
Lake Victoria Environmental Management Project (LVEMP);
International Development Research Council (IDRC);
World Bank (WB);
Canadian International Development Agency (CIDA);
UN University/International Network on Water, Environment and
Health, Canada (UNU/INWEH);
University of Makerere;
University of Zurich;
Nile Breweries;
Fisheries Society of Africa (FISA);
Food and Agricultural Organization (FAO)
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