LAKE VICTORIA // It is just after dawn and a soft light is polishing the surface of Lake Victoria as Bernard Oluoch begins to paddle through a meadow. Thick blades of grass rise up to brush the patchwork sail of his narrow fishing boat. Three kilometres from shore, the floating meadow is so dense that the fisherman can only punt around it.
The field is woven together from hippo grass, a new invasive species that is threatening to choke the already besieged ecosystem of this magnificent lake. "It moves," he said, as though describing a sea monster. "You cannot go through it, you have to go around it." But it is not an easy problem to get around. The grass, which scientists are calling a "superweed", moves unpredictably on its floating mat of water hyacinth, cutting fishermen's lines and blocking their path home. Reaching into the muddy brown water, Mr Oluoch, 26, wrenches heavy, sodden roots and stems into the wooden yie, an African narrowboat.
"Look at it, it's like sugar cane." The weed is the latest predator in what has become an all-out attack on the second largest and the most populated lake in the world. And it is the latter that is at the root of its many of its chronic problems. Lake Victoria, spanning 68,800 square kilometres and three countries - Tanzania, Kenya and Uganda - is home to more than 30 million people, a population that depends on this body of water, even as they choke the life out of it.
Godfrey Ogonda, an environmental scientist with the Friends of Lake Victoria, describes the assault on the lake as an "integrated" problem. It sounds innocuous enough until he explains that deforestation upstream is speeding soil erosion and washing excessive nutrients into the lake; unplanned settlements are pouring untreated human waste into the mix; overfishing is chronic; climate change is reducing rainfall and raising temperatures; and invasive species are attacking the weakened ecosystem.
And that is not all. Massive hydroelectric dams have lowered the water level and more are due to come on line. Prof Ogonda works in a building that was erected right on the shoreline six years ago. That shore is now 150 metres away. Named in 1858 after Queen Victoria, the largest tropical lake in the world is the reservoir of the mighty Nile river and it is close to joining the ranks of dying lakes.
The first superweed to threaten the lake was water hyacinth, a gift from Belgian colonists downstream in Rwanda. Great mats of it fanned out across the waters prompting a crisis in 1997 and the intervention of the World Bank. Then the solution was a little and large double act of mechanical extraction and a tiny introduced insect, the weevil, which fed on the hyacinth. The formula worked; the hyacinth was dredged, eaten or sunk. But the soup of nutrients on which it fed did not go away. The hyacinth has come back and this time it has brought a new species with it - hippo grass. What scientists call a "successive weed", the coarse grass grows atop the hyacinth, much harder to extract and impervious to the weevils.
Seen from the air high over the banks of Entebbe in Uganda, the grass thickets form swirls in the currents like oil slicks. The crooked fingers of this green plague point in every direction. The organic blanket is preventing the cooling reflection of the sun's heat and helping to raise temperatures and evaporating the water, as well as shifting the Ph balance and encouraging poisonous algae blooms.
Dr Richard Abila, from Kenya's Marine and Fisheries Institute, has been watching the superweed with concern. "When hippo grass conquers the lake it's much heavier than hyacinth, it stops movement altogether," he said. "It also provides a habitat for snakes, mosquitoes, and we've seen a surge in malaria and bilharzia." He speaks wearily of an "endless battle" against superweeds but counts it as only one of the existential threats facing the waters of Victoria.
While he has watched the invasive species bloom, Dr Abila has seen fish stocks collapse. "Numbers of the once abundant Nile perch are down 90 per cent in the last five years," he said. The picture is similar for tilapia, catfish, lungfish and other species. This would not come as a shock to any of the more than two million fishermen on the lake. Of the five boats encountered on a morning's fishing, only one had caught more than a single fish. Its haul of two catfish would fetch no more than about 40 US cents (Dh1.4).
"Five years ago I would catch up to 70 kilos in a day," said Bernard, a fisherman. He holds up an immature Nile perch, the morning's only catch; it weighs less than one kilogram. Back on shore at Bunda beach there is a scramble of women with plastic buckets surrounding the yies as they come in, desperate for what would have once have been worthless: minute Nile perch or silverfish. Bernard points to the nets being used. They are mosquito nets, thousands of which were given away by aid groups to halt malaria and are being used instead to trawl the breeding grounds with their tight meshes.
The shallow nurseries close to the shore are supposed to be closed to fishermen in an effort to protect stocks and aid recovery. But with fewer and fewer big fish to catch and just as many mouths to feed, the law counts for little on these hungry shores. "In Kenya, Uganda and Tanzania, the fishermen are in competition to get as much as they can," said Dr Abila. Henry Ndede from the UN's Environment Programme is one of the international officials tasked with encouraging the countries that share the lakes to forge a common approach. He is clear what is at the nexus of its problems - poverty.
"It is a vicious cycle," in which poverty prevents planning, he said. The solutions are obvious, he said: reduce human and industrial pollution, impose a moratorium on fishing and reform agriculture around the lake. But these are "bitter pills" for already poor countries to swallow. "There is a disconnect between high-level knowledge and local decision making." For those who monitor the health of this vast lake, the outlook is bleak.
"If we left it alone the lake could recover within five years," said Prof Ogonda. But he does not believe for a second that will happen. "With human activity increasing, the lake doesn't have a future. "If you can't fish on it, you can't drink from it, you can't navigate or irrigate, is it still a lake?" * The National
