THERE are now clear signs that water hyacinth will have more devastating consequences on marine life and that of human being in Lake Victoria.
As one walks along the shores of Lake Victoria they are likely to see a big number of such weeds that seem to have resurfaced in the recent past.
Fishermen and other local residents feel that the water hyacinths are nothing more than a major threat to their daily survival. The fishermen in Kagera Region have expressed concern saying the weed has blocked fish landing beaches and sometimes harboured mosquitoes, snakes and other dangerous marine organisms that prefer to hide in such places.
Observers say the most affected areas included, Goziba, Bumbire, Nyaburo and Musira, on the Lake Victoria Archipelago. "In just a few years ago these weeds were almost contained, and at the moment we see them just resurfacing along the shores of the Lake Victoria.
I think it is time the authorities found permanent solutions to the problem," says one Bukoba resident, Kairuki Rutashobwa. In Mwanza Region too, the deadly weed is extending its tentacles. The most affected areas include, Makongoro, Sweya beach, Kirumba, Ilemela, just to mention a few.
Experts say that fishing and other related activities on Lake Victoria are under threat following renewed invasion by the water hyacinth. Water hyacinth, the weed which once choked Africa's greatest lake waters, threatening the lives of other organisms and cutting fish production, is back again.
Experts say in 1997, for example, the water weed covered at least 2,000 hectares of the Lake before it was reduced by 80 per cent nine years later, through spirited control measures that have been done by LVEMP in a joint collaboration with other stakeholders.
Since then, the weed has been spreading due to continuous inflow of water hyacinth in Kagera River and availability of nutrients, which favour proliferation of the weed in the lake. Studies have suggested that the water hyacinth was introduced in Africa in 1879, only to find its way to the Africa's largest Lakes 110 years later.
The plant spread started first along the shorelines, forming thick mats that covered an estimated area of 20,000 hectares (about 77 square miles) of the lake by 1998. By 1995 around 90 per cent of the Ugandan coastline was covered by the plant.
It covered substantial areas of the shore, particularly in Uganda, blocking waterways, disrupting hydropower, and decreasing the profitability of fishing. Hyacinth also provided refuge for some fish species from the introduced Nile Perch.
It largely disappeared from the Lake in the late 90s, perhaps, but not clearly, due to the introduction of a weevil used for biological control. But in December 2006, according to different satellite images taken, the water hyacinth had returned. The die-off of native plants affects fish and other aquatic animals, according to studies.
Water hyacinth clogs irrigation canals and pipes used to draw water from the lake for cities and villages on its shoreline. Besides, the plants impede water flow, creating abundant habitat for disease-carrying insects like mosquitoes. The weed can also sap oxygen from the water until it creates a 'dead zone' where plants and animals can no longer survive.
Hyacinth is a freefloating aquatic plant native to tropical South America. It can grow to a height of three feet and has thick heavily branched fibrous roots. It moves seasonally with the waves from bay to bay, blocking waterways and affecting aquatic life as it sucks oxygen from water, say experts.
Experts add that the problem of invasive aquatic plant is particularly pronounced in warmer parts of the world. One of the worst is water hyacinth (Eichhornia crassipes), which blankets the surface of the water and grows at a very fast rate.
"The shores of Lake Victoria are now choking, becoming completely solid with water hyacinths," said Shana Greene, founder and director of Village Volunteers, a Seattle-based organization that partners with rural communities around the world to create environmentally sustainable solutions for hunger and poverty.
Lake Victoria is the largest freshwater body in Africa, providing a lifeline for more than 5,000,000 people living in rural communities on or near its shore. The lake is their main source of water for bathing, drinking and cooking, and its fish populations provide both protein and an income for families.
Many of the fish, including members of the lake's large cichlid population, are endemic found nowhere else on earth. Water hyacinth forms lush green carpets that raise the water's temperature and simultaneously reduce sunlight, depleting oxygen levels and blocking access to the shallow waters.
This can result in tangled fishing nets and even trapped boats. "Fish are an important source of protein for local communities," Greene said. "The warmer water harbours all sorts of diseases, making it less safe for drinking." The plants also make an ideal hiding ground for disease-carrying snails and venomous snakes.
As a result, Village Volunteers is helping local communities to fight back and turn a potentially devastating situation into a possible financial boon. "Water hyacinth is actually a really great raw material for so many things," Greene said.
"We are helping communities in Kenya to harvest it and use it to create tools for the home and to sell. We are making it into fuel briquettes for cooking fires and turning it into a very effective fertilizer." Village Volunteers are also helping local entrepreneurs produce chairs, baskets, and other pieces of furniture that can be made by weaving together the tough stems and leaves of the hyacinths.
"The water hyacinth invasion was potentially an overwhelming problem, but it is now being developed into a business," Greene said. "By using only locally available materials and labour, with oxen helping to harvest the hyacinth for example, so the end result is largely self-sustaining."
In addition, while the villages on the shore of the lake cannot eliminate water hyacinth completely, they are clearing it away from the shores near where they live, serving to improve the quality of their immediate water supply, as well as the environment for the fish populations on which they depend.