The water hyacinth in Lake Victoria spread to 1,441 more hectares within four days, according to satellite images released by a State agency yesterday.
The images by the Kenya Marine and Fisheries Research Institute (KMFRI) showed the area covered by the weed increased from 6,142 hectares on February 11 to 7,583 hectares on February 15.
This is likely to be demoralising, especially for the people who directly depend on the lake for their livelihood, after statistics indicated that the area covered by the weed had reduced significantly.
The figures had raised hopes for business people, including fishermen, people who engage in boat riding and general water transport, that the shores would soon be clear again to enable them to carry on with their activities.
Water transport in Lake Victoria has been hampered as ferries no longer dock at the Kisumu port, thanks to the presence of the weed.
Water hyacinth, an invasive plant species native to South America, has become a major problem in Lake Victoria and has negatively affected local ecosystems.
KMFRI has attributed the rapid spread of the hyacinth to pollution of the lake, causing the weed's seeds to germinate faster.
Wind also facilitates the spread of the weed by scattering its seeds.
Christopher Aura, the deputy director of freshwater systems research at KMFRI, told The Standard yesterday that some of the weeds were rotting and sinking to the bottom of the lake.
This could explain why the area covered by the weed reduced at some point even as national government efforts to remove it continued to gain momentum.
“Areas adversely affected by the weed include beaches in Kisumu as well as Asembo Bay, Madundu Beach, Kopiata Beach, Kendu Bay and Rakwaro Beach in Osodo Bay,” said Dr Aura.
At the beginning of the year, the weed had covered 10,758 hectares of the lake. This went down in the course of January to 9,020 hectares, 8,174 hectares and later 6,142.
Experts say when the conditions are right for its growth, the area covered by the water hyacinth can double within 15 days.
In December last year, the area the weed had covered hit a record 17,372 hectares, paralysing almost all activities in the lake during the festive season.
Some experts have said manual removal of the water hyacinth could be the only solution.
Opposition leader Raila Odinga recently criticised scientists for failing to find a lasting solution to the menace.
"At this rate, we will not get anywhere. The scientists will continue to give us theories yet the weed is here. Their theories do not help,” Raila said.
His sentiments were echoed by two Cabinet secretaries - Keriako Tobiko (Environment) and Raphael Tuju (without portfolio).
The fight against the weed is being led by Lake Victoria Environmental Management Programme scientists.
Efforts to remove the weed have been costly. Equipment purchased at a cost of Sh81 million to facilitate removal of the weed has been lying idle at the Kisumu port.