By Jean-Pierre Afadhali*
Despite water Hyacinth’s reduction in recent years, Kenya is dealing with the invasion of the water weed in Lake Victoria, the largest tropical freshwater lake in the world shared with its neighbors Tanzania and Uganda using various methods that include mechanical, manual and biological. But efforts to eradicate it have been complicated by its mobility as it moves within the lake influenced by the weather patterns, water current amid other management challenges.
The floating aquatic plant is believed to have first reached Lake Victoria in the 1990s, floating down the lake's western tributary, the Kagera River, in East Africa. It’s been a major problem for communities in the Lake Victoria basin for decades as it blocks navigation in the lake, hindering fishery, tourism and access to other resources that are important for communities’ livelihood. The water weed is even considered as a curse by some people who depend on the lake for their livelihood.
The fact that water hyacinth is seasonal and floating on water has complicated efforts to eradicate it. The people familiar with the weed issue said it is much highlighted when it is available at a given side of the lake making it hard to find a sustainable solution. For instance, when Pan African Visions visited the lakeside city of Kisumu in February it was not visible. However, local residents said, in the past it has covered the lake to the extent that they couldn’t even see the water. When it is available the impact is seen locally the effects on transportation in the lake are immediately felt.
“There is always hyacinth at different points and then when the wind blows you will find that water hyacinth canopy moves from the pier,” said Otieno Nyagutu Michael, chairperson of the community-based organizationMagnam Environment Network. “So, when it moves away from the pier it is more of forgotten.”
Riparian countries have deployed various efforts to deal with the floating water weed. In Kenya one of the approaches used to control the weed is mechanical through water hyacinth harvester machine. However, the methods appear to have not yielded expected results, despite the high cost of implementation. According media reports and environmentalists, some expensive machines the country bought did not work properly. Recently Kisumu county in western Kenya received a water hyacinth harvester worth $ 316,000 from the Indian government. It is expected to boost efforts on the long fight against invasion of the notorious aquatic plant.
Speaking at the function to receive the harvester machine, the governor of Kisumu county Prof. Peter Anyang’ Nyong’o noted that the weed has for the past thirty years has been slowly but steadily sucking life out of the lake which is a source of livelihood to millions of people in the Lake Region Economic Bloc and the three East African Countries.
Despite the efforts of the Kenyan government and its partners in the use of mechanical ways that is costly to deal with the invasion of the water weed, environmentalists like Otieno say there is a lot that still needs to be done. “I happen to be in Kisumu, there have been attempts but I would not call them very positive, because we have not seen much actually on the lake,” he said. “Unfortunately, this has been aided by the fact that water hyacinth moves with the wind.”
Data from Kenya Marine and Fisheries Research Institute (KEMFRI), which monitors hyacinth coverage, show the weed coverage in Kenyan waters has considerably reduced in recent years. As of December 2022 the coverage was 1,265 ha of Kenyan water and last year the highest coverage was in September 6,011 ha. The maximum the KEMFRI has recorded in recent years is 16,000 ha while the minimum was less than 500 ha on Kenyan side. According to Dr. Chrispine Nyamweya, assistant director Limnology at KEMFRI, water hyacinth has reduced considerably in recent few years.
“We see a three year-cycle where it is at its maximum and then it goes to its minimum, said Dr. Chrispine Nyamweya, assistant director of Limnology at KEMFRI. “Over the recent month we have not seen much of water hyacinth especially around Kisumu area.” Scientists attribute the trend to the reduced nutrients concentration in the lake, following heavy rains in 2019, 2020 and 2021 that resulted into the dilution of the water.
Data from KEMFRI show that between July and December 2022 the highest coverage was 4,382.19 ha in August while the smallest coverage was 1,265 ha in December. “Our data has shown that water hyacinth in Nyanza gulf (Lake Victoria) nowadays don’t follow a cyclical pattern of emergence, growth, disappearance, and reappearance within a year as it was before.” Notes the factsheet from the research institute.
Slow use of mechanical approach to harvest the invasive weed
Scientists from KEMFRI noted in a factsheet that there seems to be a water hyacinth coverage reduction attributed to increased point-source pollution surveillance and stormy weather which might have increased water currents as the weed prefers almost still water for existence. Harvesters use is one of effective ways to deal with the notorious plant. However, previous efforts in that regard did not work properly and the harvester was underutilized. In 2021 Kenyan government through the ministry of environment unveiled a harvester that was said to harvest more than 15 tons per day.
However, the harvester did not work much according to environment activists. Mr. Nyaguti further said it was launched but never worked. “It has been rotting there in the lake. So, there is no history of doing anything in the lake, if there was then they will be showing us the documentation of its work.”
According to Mr. Nyaguti, the water hyacinth has never been managed mechanically successfully. In 2020 Kenya was on spot in the East African Community Legislative Assembly (EALA) over a $ 0.8 million idle weed machine. The $810,000 water hyacinth harvester bought in 2016 was underutilized, yet water hyacinth continues to affect aquatic life and environment, according to the EALA report at the time.
Additionally, biological methods were used in the past by introducing insects that would eat water hyacinth. Manual removal was also employed and is still being applied, although Nyaguti claims the trial programme was hindered by mismanagement and corruption as those who were qualified to do it were not involved. “There was a trial that was initiated by LVMII [Lake Victoria Management Project] and they contracted services providers, unfortunately some of them were not qualified,” he said.
Meanwhile, the Lake Victoria Basin Development Authority, a local institution is using a vessel to manage the weed. The vessel harvests and disposes the weed from the lake – especially on the sensitive beach areas that the weed interferes with the fishing activities and boat landing.
Fishery has been one of the most affected areas by the water weed. Paul Evans Didi, a former fisherman turned fishmonger started fishing in 2010 when he was accompanying his father. “I used to see water hyacinth covering all the nets we were using and it could carry the net from one place to another,” he said. “So that was a very big challenge.” According to Didi, when fishers’ nets were stuck in water hyacinth they could not access them again and had to apply for a loan to buy a new net. Sometimes fishermen were also stuck in the lake as boats could not move due to the invasive weed.
Now, communities in Kisumu hope the invasive weed will not come back. Since its recent decline some fishermen told The Standard, a local newspaper, that the lake is cleared and they have doubled their daily catch. According to scientists, water hyacinth and other organic materials also deprive the water of oxygen and making it inhabitable for fish and other aquatic life.
The use water hyacinth harvesting vessel also uses mechanical approach to removal of the water hyacinth. It only has advantage over other mechanical removal like physical removal by people getting to the shore lines by boats, explained Mr. Philip Oloo, director Agriculture and Natural Resources adding that “The capacity of the vessel is much higher and a lot more can be removed of a single operation.”
Limited collaboration
The water hyacinth is a transboundary problem of the five riparian Counties in Kenya: Busia, Siaya, Kisumu, Homa-Bay and Migori. This makes it difficult for its control since each county operates on resources and strategic plans within individual jurisdictions. The weed’s mobility is also free in Kenya, Uganda and Tanzania- Mr. Oloo further explained.
Lake Victoria Basin Commission coordinates collaboration efforts in East African Community, but Dr. Nyamweya stated that three countries come together to agree what should be done and the implementation is done at country level. The KEMFRI scientist also noted water hyacinth is relatively a big problem in Kenyan water. “In other countries It is not a big problem, because the water circulation to Uganda and Tanzania is better than Kenya.” Dr Nyamweya further explained.
In Tanzania, fishermen are said to manually remove it when they are in lake, a practice Dr. Nyamweya thinks can be successful in Kenya if it is well managed, saying it needs sensitization and motivation. In Kenya some are using excavators to remove the invasive floating plant in the lake.
Dr. Nyamweya further revealed currently there are efforts to develop a weed coverage prediction model so that they can inform resources users adequately.
*This story was supported by InfoNile with funding from JRS Biodiversity Foundation