Traffic jams on the snarled up roads of Nigeria's megacity of Lagos are legendary, but a growing problem is also clogging up the waterways of Africa's biggest city -- water hyacinths.
The spread of the invasive species of fast-growing plant is not only damaging transport links in Nigeria's economic capital, built on a lagoon dotted with islands.With waterways covered and silting up, the aquatic weed is also threatening fishing jobs and a vital food source.
"This is all I can get since morning," said fisherman Solomon Omoyajowo, showing a handful of fish in a bowl in his wooden canoe.
The 45-year-old fisherman has already been forced to move his nets from one part of the Ogun river too thick with weeds, to a new area nearer the sea.
"Many fishermen have abandoned their boats, while some of us who still want to continue, now try our luck here," he told AFP, using his palms to wipe a stream of sweat from his face.
"Water hyacinths are killing the fish in the river," said another nearby fisherman, Adisa, as he cast his net into the river.
When he hauled it up, he had caught only four small fish."I don't think I can do any other job apart from fishing," Adisa said. "I will continue to manage until the government comes to our aid to clear the weeds."
- Jobs at risk -
Originally from South America, the plant has caused chaos across several countries in Africa. Earlier this year, a thick green carpet of the weed choked up Kenya's main entry to Lake Victoria, the largest body of water in Africa.
It was first noted in Nigeria in the early 1980s, in the Badagry creeks west of Lagos, reportedly spreading from neighbouring Benin.
Since then, mats of weeds have spread to rivers across the country, including Nigeria's oil-rich Niger delta.
Fishermen say the weed is so thick it creates a dense cover that makes it difficult for fishing boats to navigate the river.
It is having a damaging impact.
One study, from Nigeria's Obafemi Awolowo University, estimated it put at risk one-third of Nigeria's local fish supply, a cheap source of food millions rely on.
That threatens to put thousands of fishermen out of a job.
"It has become a menace to the marine ecosystems of Lagos," said Nkechi Ajayi, spokeswoman from Lagos State Waterways Authority, adding that it impacted "the socio-economic activities" of river communities.
- Propeller problems -
Water transportation is also at risk. Operators complain of damaged boats and risk of accidents.
"We often find it difficult to navigate whenever the weeds clog the river," said boat driver John Ibikunle, as he waited to pick passengers on Lagos Island.
He said many commuters, who once preferred water transport to beat the perennial Lagos traffic gridlock, are returning to the roads, tired of being stuck on water with weeds snagging the propeller.
"They cause mechanical problems to the propulsion system of boats," added Ajayi, from the waterways authority.
The plant doesn't grow well in salt water, and environmental experts say the plant expands during the rainy season when the level of fresh water rises in Lagos lagoon.
"It is a seasonal plant," said Noah Shemede, an environmental activist, from the vast area of wooden homes on stilts built into the water, a fishing settlement called Makoko.
"In the Makoko community for instance, its impact is felt when the rain is heavy and the salt level is lower," Shemede said.
- 'Underwater lawn mower' -
Lagos State Waterways Authority chief Abisola Kamson said they have brought in two water hyacinth removal machines to clear the weeds.
"The machines act like an underwater lawn mower," Kamson said. "It cuts the vegetation, collecting and storing the weeds and debris on board."
But while fishermen and boat operators struggle with the weed, one local entrepreneur sees a business opportunity.
Achenyo Idachaba set up a firm that processes the weed into handwoven products including baskets and bags.
"The weeds are harvested from water channels and spread out in the sun to dry," Idachaba said. "They are processed into small ropes, required to weave the products together."
Some see a brighter future.
Scientists at the University of Lagos say the plant could also be converted into energy as biomass production, to help solve part of Nigeria's chronic electricity shortages.