Stubborn hyacinth chokes life out of Lake Naivasha fishing

In August 2016, two fishermen were trapped in Lake Naivasha after their boat failed to navigate through the water hyacinth.

The duo were on a fishing expedition when they got trapped. They sought help through mobile phones, and were rescued three days later.

Two journalists on an assignment suffered a similar fate in 2018 after their hired boat was arrested by the invasive plant. It took the rescue team more than eight hours to free them from the firm grasp of the weed.

And on the New Year’s eve, at least 20 boat operators were trapped in the fresh water lake for close to five hours before getting help.

These episodes highlight the danger fishermen plying their trade in the fresh water lake are exposed to as they eke out a living.

Boat operator Jeremiah Waraga said the insidious plant is also destroying their fishing nets.

“I lost nets worth more than Sh50,000 due to the presence of the weed in areas we had cast the fishing gears,” said the fishermen.

An aquatic biologist Mbogo Kamau blames the rampant presence of the weed to increased human activities that have led to the proliferation of nutrients that the invasive plant feeds on.

“The weed is anchored on floating papyrus mats,” he said, adding that the mats are a consequent of human activities that provide nutrients for them.

Mr Mbogo said hyacinth is a “notorious aquatic weed which greatly hinders navigation and access to fishing grounds within infested water bodies as is the case in Lake Naivasha.”

He said there are various ways — some of which have been applied at the Naivasha basin — of stemming the spread of the weed, but noted that so far these efforts have failed to achieve desired objectives.

“It can be controlled using host specific biological agents,” said Mr Mbogo.

However such a measure, he said, had failed at the lake due to the low population build-up of the biological agents to a level that could hamper the spread of the weed.

“Harvesting of the water hyacinth for economic use is an alternative and practical way of regulating the spread of the weed,” he said.

In 2011, Imarisha Naivasha, a government initiative, was launched with the aim of addressing the challenges facing the Lake Naivasha Basin, with removal of the hyacinth being a top priority.

The immediate objective of the programme was to conduct a pilot project of generating biogas using the weed. The project was being implemented by the Lake Naivasha Beach Management Unit (BMU) with financial support from Imarisha Naivasha Trust.

Despite the initial success of the plan, fishermen have been largely reluctant to manually harvest the weed, slowing down its anticipated benefits of the initiative.

Green energy

The project, according to Mr Mbogo, was intended not only to control the water hyacinth in the lake but also promote green energy production and utilisation among the local community as a strategy to reduce environmental degradation and cutting down of trees on the shorelines of the lake.

The Lake Naivasha basin attracts great attention both nationally and internationally due to its socio-economic and environmental significance. It is also a tourist destination site with the main attraction being the millions of flamingoes flocking the lake in their magnificent pink colour.

Aside from the assault by the hyacinth, the basin also faces multiple challenges arising from improper utilisation of natural resources and diverse stakeholder interests which sometimes conflict.

Key among this challenges include deforestation and loss of vegetation cover especially along the lake and river shores leading to alteration of hydrological flow regimes, increased siltation and sedimentation of the water bodies.

The water hyacinth found its way into Lake Naivasha in the late 1980s and has chewed up the entire shoreline of the water basin.

With the current level of the spread of the weed, the magnitude of the degradation of Lake Naivasha basin and the deterioration of economic base of communities living in Lake Naivasha basin, Imarisha Naivasha and conservationists face a daunting task in their efforts to return the area’s ecosystem to its lost glory.