Along the shores of Lake Victoria in Kochia, Homa Bay County, the water appears calm. Its surface is blanketed by thick mats of water hyacinth. To outsiders, the invasive weed symbolises environmental degradation.

But to the communities living along the shores of the lake, it represents something far more complex – a source of livelihood that is increasingly intertwined with growing health risks driven by climate change.

For generations, Lake Victoria has sustained thousands of families through fishing and related activities. Today, however, changing weather patterns, flooding and the rapid spread of water hyacinth are reshaping both livelihoods and public health.

“This lake helps us survive. Widows, orphans and even schoolchildren depend on it for subsistence,” Calvin Mingo, a resident of Kochia, says. “But the benefits have come with challenges.”

For some residents, water hyacinth is not simply an invasive plant. Beneath its dense cover thrives nyapos, small fish species that have become an important source of income.

“When there is water hyacinth, people are not jobless,” Peter Oyoma, who harvests nyapos from beneath the floating vegetation, says. “We sell it to fishermen and traders in Uganda, Busia, Usenge and even Tanzania. It has a ready market.”

The small fish are mainly used as bait for larger commercial species such as Nile perch and tilapia. Their trade provides seasonal income that helps families pay school fees, buy food and meet household expenses.

“When the water hyacinth drifts away, many people suffer,” Oyoma adds. “This thing gives people money.”

Yet earning that income comes at a cost. Harvesters spend long hours wading through stagnant lake water, often barefoot and without gloves or protection. Health experts warn that prolonged exposure has increased the risk of water-borne and neglected tropical diseases, with climate change worsening the situation.

“Most of our patients are fisherfolk who stay in the water for long periods,” Molly Ochar, a nurse and outreach coordinator working with beach communities, says. “That prolonged contact is why we see many neglected tropical diseases.”

According to Ochar, medical outreach programmes frequently diagnose bilharzia (schistosomiasis), intestinal worm infections, elephantiasis, river blindness and trachoma.

“These diseases thrive in contaminated or stagnant water,” she explains. “When sanitation is poor and flooding washes waste into the lake, the same water is used for drinking, cooking and washing.”

The health consequences are severe. Children suffer anaemia, malnutrition and delayed growth as parasitic worms deprive them of essential nutrients. Adults endure chronic pain, swollen limbs and declining physical strength, reducing their ability to earn a living.

“These conditions don’t kill immediately,” Ochar says. “But they slowly destroy productivity and dignity.”

Beyond physical illness, the uncertainty created by climate change is taking a psychological toll on fishing communities.

“The biggest challenge is not knowing what to do,” Everline Akoth says. “You wake up worried about food, school fees and sickness.”

Health workers say persistent illness, declining incomes and food insecurity are contributing to anxiety and depression, especially among fishermen who continue working despite deteriorating health.

“When the body is affected, the mind is affected too,” Ochar says. “We do counselling because many people feel ashamed or hopeless.”

The World Health Organization has warned that climate change is increasing the spread of water-borne and vector-borne diseases while also undermining mental health, particularly in communities whose livelihoods depend directly on natural ecosystems.

Water hyacinth is also disrupting fishing operations across Lake Victoria.

“When water hyacinth invades fishing areas, it destroys nets and blocks transport routes,” says Edward Oremo, Chair of the County Beach Management Unit. “Fish cannot reach the market. Prices fall. Accidents increase.”

He says some fishermen have become trapped in dense mats of hyacinth for days while navigating the lake, with some incidents proving fatal.

“Compared to the benefits, the dangers are many,” Oremo says. “The pace of dealing with this problem is still too slow.”

Climate scientists attribute the rapid spread of invasive aquatic plants to rising water temperatures and increased nutrient runoff associated with climate change.

In Kochia, local communities and health workers are adapting as best they can. Medical teams regularly conduct beach outreach programmes, provide mass deworming services and educate residents on sanitation, water treatment and disease prevention. Residents are also encouraged to wear protective clothing while working in the lake and to seek treatment early.

“We are focusing on prevention,” Ochar says. “Simple actions can reduce disease occurrence.”

However, residents argue that prevention alone cannot solve the widespread problem.

“We need jobs and support,” Erick Omollo, another nyapos harvester, says. “We are suffering.”

From Kochia to fishing communities across Africa, Asia and Latin America, climate change is transforming lakes, rivers and coastlines into frontlines of both economic survival and public health.

Standing on the shores of Lake Victoria, Mingo reflects on the contradiction that defines daily life for many families.

“This water is helping us so much,” he says. “But it is also challenging us.”

His words capture the delicate balance between livelihood and survival. As climate change continues to reshape ecosystems, the story of water hyacinth and nyapos demonstrates that environmental change extends beyond the natural world, directly affecting human health, incomes and wellbeing. For communities living closest to the lake, adapting to those changes has become an unavoidable part of everyday life.

• A Tell Media / KNA report / By Regina Joy and Davis Langat