Fishermen ignore toxic fish, wade into flooded Lake Nakuru for thriving livelihoods

They contain nitrites, heavy metals and other toxic substances from pollution caused by agricultural runoff, industrial discharge and untreated human waste. The lake has no outlet so dangerous elements accumulate.

The fish rot faster than fish from other lakes and some people complain of a foul taste; others say the fish tastes okay, or good.

Business is booming.

Despite warnings, fishermen and unemployed youth still go fishing for tilapia and mud fish, consume them or sell them to the public.

Research by the Kenya Marine and Fisheries Research Institute (Kemfrei) showed fish tissue samples contained high levels of nitrites and traces of other hazardous chemicals.

The Nakuru county Health department and the Kenya Wildlife Service have been manning the fishing points to keep away commercial and subsistence fishermen.

Much of the illegal activity, however, continues outside the game reserve and on private farms where the lake had flood and waters spilled over. Many are foot fishermen, wading in with nets.

Lake Nakuru has three newly introduced tilapia fish species that previously never existed there, according to a recent study.

Until the recent rise in lake water levels, researchers say there was only one species, Tilapia Grahami, which was introduced in 1953 in the soda lake. The new fish species have attracted residents and makeshift eateries have sprung up on the lake shores.

For many years, the lake was also inhabited by cichlid, a small type of fish that can tolerate harsh conditions. It was introduced in the early 1960s and has flourished.

Fishing within the farms flooded by lake water gives residents a rare opportunity to fish and supply the eateries in towns.

At the famous Ponda-mali market traders are up by 5am waiting anxiously for the precious product from various fishing points which is ferried on motor bikes and pick-ups.

A spot check by the KNA showed the ban seems to be ignored as traders carrying the fish packed in boxes and sacks arrive at Soko Mjinga, Ponda-Mali, Free Area and Ronda markets. Women with basins scramble for the catch.

Business is booming, the returns are good…we lost our farms to floods but our relief comes from the handsome returns from our fishing 

Phanice Ayuma sells lake tilapia  popularly known as ‘blackie’ at Soko Mjinga market in the sprawling  Kaptembwa settlements.

She said she knows about the ban but her business has not been affected this year.

“Cash availability is a problem at this time of the year and we need to sell ‘ngege’ from Lake Nakuru to provide for our families. We have not been stopped officially from getting this type of fish,”Ayuma. said

She sells tilapia at Sh50 to Sh200, depending on the size. Prices rise when the fish is scarce.

Near many private homes in Mwariki village that have been almost submerged, fishermen continue casting their nets wide, undeterred by the ban.

Henry Kamotho is among more than 60 residents whose fields were submerged and he now is cashing in on the fishing industry that is largely unregulated.

"Business is booming and the returns are good…we lost our farms to floods but our relief comes from the handsome returns from our fishing activities,” he said.

Kamotho said most of his former neighbours have taken to fishing in their former farms as the trade was more lucrative due to lack of stringent regulations and membership terms.

Fish trader Alex Maranga said, however, he stopped selling fish from Lake Nakuru early last year, because they decayed very fast, leading to huge losses.

“My customers started complaining that fish from Lake Nakuru had a foul taste. I cannot trade in that fish. I always ask where the fish I am about to buy is from.

"Those who sell different species from the lake have also incurred losses due to their fast rotting,” Maranga who operates at

Free Area market said.

In Nakuru Town West's Ronda market, fishmongers appealed to the government to allow fishing in Lake Nakuru since it cushions them from hunger.

Florence Akinyi said the ban is punitive to those who previously relied on businesses around the lake for their livelihood. 

“Now that the water has displaced us, we have to fish and sell to survive. We are fishing within our own farms and the fish tastes good,” Jane Njambi, one of the Mwariki residents said.

A number of Fishmongers and hoteliers interviewed at the Nakuru Central Business District maintained that even before the ban, they used to get fish from other sources.

“This establishment has never traded in fish from Lake Nakuru. We source our fish from as far as Lake Victoria and Turkwel. There are also a number of private aquaculturists who supply us,” Janet Kahiko, a proprietor of an eatery on Kenyatta Avenue in Nakuru, said.

The booming business within Mwariki has further attracted fishermen from Lakes Naivasha and Victoria to explore new possibilities.

“I relocated from Naivasha to help assist owners of these farms maximize on their profits. We split profits from the fish I get from their farms,” fisherman Kelvin Njoroge said.

Fisherman James Otieno moved from Lake Victoria and he said the fish size "is not bad" and farmers are getting good revenue.

“It is just the ordinary fish, except that we are not allowed to move deeper past the face separating residential areas and the park,” Otieno said.

Seasoned fishmonger at Ponda-Mali market Derrick Ouma called Nakuru fish foul-tasking compared to fish caught in lakes Naivasha, Turkana and Victoria.

"I have never eaten the fish because of my concerns about safety but others say it is not palatable," he said.

Ouma said fish from Lake Nakuru have found their way to markets in Nairobi, Kiambu, Kericho and elsewhere but he said his aversion remains strong.

Kemfri researchers began investigations after constant complaints by fishmongers, especially after some fish were found dead in the lake in January 2020. Researchers found high levels of nitrites, raising safety concerns.

Experts reported the mysterious deaths were caused by the toxicity of the four fish species in the lake. Nile tilapia were the worst affected by the deaths. Most of the dead fish were larger than average.

Besides nitrate, the concentration of chlorophyll-a in the fish was found to be 84.49 milligrams/litre (mgl-1) while others had a concentration of 77.35 mgl-1.

Some of the points within Lake Nakuru were found to have the nitrates at a concentration of 67 milligrams per litre indicative of organic and inorganic discharge into the lake. This discharge could originate from industrial or municipal waste.

The concentration of chlorophyll-a, the report notes, is indicative of the excessive nutrient loads in the water and led to an increase in algae biomass.

The scientists note that nitrates are toxic in amounts greater than 45 milligrams/litre, and that the environmental conditions in Lake Nakuru are not optimal for the growth and reproduction of the fish.

The World Health Organization says the recommended level of nitrate is less than 45 milligrams/litre. Anything above that is considered not fit for aquatic life.

Toxic heavy metals were detected in all fish samples. 

“The levels of chromium exceed the FAO limit of 0.14mg/l and other toxic metals are of concern,” researchers said.

Heavy metals in the fish, in small concentrations, researchers say, may not pose an immediate health threat to consumers of fish and fish products from Lake Nakuru.

But long-term consumption has adverse effects on the nervous system since heavy metals will accumulate in the body.

The researchers further blame pollution of Lake Nakuru, saying more than 65 percent of untreated human waste ends up in the lake, due to inefficient transport and treatment. Solid waste, stormwater and drainage management are also limited.

“This is the reason that the lake is completely anoxic (without oxygen) and cannot support life, particularly in the mid-lake and at depths below one metre from the surface,” the report on research read.

The cocktail of heavy metals include cadmium, chromium, lead, nickel, mercury, selenium, cobalt, copper and zinc were reported as the most frequently occurring heavy metals. Molybdenum exceeds recommended standards.

“Chromium, copper, lead and zinc have accumulated in the sediments as a result of unregulated discharge lnd because this alkaline lake has no outlet,” researchers said.

(Edited by V. Graham)

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