Scientists have raised an alarm over the rising pollution levels in Lake Victoria, which are contributing to recurring fish deaths across the lake. In findings published by the Kenya Marine and Fisheries Research Institute, the presence of oil layers in parts of the lake and high concentrations of ammonium and nitrite have shown evidence of the discharge of toxic effluent into the freshwater body. As Laura Otieno reports, the findings have renewed calls for stricter enforcement of existing environmental protection frameworks.
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...nats.... (Lake shots) The calm waters of Lake Victoria.... (Fishermen reeling in nets or boats to the shore) Has been a source of livelihood for thousands across East Africa over the years. But a wave of death swept in between 2023 and 2025 as cage fish farmers operating in Lake Victoria recorded losses running into an estimated 3 billion shillings…..

a crisis of the massive fish deaths that swept across the lake, leaving a trail of loss as farmers from Kisumu and Busia counties were the hardest hit….Initial investigations linked the deaths to upwelling - a natural process where deep water with low dissolved oxygen rises to the surface, suffocating fish. The phenomenon forcing farmers to be extra vigilant with aquaculture processes

UPS (VICTOR DIDI – CAGE FISH FARMER, DUNGA BEACH): WHAT WE CAN DO BETTER AND WE EVEN DID AROUND OCTOBER WHEN WE HAD FSH KILLS IS PLACING OUR CAGES IN THE RIGHT SPOT WE USED TO HAVE OUR CAGES CLOSE TO THE SHORE AND THAT WAS A CHALLENGE THAT US AS FARMERS WE BROUGHT TO OURSELVES BUT WHERE WE ARE IS A VERY GOOD SPOT RECOMMENDED BY GOVERNMENT

New findings now show that pollution also played a role, causing the death of fish even outside the cages. The Kenya Aquatica Journal published by KMFRI showing that water samples collected between November 2024 and January 2025 had elevated levels of phosphorus and nitrogen. Researchers say the pollutants that were collected from three points including River Kisat mouth likely came from surface runoff, sediment disturbance, untreated sewage and industrial discharge. A running problem exacerbated by the lake’s proximity to major urban centers.

UPS (DR. CHRISTOPHER AURA - DIRECTOR OF FRESH WATERS
SYSTEMS, KMFRI): THE ENTIRETY OF KISUMU IS CONTRIBUTING ABOUT 7,000 TONS PER YEAR OF PHOSPHATES. FOLLOWED BY SIAYA. SIAYA WOULD BE BECAUSE OF INCREASED DISCHARGE FROM RIVERS THAT WE HAVE MAJOR RIVERS FROM THAT SIDE ON THE ON THE SIAYA SIDE. AND MAYBE WE ARE TALKING ABOUT INDUSTRIAL TOWNS LIKE KAKAMEGA LIKE WEBUYE THAT ARE HAVING SOME OF THESE MAJOR FACTORIES.

For lakeside communities, the impact of effluent flowing in to their source of livelihood is visible and worrying.

UPS (MICHAEL NYAGUTI - RESIDENT, KISUMU): WE HAVE HAD
INSTANCES WHERE COMMUNITIES ARE REPORTING THAT AT ONE
POINT THE WATER WAS TURNING IN TO SOMETHING DARKISH, I WANT TO URGE THE PEOPLE TO PLEASE HELP US SO THAT WE ARE ABLE TO REPORT ANY COLORATION THAT IS NOT NORMAL THAT WILL help US AS ENVIRONMENTALISTS TO FOLLOW UP ON THE REAL CAUSE OF THIS THING THAT IS EXPOSING CAGE FISH FARMERS TO ECONOMIC SABOTAGE

Lake Victoria is a transboundary resource shared by Kenya, Uganda and Tanzania, and is protected by national laws as well as regional agreements. Kenya imposes fines of up to four million shillings for discharging toxic waste into water bodies. Uganda on the other hand fines offenders up to 1.6 million dollars for large-scale hazardous discharges, while Tanzania sets a minimum penalty of 7,200 dollars. Environmental groups are now pushing for coordinated cross-border enforcement as well as community sensitization in order to curb pollution.
UPS (PAMELA STEELE - PUBLIC HEALTH CONSULTANT): WASTE DOES
NOT CREATE ITSELF AND IT IS NOT JUST CONFINED IN CITIES ORA.
COUNTY SET UP SO WE NEED TO HAVE CONVERSATIONS ON
LOCALISATION WE NEED TO THINK ABOUT HOW TO GET THESE
SESSIONS EVEN TO LOCAL CHIEFS AND EVEN THE YOUTH

Kenya’s penalties stem from the Environmental Management and Coordination Act, developed after the country signed the Bamako Convention in 1991.The convention aims to protect Africa from hazardous waste. Kenya deposited its instruments of ratification in 2025. Researchers say the latest findings strengthen the case for stricter enforcement of the Bamako protocol.
UPS (OMONDI KASIDHI – PLATFORM DEVELOPER, YARA INTERNATIONAL): I THINK THERE IS AN INTERNAL PART OF THIS THIS CONVENTION THAT IS REALLY IMPORTANT. IT TALKS ABOUT THE MANAGEMENT OF WASTE AND NOT SPILLING WASTE ON INLAND WATERWAYS. BECAUSE YOU SPILL WASTE INTO LAKE VICTORIA IN KISUMU, IT WILL END UP IN ENTEBBE. IT WILL END UP IN MWANZA. IT WILL IMPACT ALL THOSE STATE PARTIES THAT MAYBE DONT EVEN KNOW THAT YOU’RE SPEWING THIS CHEMICAL INTO LAKE VICTORIA

With research now linking pollution to economic losses and long-term environmental damage, scientists and activists are urging greater public vigilance. For now, protecting Lake Victoria is not only about enforcement but also about safeguarding livelihoods and preserving one of Africa’s most important natural resources.

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