By Treezer Michelle Atieno
A collaborative effort involving the County Directorate of Fisheries and Blue Economy and the Kenya Marine and Fisheries Research Institute (KMFRI) investigated the causes of pollution in Lake Victoria affecting fish farmers.
Between November 2022 and February 2023, fishermen reported significant fish die-offs at beaches on Lake Victoria, including Ogal and Asat in Seme Sub County.The Ogal Beach Management Unit expressed concern about untreated industrial waste being directly discharged into the lake, resulting in losses amounting to hundreds of millions of Kenyan shillings.
Dr Christopher Aura, the Director of Fresh Water Systems Research at KMFRI, identified a natural occurrence called upwelling as a significant factor. Upwelling, influenced by changes in wind direction, causes colder, deeper waters to rise and replace the warmer surface waters, leading to a lack of oxygen. This oxygen deficiency has been linked to significant fish deaths, particularly affecting caged fish.
Dr Aura explained that major upwellings usually occur from February to March and September to early November, and unpredictable upwellings can happen at any time. Farmers are advised to monitor changes in water colouration and consider harvesting mature fish early to reduce losses. Additionally, KMFRI is available for consultations on optimal cage placement to minimize risks.
NEMA Officer Leonard Ofula emphasized the need for concrete evidence to support claims of industrial effluent discharge. He highlighted the importance of proactive conservation efforts upstream, as pollutants like nitrates and phosphorus from the highlands contribute to lake contamination. Taking action upstream is crucial to mitigate pollution downstream in the rivers that flow into the lake.
The stakeholders reached a consensus on a comprehensive approach to addressing pollution. One important resolution was to call on the Kisumu Water and Sewerage Company (KIWASCO) to upgrade its waste treatment systems. Currently, these systems operate at only 23% capacity despite the growing population of Kisumu. It is also crucial to monitor and regulate private exhausters who illegally dump waste into the lake.
Hon. Kenneth Onyango, CECM for Fisheries and Blue Economy, emphasized the need for coordinated efforts among agencies to prevent conflicts in a jurisdiction and ensure effective pollution control. He called for continuous engagement with stakeholders to protect Lake Victoria’s aquatic life and the livelihoods of fish farmers.
Lake Victoria, the largest lake in Africa, supplies water to over 40 million people in Kenya, Tanzania, and Uganda. Unfortunately, the lake has become polluted, threatening aquatic life and human populations.
Pollution sources in Lake Victoria include agricultural runoff, industrial waste, and untreated sewage. Fertilizers and pesticides from nearby areas flow into the lake during rainfall. Factories along the lake’s shores release untreated wastewater into the lake.
The effects of pollution on aquatic life are concerning. Studies show that fish populations are declining due to habitat destruction and contamination. The Nile Perch, an economically important species, has been affected by pollutants, experiencing a decrease in size and weight. Additionally, invasive water hyacinths have thrived due to nutrient enrichment from agricultural runoff, causing oxygen depletion and fish deaths.
Human populations around Lake Victoria are also suffering from pollution. Contaminated water sources have led to the spread of waterborne diseases like cholera and typhoid fever. Fishing communities have reported lower catches and increased health risks from consuming contaminated fish. This has resulted in food insecurity and economic instability.
Governments and international organizations are tackling pollution in Lake Victoria. The Lake Victoria Basin Commission has developed a Strategic Action Programme on the Environment (SAP-E) to reduce pollution by improving wastewater management and promoting sustainable agriculture practices. Non-governmental organizations are also working on projects to restore degraded habitats through reforestation and community-based conservation initiatives.