A recent groundbreaking study has shed light on critical issues affecting fish health and antimicrobial resistance (AMR) in Lake Victoria, one of Africa’s most vital freshwater ecosystems.
As cage aquaculture expands rapidly to meet rising demand for fish, farmers are increasingly facing massive tilapia die-offs, threatening both their livelihoods and the sustainability of the region’s fishery resources.
The research, conducted by Cornell University in collaboration with the Kenya Marine Fisheries Research Institute (KMFRI) and the International Livestock Research Institute (ILRI), underscores the importance of adopting best management practices and robust biosecurity measures.
These strategies are essential to reducing fish disease outbreaks, enhancing farm profitability, and safeguarding the lake’s ecological health.
Between 2020 and 2023, fish farmers in the area reported over 80 large-scale mortality events, resulting in losses exceeding 1.8 million tilapia. Despite the scale of these incidents, only 39% were officially reported to public authorities, and a mere 17% of farmers attempted treatment—often without proper diagnosis or veterinary guidance.
To tackle these issues, Cornell, KMFRI, and ILRI organized workshops across western Kenya to promote improved biosecurity and management practices.
Key recommendations included the proper disposal of dead fish through burning or composting, strategic placement of cages in deeper, better-aerated waters, reducing clogged nets that hinder water flow, and prompt reporting of disease signs to authorities.
Lead author Eric Teplitz, a veterinarian and PhD candidate at Cornell, emphasized the complex nature of the problem. His team identified various bacterial pathogens linked to mortality events, often acting opportunistically due to environmental stressors like poor water quality.
“This highlights the need for a One Health approach that considers environmental health alongside disease management in aquatic systems,” he explained.
Significantly, this is the first study from Lake Victoria to isolate and identify bacterial pathogens involved in fish mortality and analyze their resistance to antibiotics. Several bacteria exhibited resistance to commonly used drugs, raising concerns about the rise of antimicrobial resistance in aquatic ecosystems.
CGIAR scientist Ekta Patel from ILRI pointed out that antimicrobial resistance is not just a human health issue but a broader threat to food systems. “Aquatic environments can serve as reservoirs for resistant bacteria and emerging pathogens. Strengthening surveillance is crucial for early detection and intervention,” she said.
The findings offer a pathway to align aquaculture practices with national and regional efforts to combat AMR and promote sustainable fisheries. They also underscore the importance of early disease monitoring, structured reporting, and evidence-based policymaking to improve fish health.
Christopher Aura, Director of Freshwater Systems Research at KMFRI, emphasized the need for better data sharing and coordination among farmers, regulators, and researchers. “This study demonstrates how locally grounded science can inform national biosecurity policies and antimicrobial stewardship strategies,” he noted.
Guided by Cornell’s Kathryn Fiorella, the research team advocates for an integrated approach to aquaculture regulation—focusing on responsible antimicrobial use, active farmer engagement, and enhanced diagnostic systems. Investments in fish health infrastructure are critical for ensuring food security and the long-term sustainability of East Africa’s burgeoning aquaculture industry.
As the sector continues to grow, these insights underscore the vital importance of safeguarding aquatic ecosystems and adopting scientifically informed practices to support a resilient, sustainable future for Lake Victoria’s fisheries.