Characterizing tilapia cage aquaculture biosecurity and production practices in Lake Victoria, Kenya

Fish kills Within the past 10 years, cage culture of Nile tilapia in Lake Victoria has transformed from a nascent, small-scale enterprise into an immense, commercial industry. Yet adequate information on production practices and the impact of fish kills is significantly lacking. To identify existing management practices, production constraints, and gaps in knowledge in Lake Victoria, Kenya, we conducted a cross-sectional survey using in-person questionnaires with 172 cage farm operations. Farms were selected using stratified proportional random sampling with additional snowball sampling. Descriptive statistical analysis indicated the major production constraints included: strikingly absent biosecurity practices, volatile input costs/availability, common incidence of large- scale fish kills, and harmful algal blooms. Fifty nine percent of farmers reported disposing dead fish into the lake, feeding to other animals, or consuming them. Only 23% of farmers reported disease to aquaculture in stitutions, only 2% disinfected tools used across cages, and none reported access to appropriate antimicrobial therapeutics. Forty percent of farmers experienced a large-scale fish kill within the last year. Algal blooms, present on 81% of surveyed farms, were reported to reduce fish growth/survival, clog cage nets, and trigger fish kills. Farmers are rapidly adopting commercial feeds, yet feed prices and availability remain volatile. The vast majority of farmers (90%) do not produce their own fingerlings, underscoring a critical dependency on private and government-run hatcheries that have not been well-characterized. In identifying gaps in management practices and production constraints, this study provides more specific targets for subsequent extension to improve biosecurity, fish health management, profitability, and environmental sustainability