Aquaculture extension systems in East Africa: development, challenges, and future opportunities

Aquaculture extension enables the shift from subsistence to competitive production in East Africa. Yet, coverage and quality remain uneven, limiting technology adoption, farm productivity, and knowledge transfer among small-scale producers. We assessed the development and performance of aquaculture extension in Uganda, Kenya, and Tanzania, and identified design features that accelerate impact using Egypt as a benchmark. We conducted a systematic literature review with structured searches of major databases and grey literature from 1990 to March 2025, with Explicit Inclusion Criteria and the Mixed Methods Appraisal Tool. Findings show pluralistic yet weakly coordinated ecosystems. Public services protect equity, biosecurity, and standards, but face chronic underfunding and farmer-to-agent ratios often above one to one thousand. Donor and NGO programs spread farmer field schools and demonstration ponds, yet gains often fade after projects end. Private embedded and fee-based advisory delivers timely and site-specific support in commercial clusters but raises conflict of interest risks and limits access for poorer or remote farmers. Compared with Egypt, where sustained state coordination, production zones, and strong research-to-extension links prevail, East African trajectories are fragmented and cyclical. Across channels, blended digital and human delivery achieves stronger adoption than digital only. Evidence on costs, sustained adoption, inclusion of women and youth, and environmental outcomes remains thin. Heterogeneity and short follow-up limit inference. The review outlines a practical agenda that protects public goods, accredits and co-finances private advice, strengthens research to extension to farmer platforms, invests in competency-based training and inclusive multilingual digital human blends, and adopts shared metrics for cost and impact.