Turning challenges into opportunities: affordable aquaculture systems in Kenya

In Nyeri County, Kenya, a team of Dutch and Kenyan partners is testing a water technology innovation that could transform local fish farming. Supported by Partners for Water, the Affordable Recirculating Aquaculture System pilot project (A-RAS-2) is led by the Food Systems and Poverty Alleviation (FOSPA) Foundation in Africa, in collaboration with FOSPA-Kenya and Systemic Consultancy. The project addresses Kenya’s severe protein deficit and the recurring challenges of drought. Project leads Katrine Soma and Charles Mbauni share how it works.

A systems approach

At its core, A-RAS-2 offers small-scale fish farmers a water-efficient, nutrient-reusing, solar-powered alternative to traditional ponds. The pilot project aims to demonstrate that these systems can produce up to 25 times more fish while using only 2–5 percent of the water required in conventional ponds and providing manure for the farmer’s mixed farming systems.

But A-RAS- 2 is more than just a new water technology, it adopts a systems approach built on a deep understanding of the local food system and its interlinked challenges. Beyond addressing farmer’s needs, the project strengthens multiple links in the chain. It stimulates local entrepreneurship in producing technology components and fish marketing and improves consumers access to affordable, nutritious food. On a wider scale, it contributes to climate-neutral, resource-efficient food production with the potential to save over 216 million cubic metres of water per year across Kenya.

From research to practice

For nearly a decade, social scientist Katrine Soma has studied Kenya’s food systems with a particular focus on fish. She works at Wageningen Social and Economic Research and is the chair and founder of the FOSPA-Africa Foundation in the Netherlands. Working closely alongside her is Charles Mbauni, chairman of the Nyeri Fish Farmers Cooperative Society and co-founder and chair of FOSPA-Kenya.

“I have worked in Kenya since 2018, researching bottlenecks in the fish food system,” explains Soma. “Through FOSPA-Africa, Charles and I combine research and implementation hand in hand.”

Mbauni adds: “As chairman of the cooperative, I saw first-hand the challenges in water use, fish growth and costly technology. That is how the idea of an affordable recirculating aquaculture system was born.”

Transforming challenges into innovations

“Kenya, like much of the Horn of Africa, faces chronic food insecurity, mostly driven by climate change and recurring droughts,” says Mbauni. “Protein is in particularly short supply. When drought strikes, traditional sources such as beef and sheep are no longer sustainable due to their high water footprint.”

Recognizing this, the government launched the ‘Eat More Fish’ campaign to promote fish consumption,” explains Soma. Mbauni adds: “Demand for fish is high and far exceeds local production. In fact, 70 per cent of fish consumed in Kenya is imported.”

Against this backdrop, A-RAS offers a breakthrough. “Traditional ponds are about 300m2 and stock no more than five fish per cubic metre, producing around 280 kilograms per pond,” notes Mbauni. “By contrast, A-RAS can reach densities of nearly 200 fish per cubic metre, producing more than 7,000 kilograms in the same space.”

“This is an enormous difference,” says Soma. “It means more fish, more protein, and at the same time we release land and water for other purposes”.

Practical, affordable and circular water technology

The technology is both innovative and pragmatic. “Recirculating aquaculture systems are usually expensive,” says Soma. “We focused on affordability – using local materials, cheaper or second-hand parts and high quality components where essential.” The result is a mix of simple tanks and advanced yet affordable water management.

“The tanks are made locally and in a simple yet durable manner,” explains Mbauni. “At the same time, the air and water pumps are high quality and supplied by Dutch entrepreneurs.” A settling tank filters solid waste, which is reused as fertiliser. A nitrification tank with microorganism removes nitrogen. Different oxygenation technologies are being tested, including nano and microbubbles.

Mbauni continuous: “Each system has six tanks with fish at different growth stages, allowing farmers to maintain a steady income throughout the year. This enables them to reinvest in quality feed essential for water and fish health.”

Soma concludes: “In the end, it is high-tech translated into practical, affordable solutions. And because the system runs on solar energy for water recirculation, it is climate neutral,”

Consortium and partners

The pilot project builds on a feasibility study carried out by FOSPA-Africa together with AquaFarmingConsult and Wageningen University & Research, supported by Partners for Water.

In this second phase, the consortium consists of FOSPA-Africa, FOSPA-Kenya and Systemic Consultancy. FOSPA-Africa brings together research, implementation and technical and financial expertise to refine the water technology and develop accessible business models for scaling.

Engaging stakeholders

From the start, farmers have been at the heart of the project. Mbauni represents a cooperative of around 1,000 fish farmers whose feedback informs every stage of the process. To ensure diversity, five farmers were involved in both the feasibility study and the pilot, among them women, young farmers and a disabled farmer.

“Working with the cooperative means we know immediately what works and what doesn’t,” says Soma. “Farmers tell us: this is a good idea, that is not. This direct communication saves time and ensures solutions are truly practical and acceptable.”

This bottom-up approach goes beyond farmers. In Kibera, Nairobi’s largest informal settlement, local leaders, consumers and women vendors co-created solutions for fish distribution. “Our solution is not an external, foreign thing,” says Mbauni. “It’s embedded in the community, where people trust and support each other.”

Next steps

To advance the project, the consortium has built a new A-RAS-2 facility in Nyeri County. “This enables gathering of reliable data and refining oxygenation technologies, with the first results expected next year,” says Soma.

On this basis, the project aims to scale up across Kenya, moving from fish production to a complete food system with feed, fingerlings, processing and training hubs. “We’re developing financing models to make the systems accessible for small-scale farmers,” notes Mbauni. “The long-term goal is to turn proven pilots into a nationwide movement, with potential expansion to neighbouring countries such as Uganda and Ethiopia.”

Innovation in progress series

The Partners for Water 5 programme (2022 – 2027) follows several projects that received the Partners for Water subsidy from start to finish. Over the next few years, these projects will take you on their journey of testing the feasibility or application of innovative solutions to enhance water safety and water security abroad. You’ll be able to gain insights into their processes, collaborations with local partners and their potential solutions; as well as their struggles, challenges and their lessons learned. Discover all projects.