Introduction

Fishing is an important economic activity for several communities living across the shores of Lake Victoria. It is estimated that about three million people from Tanzania, Kenya and Uganda are employed in the Lake Victoria fish value chain. Within Tanzania, which hosts half of Lake Victoria, the small-scale fishing industry is a primary source of income for more than 300,000 people, the majority being women and youth. Other than Nile tilapia (Oreochromis niloticus), small fish (sardines) locally known as dagaa (Rastrineobola argentea) have been one of the most popular commercial fish products and widely consumed across East Africa. Over 300,000 tonnes of dagaa are consumed annually in Tanzania, a third of which are for human consumption, and 70% are used as animal feed.

The popularity of dagaa among East African consumers is attributed to several nutritional and health benefits, including being a major source of protein and omega-3 when consumed as dried fish. In the last few years, the production of dagaa has increased from 289,873 tonnes in 2010 to 433,845 tonnes in 2015, generating over $2 million due to the rising demand for dagaa in the Democratic Republic of the Congo and other neighboring countries. Despite this massive economic potential, small-scale fish processors, distributors and traders face many postharvest challenges in handling harvested dagaa, making the industry unprofitable. Many lack proper postharvest processing facilities and, hence, rely on traditional fish processing practices like open sun drying, where harvested dagaa is left on the bare ground in the sunshine for hours. However, this kind of processing practice exposes dagaa to sand, rocks and external contaminants, which pose serious health risks (foodborne diseases) to consumers.

Postharvest fish processing practices like smoking and open sun drying are also unhygienic, unreliable and inefficient, leading to up to 40% postharvest fish losses. And when the rainy season starts, losses become even higher because there is a lack of sunshine, and harvested dagaa must be processed (dried) indoors.

Turning to solar dryers

Since most fishing communities in Lake Victoria are located in off-grid areas that are not connected to the national grid, modern food processing infrastructures are costly and difficult to introduce to these communities. Fortunately,  in most parts of East Africa, the sun is abundant and readily available throughout the year, making regions close to Lake Victoria ideal sites to promote and deploy solar dryers. One major advantage of solar drying technology is that solar dryers are simple and easy to fabricate because the raw materials (including solar panels and others) can be sourced locally, which makes them inexpensive to maintain over the long term. As such, adopting simple and affordable solar dryers that can be locally made would benefit small-scale fish processors in Lake Victoria, helping them avoid spoilage and deliver clean and safe dagaa to consumers.

But, in Tanzania and elsewhere in East Africa, the technology is underdeveloped and unknown to potential beneficiaries, especially fish processors in Lake Victoria. My interactions with small-scale fish processors, government officials and policymakers in the Lake Victoria fish value chain indicate that there have been limited efforts to promote and disseminate this technology. This lack of investment, combined with the low technical capacity to fabricate and deliver these facilities, has resulted in poor access to solar dryers for fish communities in Lake Victoria.

To resolve this problem, since 2022, MAVUNOLAB, in collaboration with the Karume Institute of Science and Technology (KIST) and the government of Tanzania fisheries agencies, including the Fisheries Education and Training Agency (FETA), has begun promoting and pushing for the adoption of solar dryers among small-scale fish processors in two fish communities in Lake Victoria: Kayenze Ndogo and Mswahili, Mwanza region, Western Tanzania. The solar-powered dryer developed by MAVUNOLAB is a low-cost solar drying facility designed to provide quality preservation and processing of up to 500 kilograms of dagaa in less time. It has multiple drying racks covered with glass and a solar panel placed on top to absorb and retain maximum solar radiation (energy), reducing moisture, food spoilage and postharvest fish losses.

Our recent pilot test results reveal that MAVUNOLAB’s solar dryers can process (dry) up to 200 kilograms of dagaa in less than six hours. This is less time compared to the 12 hours it takes when small-scale fish processors use smoking or open sun drying. The reduction of drying time also significantly reduces fish spoilage that often occurs when processing food with traditional practices. More importantly, when using solar dryers, food products such as dagaa are processed in a clean and safe environment because they are protected from dust, flies, fungal attacks or potential damage from birds and other animals. The availability of this technology will be crucial to the livelihoods of women who dominate the Lake Victoria fish processing value chain. In addition to avoiding losses and spoilage, they will earn more and deliver clean and high-quality dagaa that can meet international export requirements.

Scaling-up access to solar dryers: what needs to be done

Strengthening access to postharvest technologies such as solar dryers has several benefits to local food systems. It will boost supplies and export earnings of dagaa, which will improve the living conditions of thousands of women and youth employed in the Lake Victoria fish value chain. In Tanzania, investment in affordable postharvest technologies that can help small-scale farmers, food processors, fishers and traders avoid food losses has been emphasized in most policy documents, including the National Postharvest Management Strategy and the African Union Malabo Declaration. However, at the moment, more needs to be done to increase awareness and local capacity to fabricate and disseminate solar dryers. This can be addressed by closing the technology development gap through training more local technicians in fish communities where solar dryers are lacking.

Over the past few months, MAVUNOLAB has trained 10 young graduate engineers in solar drying technology with the goal of building more local skills and addressing the knowledge gap, particularly in the Lake Victoria region, with plans to expand to Lake Tanganyika and other places with similar postharvest challenges. As more people are skilled enough to fabricate these dryers locally, this will eventually improve access and eliminate unnecessary losses, not just of dagaa, but of other perishable food commodities that can be dried when unsold due to postharvest storage challenges in Tanzania.