Farmers in northern Senegal are turning rice paddies into combined crop-and-fish production systems, using fish to control pests, enrich soils, and create an additional source of food and income while potentially reducing the risk of schistosomiasis, a parasitic disease associated with freshwater snails.
The approach is being tested in communities in the Senegal River Valley, where more than 40 farmers are participating in a research project that integrates fish farming directly into rice fields. The pilot has attracted attention because it combines agricultural production with an ecological approach to disease control and rural income generation.
Research published in Nature Sustainability found that integrating native Nile tilapia and African bonytongue into rice fields increased rice yields by more than 25 percent. The fish also suppressed insects and freshwater snails, while their waste added nutrients to the soil, reducing the need for some external inputs.
The system addresses a particular health challenge in northern Senegal. Rice farmers spend significant periods working in irrigated fields and can be exposed to freshwater snails that host the parasites responsible for schistosomiasis. By introducing fish that prey on the snails, researchers are testing whether the farming system itself can help interrupt part of the disease's transmission cycle.
The economic case is also significant. The study estimated a net benefit of between $1,805 and $3,415 per hectare per year, with a benefit-to-cost ratio of 7.42. Farmers can harvest the fish for household consumption or sell them, creating another revenue stream from land already being used to grow rice.
For farmers participating in the trials, the changes are visible in the fields. Fields containing fish appeared greener than fields without them, attributing the difference partly to fish waste acting as a biological fertiliser. He said income from the first harvest also enabled him to invest in sheep and poultry.
The model builds on knowledge that has existed in parts of Senegal for generations. Traditional rice-fish farming has long been documented in areas such as Lower Casamance, where rice cultivation and fish production have historically been integrated as complementary livelihood activities. New research is now testing how that principle can be adapted and strengthened using modern ecological and agricultural science.
Researchers are continuing to measure fish survival and growth, rice yields, water quality, insect populations and snail abundance. The longer-term ambition is to determine whether the approach can be scaled beyond the pilot and adapted to other rice-growing regions where aquaculture and irrigated agriculture coexist.
NBF Insight
Senegal’s rice-fish model demonstrates how one farming system can potentially solve several problems at once.
Instead of treating rice production, aquaculture, pest control, soil fertility, and rural incomes as separate challenges, the system connects them. Fish provide food and additional income, their waste contributes nutrients, and their predation can reduce populations of organisms that damage crops or contribute to disease transmission.
The significance goes beyond Senegal. Africa is under growing pressure to produce more food without continuously expanding cultivated land or increasing dependence on costly external inputs.
Rice-fish farming offers one possible pathway: produce more from the same piece of land by making different parts of the farm ecosystem work together.
For smallholder farmers, that could mean not simply harvesting more rice, but creating a farming system that produces grain, fish, nutrients and income from the same water and land.
