Overview of More food and money, less disease: Senegal's surprising eco-experiment
NPR’s Short Wave explores an unusual but promising ecological experiment in Senegal: adding fish to rice fields to tackle three problems at once—schistosomiasis, low rice yields, and farmer poverty. Researchers are scaling up a trial across 60 fields to see whether fish can eat disease-spreading snails, fertilize the water, and provide an extra source of food and income for farmers.
The Core Problem
Rice farming, dams, and disease
- In Senegal’s Sahel region, rice farming expanded after dams were built in the 1980s to support dry-season agriculture.
- Those same dams unintentionally increased schistosomiasis (or “schisto”), a parasitic disease spread through freshwater snails.
- The dams created more snail habitat and blocked migratory prawns that previously ate snails and helped control the parasite.
Human impact
- Rice farmers are especially exposed because they spend long hours wading in water.
- The disease can cause serious symptoms like stomach pain, diarrhea, and fever, and in severe cases can contribute to long-term complications such as bladder cancer.
- Treatment exists, but access is limited in rural areas and reinfection is common.
The Experiment: Fish in Rice Fields
The idea
Researchers are stocking rice paddies with:
- African bony tongue (heterotis) — a large fish that eats lots of snails
- Tilapia — which mostly help by eating algae and competing with snails for food, while also producing fertilizer-like waste
Expected benefits
- Lower snail populations → reduced schistosomiasis risk
- More fish waste → natural fertilizer for rice
- Fish harvest → extra food or income for farmers
Why this approach is appealing
- Rice and fish are already culturally familiar in Senegal.
- The rice fields are relatively enclosed, so the risk of the fish becoming invasive is lower than in open natural ecosystems.
What Researchers Have Found So Far
Early results
- Earlier small-scale studies showed:
- About 25% higher rice yields
- Higher farmer income
- Slightly fewer snails
- Because sample sizes were small, researchers are now testing the approach more broadly across 60 rice fields.
On-the-ground example
- One farmer, Abu Diallo, said the fish transformed his farm:
- Rice sales increased from about 60 bags a year to 90
- He used the extra money to renovate his home and buy sheep
- He also eats or sells the fish from his fields
How the Project Works in Practice
Fish transport and stocking
- The NPR reporter joined the team as they transported nearly 2,000 tilapia from a fish farm to a rice farm.
- The more difficult fish—heterotis—are caught in the wild as juveniles and raised before being added to fields.
- Fish are gently released into the paddies using buckets and allowed to swim out on their own.
Data collection
Researchers are tracking:
- Snail density
- Rice growth, including drone-based measurements
- Farmer use of the fish
- Disease-related outcomes over time
Bigger Picture and Takeaways
Why this matters for Senegal
- Senegal still imports about half the rice it consumes, despite major rice production in the Senegal River Valley.
- If the experiment works, it could help:
- Reduce disease
- Improve food security
- Boost rural livelihoods
Main takeaway
This is a rare example of a biological solution to a biological problem that may also deliver economic benefits. If the larger trial confirms the early results, fish-based rice farming could become a scalable, Senegal-specific model for healthier and more productive agriculture.
Notable Insight
- The researchers see the project as especially promising because it aligns with local food culture: rice and fish are already central to Senegalese cuisine, especially in the national dish ceebu jën.
Bottom Line
Senegal’s experiment suggests that carefully designed ecological interventions can solve multiple problems at once. By reintroducing fish into rice paddies, researchers hope to cut schistosomiasis, improve rice harvests, and increase farmer income—all in one system.