More food and money, less disease: Senegal's surprising eco-experiment

Summary

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Episode Overview

Title: More food and money, less disease: Senegal's surprising eco-experiment
Date: August 4, 2026
Hosts: Regina Barber (NPR), Jonathan Lambert (NPR Global Health Reporter)

This episode of Short Wave explores a bold eco-experiment in Senegal where researchers are addressing three critical issues with a single inventive solution: fighting a debilitating disease (schistosomiasis), improving rice production, and reducing poverty among rice farmers—all by introducing specific fish species into rice fields. The episode blends on-the-ground reporting, scientific context, and cultural insight to unpack the strategy and its real-world impacts.

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Key Discussion Points & Insights

1. The Three Problems Facing Senegal's Rice Farmers

• Debilitating Disease
  • Schistosomiasis, caused by a parasitic worm hosted by freshwater snails, is rampant among rice farmers due to constant exposure to water.
    • “It's basically like your standard snail, but they can be pretty tiny, but they're still really dangerous.” – Jonathan Lambert [04:19]
    • Infection leads to complications like stomach pain and, in severe cases, bladder cancer.
• Boosting Rice Production
  • Despite increased rice farming near the Senegal River, the country still imports about half the rice it consumes.
• Fighting Poverty
  • Low rice yields and recurring health issues keep farmers in poverty.

2. Origins of the Problem: The Dams and Their Unintended Consequence

• In the 1980s, dams built to facilitate irrigation enabled rice farming but also disrupted the natural environment.
  • Key Effect: Dams expanded snail habitat and cut off migratory routes of their natural predators—large river prawns.
  • “This part of Senegal has among the highest burdens of schistosomiasis anywhere. For rice farmers, it's an occupational hazard.” – Jonathan Lambert [05:43]
• Farmers like Jibi Ja report chronic illness from this “always happens to us since we are in the water for most of the time.” [05:53]

3. The Fish Solution: Rice-Fish Co-culture

• Introducing Fish:
  • Researchers are testing two species: African bony tongue (Heterotis niloticus) and tilapia, deployed across 60 rice fields.
  • Fish are meant to restore balance by replacing lost snail predators.
  • “It's a species which can eat a lot of snails per day.” – Momi Secondao, environmental engineer [06:50]
• Dual Roles of Fish:
  • Bony tongue: Eats snails, potentially lowering disease risk.
  • Tilapia: Competes with snails for food and provides natural fertilizer through their waste—boosting rice yields.

4. Experimental Logistics

• Fish Sourcing:
  • Tilapia are farm-raised and transported in large tanks to rice fields.
    • “The truck actually stalled out a few times as we were trying to leave because it was so heavy.” – Jonathan Lambert [09:57]
  • Bony tongues must be caught as juveniles in rivers, making them harder to source.
• Introduction Process:
  • Fish are gently eased into fields using buckets to minimize stress [10:47].
  • “They don't feed them anything. The idea is to just let the fish do their thing.” – Jonathan Lambert [11:01]

5. Tracking Success: What Are The Scientists Measuring?

• Snail populations before and after introduction.
• Rice growth metrics, including yield (measured by drones).
• Socioeconomic benefits—for example, increased rice output and household income.

6. Results So Far & Farmers' Experiences

• Promising Preliminary Data:
  • A recent pilot study showed a 25% increase in rice yields, income boosts, and a slight reduction in snail populations.
    • “They found that adding fish boosted rice Yields by about 25%. It also significantly boosted income and slightly reduced snail numbers.” – Jonathan Lambert [12:00]
• Farmer Testimonial:
  • Abu Diallo increased sales from 60 to 90 bags of rice annually, renovated his house, and bought livestock with added income.
  • “He says the fish he gets from his farm taste better than those he gets at the market and are obviously cheaper too.” – Jonathan Lambert [12:32]

7. Addressing Possible Ecological Concerns

• Risk of using biological solutions to control biological problems noted.
  • “Because the rice farms are kind of like a self-contained unit, there's less of a... It's not like the fish are going to be like jumping out and causing other problems.” – Jonathan Lambert [08:56]
• Fields are artificial and contained, reducing the risk of invasive spread.

8. Cultural Fit and Scale-up Potential

• Fish-and-rice is a natural pairing for Senegalese diets (national dish: chebbujen).
  • “Senegalese people love a lot fish. We eat it every day. Rice and fish.” – Momi Secondao [13:34]
• Researchers believe local acceptance (and cultural excitement) bode well for expansion, although broad adoption will require aquaculture industry growth and farmer training.

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Notable Quotes & Memorable Moments

• “So how are they solving these problems? —With fish.” – Jonathan Lambert [01:03]
• “It's not great. When I was in Senegal, Kayla Kaufman, a Stanford disease ecologist who works on the project, dug up some of these snails in a rice field to show me.” – Jonathan Lambert [04:07]
• “But their main job isn't reducing schisto, it's pooping.” – Jonathan Lambert [08:02]
• “You came to the right place, John.” – Regina Barber (joking about fish fertilizer) [08:07]
• “Plop the fish into the rice fields?” – Regina Barber [10:37]
  “It's more like gently ease the fish into their new home.” – Jonathan Lambert [10:44]
• “You are in Senegal... If you grow rice and fish in the same area, you have this just meat to add vegetables.” – Momi Secondao [13:34]
• “Did you have some of this national dish?” – Regina Barber
  “I actually did have some chebbujen, and it was incredible. Honestly, it was so good.” – Jonathan Lambert [14:38]

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Timestamps for Key Segments

• [01:03] – Introducing “the fish solution”
• [03:22] – How rice farming is possible in the Sahel, thanks to dams
• [04:01] – Explanation of schistosomiasis and its cycle
• [05:03] – Dams’ ecological impacts (loss of prawns, rise in snails)
• [06:39] – Fish species and how they target the disease
• [08:02] – The fertilizing effect of tilapia waste
• [09:38] – Sourcing and transporting the fish
• [10:44] – Introducing fish to rice fields
• [11:25] – Scientific data collection and what’s being measured
• [12:00] – Results from earlier pilot studies
• [12:23] – Farmer testimonials and economic outcomes
• [13:34] – Cultural resonance and future scaling
• [14:38] – Host’s personal tasting experience of chebbujen

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Tone & Style

The episode is conversational, warm, and peppered with humor and curiosity, capturing the wonder of science and the enthusiasm of the researchers and locals involved. Regina brings a sense of excitement and relatability, while Jonathan shares detailed observations from his field experience, balancing scientific rigor with local stories.

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In summary:
Senegal’s innovative rice-fish farming experiment is poised to reduce disease, improve yields, and increase incomes—just by letting fish do what fish do best. Early data are hopeful, farmers are excited, and the nation’s love of fish and rice makes this scientific solution a potentially sustainable and very local success story.

Transcript

[Charles Schwab Announcer]

This message comes from Charles Schwab with their original podcast, Choiceology. Choiceology is a show about the psychology and economics behind people's decisions. Download the latest episode and [e-mail] podcast.

[Regina Barber]

You're listening to Shortwave from NPR. Hey, Shortwavers. Regina Barber here, and today I'm joined by NPR global health reporter Jonathan Lambert. Hey, John.

[Jonathan Lambert]

Hey, Gina.

[Regina Barber]

So you're here today with a story from Senegal.

[Jonathan Lambert]

Yeah, I traveled there earlier this year to witness the early stages of an ambitious experiment.

[Regina Barber]

Okay, I'm very curious. What is this experiment?

[Jonathan Lambert]

So a team of Senegalese and international researchers are trying to see if they can solve three big problems that are affecting rice farmers and Senegal more broadly with one simple solution.

[Charles Schwab Announcer]

Ooh.

[Regina Barber]

Okay. Before the solution, what are the problems?

[Jonathan Lambert]

A debilitating disease, the need to boost rice production in Senegal, and poverty among rice farmers in the country.

[Regina Barber]

Ooh. Okay, so how are they solving these problems?

[Jonathan Lambert]

With fish.

[Regina Barber]

I like it. Okay, fish. Tell me more.

[Jonathan Lambert]

Yeah, specifically putting fish, like hundreds of fish of a couple of different species into rice farms.

[Regina Barber]

That's so cool.

[Jonathan Lambert]

Yeah, it's really cool. The research team behind this has done smaller pilot studies that showed this could be promising. And this year, they're really scaling up the experiment and testing it out across 60 rice fields. Okay, so I tagged along with the team as they set out before dawn from San Louis, which is this town on the coast of Senegal, to pick up these fish and deliver them to one of those farms about 100 some miles south of the Sahara Desert.

[Regina Barber]

Wow. You became a fishmonger. Sort of.

[Jonathan Lambert]

Kind of.

[Regina Barber]

So today on the show, how putting fish in rice farms could be a win, win, win for fighting a debilitating disease, boosting rice production, and reducing poverty

[Jonathan Lambert]

and why rice farming helped fuel a surge of this disease in the first place.

[Regina Barber]

You're listening to Short Wave, the science podcast from npr.

[Charles Schwab Announcer]

This message comes from Charles Schwab with their original podcast, Choiceology. Choiceology is a show about the psychology and economics behind people's decisions. Download the latest episode and [e-mail] podcast

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[Regina Barber]

Okay, so, John, I want to back up to something you said earlier about these rice fields being pretty close to the Sahara. I thought rice needed lots of water. So isn't. Is this area, like, maybe too deserty to grow rice?

[Jonathan Lambert]

Yeah, that's a great question. This region is called the Sahel, and it's really hot and dry and dusty. The exception is right around the Senegal River. It's still pretty hot, but it's a lot greener. And a lot of that green is from rice farms. But it wasn't always this way.

[Regina Barber]

So what changed that?

[Jonathan Lambert]

So a series of dams that were built in the 1980s. Before the dams, there just wasn't really enough water to support rice farming during the dry season. After the dams, it became a lot easier, and rice farming flourished. But the dams also had a major unintended consequence. A surge in schistosomiasis.

[Regina Barber]

I have no idea what that word means. What is it?

[Jonathan Lambert]

It's a disease that's caused by this parasitic worm that spends part of its life in freshwater snails.

[Regina Barber]

Oh, no.

[Jonathan Lambert]

Yeah. It's not great. When I was in Senegal, Kayla Kaufman, a Stanford disease ecologist who works on the project, dug up some of these snails in a rice field to show me.

[Regina Barber]

Okay, so what did they look like?

[Jonathan Lambert]

It's basically like your standard snail, but they can be pretty tiny, but they're still really dangerous. The parasite reproduces asexually inside the snail and then can slink out into the water by the thousands.

[Regina Barber]

They then try to find a person that's wading in the water, like a rice farmer, and they burrow through that person's skin and then go on this complicated path through their body. This is horrifying.

[Jonathan Lambert]

Yeah. And ultimately, the worms lay eggs in a person's intestines or urinary tract, and that can cause a slew of problems, from stomach pain to bladder cancer.

[Regina Barber]

Oh, my gosh. This is like a horror movie. Okay, and because the dams were built to keep around more water, did that make the disease worse?

[Jonathan Lambert]

Yeah, totally. Okay, not just because the dams meant there was a lot more water and thus a lot more habitat for the snails, but the dams also cut off the migration route of a key predator. Prawns.

[Regina Barber]

So these prawns would be eating these worms?

[Jonathan Lambert]

Yes. Yeah. So they were a major predator. And they're not like small prawn. They're like kind of big, like big crayfish. And they're pretty fierce snail eaters.

[Regina Barber]

Wow.

[Jonathan Lambert]

And before the dams, they helped keep snail numbers in check. But after, Kaufman says that prawn numbers fell, and fewer prawns meant more snails and more schisto.

[Regina Barber]

The link between dam construction and increased

[Momi Secondao]

schistosomiasis is really strong.

[NPR Sponsor Announcer]

Now.

[Jonathan Lambert]

This part of Senegal has among the highest burdens of schistosomiasis anywhere. For rice farmers, it's an occupational hazard. I spoke to one named Jibi Ja at the farm that he's worked for four decades. He's saying that this always happens to us since we are in the water for most of the time. He's had bad stomach aches, diarrhea, fever. It can affect him for weeks to months at a time.

[Regina Barber]

It sounds awful. How is it treated?

[Jonathan Lambert]

So there is medicine to treat it, but he says it's hard for him to get it. Partially that's because he's in a really rural part of Senegal, and partially it's just expensive to get the drug, and it doesn't prevent reinfection. So farmers, because they're always going back into the water, they just get it again and again.

[Regina Barber]

Oh, my gosh.

[Jonathan Lambert]

That's where the fish solution I hinted at earlier comes in. One of the species researchers are testing out is called African bony tongue, or Heterodis.

[Regina Barber]

I love it.

[Jonathan Lambert]

Okay, tell me more. They're these big, kind of gnarly looking fish, almost like prehistoric. Momi Secondao, an environmental engineer on the project, told me that they're perfect for the job.

[Momi Secondao]

It's a species which can eat a lot of snails per day.

[Regina Barber]

Okay, so the fish are kind of like replacing the prawns as a predator.

[Jonathan Lambert]

Yeah, exactly. Actually, some of the same researchers tried stocking some parts of the river that lost prawns with new ones earlier, like several years ago. But raising all those prawns proved really tricky, and the researchers think that raising all these fish will be easier, and the hope is that they'll eat enough snails in the rice farm to lower the risk of schisto. Momi and her colleagues take measurements of the snail density in farms before adding the fish, and they'll do that again at the end of the season later this year. But getting these honkers into the rice farm is challenging.

[Momi Secondao]

Yes, the Heterodis is very crazy. Very, very, very hard to catch.

[Regina Barber]

Wow. I hear all the splashing. Okay, so you mentioned multiple species are Being added.

[Jonathan Lambert]

Yeah. So the other species is tilapia, and hundreds of tilapia will be added to each field.

[Regina Barber]

Tilapia is such a, like a staple for food. Right. Do they eat snails too?

[Jonathan Lambert]

Not really. They do eat a lot of the same stuff that snails eat, like algae. And so that competition could hurt the snails.

[Regina Barber]

Okay.

[Jonathan Lambert]

But their main job isn't reducing schisto, it's pooping.

[Regina Barber]

You came to the right place, John.

[Jonathan Lambert]

Yeah. Here's Momi again.

[Momi Secondao]

The feces of the fish, which is very important. It's natural fertilizers.

[Jonathan Lambert]

More fertilizer should mean more rice. That'd be great for the farmers and for Senegal as a whole. Cause even with all the rice production that's happening in the Senegal River Valley, it's not enough to meet demand. The country still imports about half the rice it eats. And as a final bonus, the farmers can eat the fish themselves or sell them at the end of the season.

[Regina Barber]

I love this. Is there any cons to this? Because, like, you know how in other countries you introduce a species to get rid of the other species, and then it's just like a, you know, invasive thing forever.

[Jonathan Lambert]

That is a common pitfall of many attempts to try to solve a biological problem with a biological solution.

[Regina Barber]

Exactly.

[Jonathan Lambert]

This one, when I posed this question to the researchers and they told me that because the rice farms are kind of like a self contained unit, there's less of a. It's not like the fish are going to be like jumping out and causing other problems. And the.

[Regina Barber]

It's already human made too.

[Jonathan Lambert]

Yeah, yeah. It's like an artificial place. So they're adding in this biological solution. That doesn't mean that there aren't things that could go wrong. But think that that potential is less because it's already in this sort of artificial, enclosed place.

[Regina Barber]

Okay. All right. Well, at the beginning of the story, you talked about how you went somewhere to get the fish and you brought it to the rice paddies. So, you know, in general, where are these fish coming from?

[Jonathan Lambert]

Yeah. So the day that I was with the team, we set off from San Luis, which is right on the coast, to a town called Dagana, which is about two hours away to a fish farm. And there a fish farmer raises these tilapia. And the team caught nearly 2,000 of them and loaded them up into this big green tank on the back of a pickup truck.

[Regina Barber]

So you were in this truck?

[Jonathan Lambert]

I was in the truck. It actually stalled out a few times as we were trying to leave because it was so heavy, because it was so heavy, and it's, like, really hot. And so I was worried, and the researchers were worried that it would, like, the fish would bake in the sun. So we were kind of on, like, it was a tight timeline to get the fish from the farm to the rice farm.

[Regina Barber]

Okay.

[Jonathan Lambert]

But we made it awesome.

[Regina Barber]

Okay, what about the other fish, the snail eaters?

[Jonathan Lambert]

So those are actually trickier to get. They live naturally in rivers, and people have to go out and catch them, usually as juveniles, and then raise them from there. Like, it's harder to raise them in a fish farm setting. And along the way, we stop at the smaller field site managed by the team to grab a few of those big fish.

[Regina Barber]

Okay. So you take these fish, you drive up to the farm. What do you do now? Do you just, like, plop the fish into the rice fields?

[Jonathan Lambert]

It's more like gently ease the fish into their new home.

[Regina Barber]

How do you do that?

[Jonathan Lambert]

It's basically the same principle. They take them in buckets and, like, slowly submerge the buckets and then give the fish time to, like, swim out when they feel ready. It usually takes, like, five to 10 minutes.

[Regina Barber]

And what do the farmers feed them?

[Jonathan Lambert]

Nothing. They don't feed them anything. The idea is to just kind of let the fish do their thing because

[Regina Barber]

they have to eat snails and algae and poop.

[Jonathan Lambert]

Exactly.

[Regina Barber]

And then hopefully be dinner for the farmers.

[Jonathan Lambert]

Exactly. And this is happening across 60 rice fields for this whole season. And in each of those fields, the researchers will be collecting a ton of data. They're tracking the snails. They're measuring rice growth with drones.

[Charles Schwab Announcer]

Oh.

[Jonathan Lambert]

And they're closely tracking how the farmers are using the fish.

[Regina Barber]

Okay. So the hope is that this reduces this disease spreading snail population. It'll boost the rice and also maybe the farmer's income.

[Jonathan Lambert]

Yeah. Yeah.

[Regina Barber]

Okay.

[Jonathan Lambert]

And they have more reasons to be optimistic. For one, fish and rice have been raised together for centuries in Asia, and the benefits to rice yields are well documented there. It's pretty rare in Africa. But the researchers have done this experiment on a much smaller scale over the past few years, and they actually published some promising data just a couple of months ago.

[Regina Barber]

Ooh, what did they find?

[Jonathan Lambert]

So they found that adding fish boosted rice Yields by about 25%. It also significantly boosted income and slightly reduced snail numbers. The sample size was kind of small, so that's why they're scaling up the experiment this year. And when I was in Senegal, I got to talk to some of the farmers who'd already tried this out. One farmer named Abu Diallo told me that it changed his life.

[Regina Barber]

Wow. How did it change his life?

[Jonathan Lambert]

So before, he sold about 60 bags of rice a year, but after adding the fish, he sold about 90 bags a year.

[Charles Schwab Announcer]

Whoa.

[Regina Barber]

That's a lot.

[Jonathan Lambert]

Yeah. And that extra income made a big difference for him. He says he's been able to renovate his home and buy a flock of sheep. Plus, he says the fish he gets from his farm taste better than those he gets at the market and are obviously cheaper too.

[Regina Barber]

Wow. Okay. So what about this disease? This your nickname for it? Schisto?

[Jonathan Lambert]

Yeah. He hasn't gotten it since, but it's hard to say if that's because of the fish or not. That's why the researchers are expanding the scope of the experiment this year to really try to nail down the precise benefits. Understanding what works and what doesn't work will help the researchers scale up this practice even more. They told me that's really their ultimate goal.

[Regina Barber]

Okay, so, but how would that work? You obviously need a lot more fish.

[Jonathan Lambert]

Yeah, you would need a lot of fish, and there'd have to be a lot of growth in that aquaculture industry to produce all those fish. And farmers would need a lot of help in getting up to speed on how to do this. But Momi thinks the potential is there. In part. She thinks that because this is a particularly Senegalese solution to these problems.

[Momi Secondao]

You are in Senegal. Senegal. Senegalese people love a lot fish. We eat it every day. Rice and fish.

[Jonathan Lambert]

It's actually the national dish called chebbijen.

[Momi Secondao]

If you grow rice and fish in the same area, you have this just meat to add vegetables.

[Jonathan Lambert]

She says that farmers have been pretty willing to try it out, in part because of that cultural connection. If they can back that up with some science that says it helps prevent schisto and helps them grow more rice and make more money, she thinks it could really take off.

[Regina Barber]

John, thank you so much for bringing us this reporting.

[Jonathan Lambert]

Thanks for having me.

[Regina Barber]

This episode was produced by Rachel Carlson, Hannah Chin, and Juan Diego Ramirez. It was edited by our showrunner, Rebecca Ramirez.

[Jonathan Lambert]

Tyler Jones checked the facts. Jimmy Keeley was the audio engineer. I'm Jonathan Lambert.

[Regina Barber]

And I'm Regina Barber. Thank you for listening to Showrunners Wave, the science podcast from npo. Did you have some of this national dish?

[Jonathan Lambert]

I actually did have some chevid zhen, and it was incredible. Honestly, it was so good.

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