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

In Senegal, rice farmers are trying to kill three birds with one stone – er, fish. Rice and fish are already a natural combination; they’re even the main ingredients of thieboudienne, the delicious national dish. But could that combination also reduce a debilitating disease, boost food security AND help farmers make more money? A team of researchers are conducting an ambitious experiment to see whether growing rice and fish together can be a win-win-win for Senegal, and NPR’s Jonathan Lambert https://www.npr.org/people/703751120/jonathan-lambert came along for the ride. Interested in more science-based biological solutions? Email us your question at [email protected] mailto:[email protected]. Support public media with NPR+ and enjoy perks for over 25 podcasts like this one. It includes perks like bonus episodes, early access, archive access, curated playlists and sponsor-free listening. Learn more at plus.npr.org http://plus.npr.org. See pcm.adswizz.com https://pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. NPR Privacy Policy https://www.npr.org/about-npr/179878450/privacy-policy

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• 0:18Speaker 01

  You're listening to Short Wave from NPR.

• 0:23Speaker 01

  Hey, Short Waver, it's Regina Barber here. And today I'm joined by NPR Global Health Reporter Jonathan Lambert. Hey, John.

• 0:29Speaker 02

  Hey, Gina.

• 0:30Speaker 01

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

• 0:33Speaker 02

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

• 0:39Speaker 01

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

• 0:42Speaker 02

  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.

• 0:52Speaker 01

  Ooh, OK, before the solution, what are the problems?

• 0:56Speaker 02

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

• 1:02Speaker 01

  Ooh, OK, so how are they solving these problems?

• 1:05Speaker 02

  With fish.

• 1:08Speaker 01

  I like it. OK, fish, tell me more.

• 1:11Speaker 02

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

• 1:17Speaker 01

  That's so cool.

• 1:18Speaker 02

  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.

• 1:29Speaker 01

  OK.

• 1:30Speaker 02

  So I tagged along with the team as they set out before dawn from San Luis, 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.

• 1:42Speaker 01

  Wow, you became a fishmonger, sort of.

• 1:45Speaker 02

  Kind of.

• 1:46Speaker 01

  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.

• 1:56Speaker 02

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

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

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• 3:35Speaker 01

  OK, 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 this area, like, maybe too desert-y to grow rice?

• 3:49Speaker 02

  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.

• 4:00Speaker 01

  OK.

• 4:00Speaker 02

  And a lot of that green is from rice farms. But it wasn't always this way.

• 4:05Speaker 01

  So what changed that?

• 4:07Speaker 02

  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.

• 4:25Speaker 01

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

• 4:29Speaker 02

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

• 4:35Speaker 01

  Oh, no.

• 4:36Speaker 02

  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.

• 4:45Speaker 01

  OK, so what did they look like?

• 4:47Speaker 02

  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.

• 4:59Speaker 03

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

• 5:08Speaker 01

  This is horrifying.

• 5:09Speaker 02

  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.

• 5:19Speaker 01

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

• 5:31Speaker 02

  Yeah, totally.

• 5:31Speaker 01

  OK.

• 5:32Speaker 02

  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.

• 5:43Speaker 01

  So these prawns would be eating these worms?

• 5:46Speaker 02

  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.

• 5:54Speaker 01

  Wow.

• 5:55Speaker 02

  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.

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  The link between dam construction and increased schistosomiasis is really strong.

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  Now, 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 Jibby Ja, at the farm that he's worked for four decades.

• 6:27Speaker 02

  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.

• 6:38Speaker 01

  It sounds awful. How is it treated?

• 6:41Speaker 02

  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 reinfections, so farmers, because they're always going back into the water, they just get it again and again.

• 6:58Speaker 01

  Oh, my gosh.

• 6:59Speaker 02

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

• 7:07Speaker 01

  I love it.

• 7:07Speaker 02

  Yeah.

• 7:08Speaker 01

  OK, tell me more.

• 7:08Speaker 02

  They're these big, kind of gnarly-looking fish, almost like prehistoric.

• 7:12Speaker 01

  Cool.

• 7:13Speaker 02

  Mo Mi Sekendaw, an environmental engineer on the project, told me that they're perfect for the job.

• 7:18Speaker 04

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

• 7:23Speaker 01

  OK, so the fish are kind of like replacing the prawns as a predator?

• 7:27Speaker 02

  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.

• 7:37Speaker 01

  OK.

• 7:37Speaker 02

  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. Mo 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.

• 8:01Speaker 04

  Yes, and the heterotis is very, very crazy, very, very, very hard to catch.

• 8:08Speaker 01

  Wow, I hear all the splashing. OK, so you mentioned multiple species are being added.

• 8:13Speaker 02

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

• 8:19Speaker 01

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

• 8:23Speaker 02

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

• 8:30Speaker 01

  OK.

• 8:30Speaker 02

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

• 8:35Speaker 01

  You came to the right place, John.

• 8:38Speaker 02

  Yeah, here's Momi again.

• 8:39Speaker 04

  The fishes of the fish, she is very important. Natural fertilizers.

• 8:44Speaker 02

  More fertilizer should mean more rice. That'd be great for the farmers and for Senegal as a whole. Because 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.

• 9:04Speaker 01

  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?

• 9:16Speaker 02

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

• 9:23Speaker 01

  Exactly.

• 9:24Speaker 02

  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 fish-

• 9:38Speaker 01

  It's already human-made, too.

• 9:40Speaker 02

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

• 9:55Speaker 01

  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?

• 10:05Speaker 02

  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.

• 10:24Speaker 01

  So you were in this truck?

• 10:25Speaker 02

  I was in the truck. It actually stalled out a few times as we were trying to leave.

• 10:28Speaker 01

  Because it was so heavy?

• 10:29Speaker 02

  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.

• 10:41Speaker 01

  Okay.

• 10:41Speaker 02

  But we made it.

• 10:42Speaker 01

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

• 10:45Speaker 02

  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.

• 10:55Speaker 01

  Okay.

• 10:55Speaker 02

  It's harder to raise them in a fish farm setting. And along the way, we stopped at this smaller field site managed by the team to grab a few of those big fish.

• 11:04Speaker 01

  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?

• 11:11Speaker 02

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

• 11:14Speaker 01

  Okay, how do you do that?

• 11:15Speaker 02

  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.

• 11:27Speaker 01

  And what do the farmers feed them?

• 11:29Speaker 02

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

• 11:34Speaker 01

  Because they have to eat snails and algae and poop.

• 11:37Speaker 02

  Exactly.

• 11:37Speaker 01

  And then hopefully be dinner for the farmers.

• 11:40Speaker 02

  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.

• 11:53Speaker 01

  Oh.

• 11:54Speaker 02

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

• 11:57Speaker 01

  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?

• 12:07Speaker 02

  Yeah, yeah.

• 12:07Speaker 01

  Okay.

• 12:08Speaker 02

  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.

• 12:26Speaker 01

  Ooh, what did they find?

• 12:28Speaker 02

  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 is 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.

• 12:51Speaker 01

  Wow, how did it change his life?

• 12:52Speaker 02

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

• 12:59Speaker 01

  Whoa, that's a lot.

• 13:00Speaker 02

  Yeah, and that extra income made a big difference for him.

• 13:08Speaker 02

  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.

• 13:17Speaker 01

  Wow. Okay, so what about this disease, this, your nickname for it, schisto?

• 13:22Speaker 02

  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 will help the researchers scale up this practice even more. They told me that's really their ultimate goal.

• 13:40Speaker 01

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

• 13:44Speaker 02

  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.

• 14:02Speaker 04

  You are in Senegal. Senegal, Senegal is people love a lot fish. We eat it every day, rice and fish.

• 14:09Speaker 02

  It's actually the national dish called chébige.

• 14:11Speaker 01

  Oh.

• 14:12Speaker 04

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

• 14:21Speaker 02

  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.

• 14:34Speaker 01

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

• 14:37Speaker 02

  Thanks for having me.

• 14:40Speaker 01

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

• 14:48Speaker 02

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

• 14:53Speaker 01

  And I'm Regina Barber. Thank you for listening to Short Wave, the science podcast from NPR.

• 15:03Speaker 01

  Did you have some of this national dish?

• 15:05Speaker 02

  I actually did have some chébige, and it was incredible, honestly. It was so, it was so good.

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