This is a transcript of the Gastropod episode, Dinner Plate Invasion: Lionfish, Tiger Shrimp, and Feral Pigs, Oh My!, first released on January 14. It is provided as a courtesy and may contain errors.
BUN LAI: Okay. Yeah. Dig in. Let me know what you think.
CYNTHIA GRABER: I—I so rarely eat something where I absolutely like—
NICOLA TWILLEY: I have no clue.
GRABER: I have no idea what it is.
TWILLEY: No clue. I don’t even know where to start.
GRABER: I want to start with I think this over here.
TWILLEY: Smells incredible. Mmm. Texture.
GRABER: Mmm. It feels a little bit cartilaginous.
LAI: Yeah. Very accurate description of that.
TWILLEY: It’s some kind of like, um, like, mmm, invertebrate adjacent thing. What, what—like, what is it? What is it? Are we in the jellyfish realm?
LAI: You hit the target right on the head. It’s an invasive jellyfish caught in Georgia.
TWILLEY: Yep, I guessed right—that was a jellyfish on our plates, and the chef who prepared it for us is called Bun Lai.
GRABER: Bun is the chef and owner of Miya’s Sushi in New Haven, Connecticut. And we are Gastropod, the podcast that looks at food through the lens of science and history, I’m Cynthia Graber.
TWILLEY: And I’m Nicola Twilley. And although I didn’t admit it at the time, I had a slight advantage in our guessing game, because I’ve eaten jellyfish before, when I was in China—not this specific jellyfish, but I think they’re all kind of similar—
GRABER: I had no idea that you had a bit of a leg up on me there, I’d never eaten jellyfish before. But I did really like it.
LAI: Yeah, it’s all texture and the flavor that you want to put onto it. It’s one of my favorite foods.
GRABER: Oh, my gosh. It’s totally addictive. Like it’s crunchy and spicy and savory and like I could just eat this forever.
TWILLEY: So, yes, today’s episode is the jellyfish content you’ve all been begging for. Just kidding.
GRABER: It’s actually about something else Bun said when he told us what we were eating—he pointed out that it’s an invasive jellyfish caught off the coast of Georgia. This episode we are all about eating invasives.
TWILLEY: Eating them, yes, but also figuring out what they are? What makes a species invasive and why might we want to get rid of invasive species?
GRABER: And is eating them really the best way to do it? Like, should we all be eating jellyfish and Japanese knotweed?
TWILLEY: Or, you know, feral pigs. That we shoot down from helicopters. On reality TV.
PIG HUNG FOOTAGE: I want to just come straight up and you come right at the pig and shoot it. Lock and load boys, lock and load. We’ll try any way possible to get rid of the pigs. It’s a very serious issue for us.
GRABER: Will that stop the pigs from ravaging landscapes around the US and causing more than a billion dollars in damages each year? Stay tuned for all that and more!
GRABER: Sara Kuebbing is a conservation biologist at the University of Pittsburgh.
TWILLEY: Joe Roman is also a conservation biologist at the University of Vermont.
GRABER: And we asked them what seems like the most basic question of all—what makes a species invasive?
SARA KUEBBING: Actually defining invasive species is not really that trivial. But, at its base, an invasive species is a species that is not native to a particular location.
JOE ROMAN: So you have a species that’s taken from its native environment to a new place.
KUEBBING: And it has been brought by humans. And specifically by humans.
TWILLEY: No one knows what the first invasive species was—the first plant or animal that a human moved to a new environment. But Sara says we’ve been doing it forever, as long as we’ve been on the move.
ROMAN: And the question is, does it become established, right? So you can think of a cow, you can bring a cow to a new area. And it’s not going to escape. And it’s not an invasive species.
KUEBBING: Actually most of our domesticated crops and domesticated animals don’t live outside of human cultivation. And so for that reason, we don’t see, you know, no one talks about the wild corn population that is ravaging the Midwestern prairies because corn doesn’t spread beyond farm fields.
ROMAN: But you bring something like a Norway rat into a new area, it goes beyond where it’s introduced. Populations get high. And it has an impact on native species. So that would be the broad definition of invasive—one that is outside of its native range and has an impact on other species in the new area.
GRABER: That impact can be terrifying. Those rats Joe mentioned hid on European boats as they traveled around the world from the 1500s onward. They hopped off the boats onto Pacific Islands, they multiplied super quickly, and they totally decimated local bird and amphibian species. They just ate everything, the rats even ate birds alive, they ate the heads off albatross chicks. The bird populations on the islands dropped by more than 90 percent.
ROMAN: Invasive species have been one of the primary drivers of the extinction crisis, unfortunately, especially on islands. Thousands of bird species, mammals, lizards, insects, mollusks have gone extinct when new species have come to these areas.
TWILLEY: The rats also encouraged fleas and mosquitoes, which brought disease. Invasives can be really harmful to human health too.
ROMAN: It also has a big economic impact. You can think of the effect of invasives on agriculture or in parks and along our coastlines, impacts on recreation.
TWILLEY: Invasive plants can be just as scary. Take Japanese knotweed. It’s a leafy green plant, it kind of grows up in stems like bamboo, and it was brought back from Japan in the 1840s, and sold as a quote “gracious gold-medal winning shrub that grew with great vigor.”
GRABER: It looks kind of pretty when you just see it in the yard—there was a patch of it outside my partner Tim’s old apartment. But it grows with such vigor that it can grow through foundation walls and floors, which of course causes huge damage. In the UK, someone found it pushing through their carpet.
TWILLEY: It’s such a problem in England that some banks won’t issue mortgages to properties that have Japanese knotweed. There is no known herbicide to kill it and if you dig it up and try to get rid of it, you have to dig three feet deep and then dispose of all that earth it in a special location because the government classifies knotweed according to the same rules as low-level nuclear waste
GRABER: In Japan, it’s not such a big deal. There are lots of other native plants that are similarly vigorous that help keep it in check, and there are also plenty of native Japanese pests and plant diseases that can kill it. But we don’t have any of that in Europe or North America.
TWILLEY: So basically, knotweed is a nightmare. And because it grows so fast and so densely, it smothers the native plants, which kills them. And then all the birds, and frogs, and butterflies, and bugs that depend on those native plants are screwed. And then you end up with a giant knotweed wasteland devoid of all other forms of life. More or less.
GRABER: Experts in the UK estimate that to get rid of knotweed would cost about 3 billion dollars. But knotweed costs the UK more than 200 million a year already, just in the damage it causes and trying to manage it.
TWILLEY: This kind of harm—for many people, this is what makes an invasive an invasive, as opposed to just a plant or animal that originally came from somewhere else and has spread out in the landscape.
GRABER: All these non-native species—we bring so many of them with us as we travel, either accidentally or, quite often, on purpose.
KUEBBING: We are continually introducing species. So a human saying, hey, I like that species. I’d like to bring it here to the U.S.
ROMAN: So for a long time, this was seen as a good thing, right? Bring in new species, more diversity, more resources available that we like.
TWILLEY: One of my favorite stories about this involves the introduction of the rainbow trout to the rivers of the Western U.S. in the late 1800s and early 1900s. At the time, native fish were in decline and anyway they’re weren’t seen as quote good sport—the native fish didn’t fight back when you hooked them on the line, and Congress was worried that without fighting fish to catch, American men would lose vigor and virility. So they set about aerially bombing the watersheds of the western U.S. with rainbow trout.
GRABER: Literally, they dropped the fish from planes in the sky—
TWILLEY: Yeah, a lot didn’t make it. But enough did to restore the glory that is American manhood—thank heavens. Unfortunately, the introduction of the rainbow trout was, you guessed it, completely disastrous for native fish and amphibians.
GRABER: But it took a while for people to realize that invasives were as much of a problem as we now know they are. For one, we had to figure out that there was such a thing as extinction—as you listeners might remember from our episode this past fall, where we talked about the concept of eating animals to extinction. The scientific understanding of extinction only emerged in the 1800s. And to make the leap that we were bringing animals with us on our travels, either inadvertently or on purpose, and those new species cause others to go extinct? It just took us a while to grasp that was even a possibility.
TWILLEY: What’s more, for a long time, the prevailing attitude was also, hey, just let the best fish or animal or plant win. If rainbow trout were capable of out-competing native fish, then why wouldn’t we want to have rivers filled with these alpha fish instead?
GRABER: But eventually attitudes started to change.
ROMAN: So Charles Elton wrote one of the early books about animal invasions. I’d say it was around the 1930s. I don’t have the exact date, but he really was one of the first ones to start thinking about this as a science, you know, and to look at what the ecological impacts are, how species have moved around and really get an idea of what we can do perhaps to reverse the spread.
KUEBBING: And so there’s ecologists back to, you know, the 40s and 50s who were writing a lot about invasive species, but their writings didn’t catch on until later when more people started seeing the phenomenon happening.
GRABER: And then the academic field of studying invasive species, trying to figure out what the impact is and how to get rid of them, that didn’t really start for another few decades.
KUEBBING: It really happened in the 70s and 80s with scientists who, working in ecosystems where they had spent their lives doing research, they started noticing that there were these—I don’t even know if they called them non-native. But anyways, these scientists realized that in whatever ecosystem they were in, there were these species that had been introduced relatively recently by humans that were becoming very dominant and causing different levels of harm to those ecosystems. And so they got together in the 80s and they actually formed a working group through the United Nations to start addressing some of those species.
TWILLEY: Today, many people are a little more conscious about just introducing random new species for fun and sport. But Sara says invasions are actually still on the rise, thanks to accidental introductions.
KUEBBING: Where a species accidentally hitches a ride, whether it’s on the hull of a ship or on the outside of an airplane or within all of the cargo and things that we’re shipping globally around the world—we’re introducing species at unprecedented rates. And that’s for aquatic ecosystems, for terrestrial ecosystems, for plants, for animals, for microbes, sort of all of the different organisms. We’re seeing an increase in just those number of species. And I think that it is becoming problematic because invasion is a function of global trade and global trade has really expanded quite rapidly in the past couple decades.
GRABER: Today, there’s a general consensus that invasive species are a huge threat and a growing threat. There’s something called the International Panel on Biodiversity and Ecosystem Services, it’s a project of the United Nations. They put out a new report in May 2019.
KUEBBING: And they listed five things as like the leading global threats to biodiversity worldwide and invasive species made that top five list.
TWILLEY: So people like Sara and Joe and their colleagues are really worried—invasives are a huge problem and also, unfortunately, a really difficult one to tackle.
GRABER: And they and other scientists like them have been trying to figure out the best ways to control the spread of these species or get rid of them entirely.
TWILLEY: And, as it happens, one method involves our favorite activity: eating!
GRABER: And this gets back to why we were eating jellyfish with Bun Lai.
TWILLEY: This all starts in the 90s, Joe was studying for his PhD and he was focused on an invasive species called the European green crab
ROMAN: So this crab, as the name implies, it’s native to Europe and North Africa and is now found in every continent in the world except for Antarctica because it’s too cold there. First got into the area around New York, Massachusetts, in the early eighteen hundreds and has since expanded its range throughout the Canadian Maritimes. And I could tell almost immediately when I was an area where the crab had arrived or it hadn’t, because there was a suite of different native crabs, rock crabs in that area. There was abundant eel grass, that the ecosystem looked very different before that species came arrived.
TWILLEY: But when he got to an area where the European crab had arrived, all those species, the eel grass and the native crabs—they were gone.
GRABER: Joe was traveling up the coast and studying these crabs. He ended up in Nova Scotia. And one day he was on the shore there collecting crabs.
ROMAN: I noticed there was someone else flipping rocks like I was. He didn’t really look like a biologist. He had a big white bucket, and I went over and talked to him and he was collecting European periwinkle, which is another invasive species that overlaps in the intertidal with European green crab. And it gave me an idea that here was this guy was harvesting this invasive species. And actually the more he took out of that area, the better. The better for native species. As opposed to what I do mostly as a conservation biologist is try to convince people to reduce our appetites.
TWILLEY: This was Joe’s breathrough moment. He realized wow: for a change, I could tell people to harvest a species—and eat as much of it as they want! Normally conservationists working in a marine environment are constantly telling us not to eat this delicious fish or that delicious crustacean.
GRABER: But Joe suddenly realized what he was considering was the exact opposite. Joe knew, as all you listeners know from our extinction episode, that we humans can be ravenous. We can easily eat species to death. We’ve done it plenty of times—the mammoth, the passenger pigeon, silphium. So why not green crabs?
ROMAN: So actually that within that day or the next day, I collected some green crabs and some periwinkle and cooked them up at at the lodging where I was up in Nova Scotia. And it was actually delicious. I’m not really a chef, but, you know, if you have good fresh ingredients that come right out of the ocean, you almost can’t go wrong, especially with something like periwinkle, which are snails, because it’s as simple as boiling them and they’re briny and almost like eating, if you like the taste of clams, really, really nice taste. And the European green crabs, if you can find them as soft shells, they’re just as good as blue crabs, the typical soft shell you’ll get in the store. Except, you know, if you’re pulling it right out of the ocean and and cooking up an hour or two later, you really can’t beat it.
TWILLEY: Joe is not a bad cook, obviously, but he’s a conservation biologist, not a chef. Which is exciting, because if European green crabs taste good when he makes them, how delicious could they be in the hands of a professional?
ROMAN: Right. I’m thinking, well, why don’t I reach out to chefs around the country to help put together some recipes?
TWILLEY: Which he did. And some chefs got on board and Joe got some press about his idea to eat invasive species.
GRABER: At around the same time, chef Bun Lai had a crab breakthrough of his own. He hadn’t yet been in touch with Joe—but one day he was spending time out along the shoreline in Connecticut with a friend.
LAI: And we were flipping rocks and we saw these crabs that we had never seen before scurrying around all over the place. And then we looked up what the crab was and it turned out to be an invasive species. And it just made sense. It clicked.
GRABER: Just like Joe, Bun realized, he could eat these. He could cook these. He could serve these—his customers could eat as much as they wanted.
TWILLEY: Bun Lai didn’t start out as a chef focused on serving invasive species. It was more that he just took over the family business.
LAI: I’m a chef at Miya’s Sushi, started by my mom in 1982. It’s a little hole in the wall sushi restaurant in New Haven, Connecticut. Back in the day it was the first sushi bar in Connecticut.
GRABER: Bun told us that his mom wanted to do something new, and cook the food that she loved from her childhood home in Japan.
LAI: And when I was growing up here, the Japanese restaurants that existed were few and far between, but they were mostly like Hibachi style, Benihana, Irakyoke. Like entertainment venues. And she wanted something that was much more earnest and genuine to what she remembered Japan and her cuisine to be like.
TWILLEY: She called her restaurant Miya’s Sushi. And she ran it herself, as well as bringing up Bun and his siblings. And that’s how Bun ended up in the kitchen, just helping out.
LAI: So really single digit when my mom was really getting Miya’s off the ground, when she was catering out of a Yale apartment with a four burner electric stove. And I’ve been following her around and trying to help her since then. And since then, I’ve been in the way. And we still butt heads.
GRABER: Bun hadn’t intended to take over the restaurant. But sushi took off in the late 80s and early 90s, and Bun’s mom suddenly had lots of competition. So Bun started to work on marketing and then he dropped out of college and spent more and more time in the restaurant. And eventually he did, in fact, take it over.
TWILLEY: But by the late 90s, people were starting to realize that a lot of the seafood in sushi was in short supply. And those classic sushi rolls and sashimi dishes—maybe they weren’t the most sustainable way to eat. Bun was one of the first sushi chefs in the U.S. to really understand that and do something about it.
GRABER: First, in 1999, Bun introduced an entirely plant-based sushi menu, which at the time was pretty revolutionary. And then a few years later, after his crab revelation, he turned to sustainable sources of seafood. Especially invasive species.
LAI: Though my palate isn’t that expansive, it is much more adventurous than the average person. And coupled with the possibility of doing something that actually matters, which is reconfiguring the way we look at food, you know, in a way that’s good for the environment. It made me very excited to do it.
GRABER: In 2005, Bun created the first sushi menu in the world, as far as we know, that was dedicated to eating invasive species. And it featured invasive crabs. Turns out that New England is infested with not just one but two species of invasive crabs, the European green ones that Joe studies, and another one called the Asian shore crab.
LAI: The Asian shore crab that we take, we lacto-ferment it in a solution, a salty solution, that’s a reminiscent in spices to Old Bay. You know, one of the most famous crabs around Chesapeake is served with Old Bay seasoning. But putting in that salty solution allows it to also lacto-ferment. So when you do that, you add layers and layers of different flavors to it, too. So in order to get there, it took years and years of experimenting and, and serving it kind of in a way that’s okay, to what I think today is extraordinary.
TWILLEY: Bun has made his name serving these incredibly creative menus based on invasive species. Meanwhile, Joe went on to found an entire organization that popularized this idea—it’s called Eat the Invaders. By the 2010s, eating invasive species was an idea that was really getting some momentum.
KUEBBING: Yeah. I heard about the approach of eating invasives probably about a decade ago when I was in graduate school and I was studying in the research lab of an invasion biologist at the University of Tennessee. And so my colleagues all thought and talked about invasive species sort of nonstop.
GRABER: As they talked, Sara realized she’d eaten invasives plenty of times before grad school, back when she worked in land management in Vermont.
KUEBBING: I had made garlic mustard pesto many times and I had brought it out to volunteers that I worked with with crackers
TWILLEY: Garlic mustard is a plant that was introduced into North America for medicinal purposes and for food back in the 1800s. It has since spread through forests across the United States and it’s a big problem.
GRABER: So Sara knew all about invasives, and she knew that some invasives like garlic mustard were also pretty tasty. But when she heard about using our appetite as a tool to manage species, she was pretty skeptical.
KUEBBING: And I think one reason I approached it with skepticism, was that it wasn’t a tool that managers were actually talking about or actually using at that time, or at least in my experience.
TWILLEY: It wasn’t that Sara thought you couldn’t eat invasives. Like we said, she already had.
KUEBBING: But then thinking about taking consumption and moving it to an actual effective management strategy raised some red flags to me from the beginning. Probably just that it was a new tool that people weren’t using. And so why weren’t they using it? There might be something not great about it.
GRABER: So we have to take a step back here—we’ve been discussing this idea Joe had that eating invasives might help eradicate them. But Joe and Sara and lots of other conservation biologists and people working in land management around the world had been trying to control invasive species for a couple decades already, and they had come up with some solutions.
TWILLEY: Joe and Sara agree that the most effective way to fight invasives is to just not bring them in in the first place
ROMAN: What we really want to do is just prevent any new species from coming in. Prevention is easier than trying to mitigate it once they’re here.
GRABER: So far, so logical. But it’s not quite as easy to implement as it sounds. It’s expensive and a lot of work.
TWILLEY: Countries that invest in this, like Australia—they spend a lot of money on border biosecurity, and it makes trade significantly more expensive and slow. And so a lot of countries decide they don’t really want to invest in that.
KUEBBING: Especially in the United States. So there’s not a lot of will, at least at this point, to create policies that would thoughtfully control the introduction of non-native species.
GRABER: So that’s a problem. At least in the US, we aren’t doing enough to prevent future invasions that could be really destructive. The Trump administration has actually been cutting funding in this area.
TWILLEY: But meanwhile, like we said, there are plenty of invasives that are already here and they’re the stuff of ecologists’ and farmers’ nightmares. So what tools do we have to fight them?
GRABER: Basically, the main tools are physical and chemical removal—so for animals, it’d be hunting and poison baits—
KUEBBING: If we think about plants, you could could do that by going in and using some sort of chemical or herbicide that’s targeted to kill the invasive. We could think about going in and hand pulling or cutting out the invasive.
TWILLEY: This sounds like a lot of work and it is. But if the invasive hasn’t spread very far, or you’re just focusing on a small area, like a national park, then it’s worth a try.
GRABER: These tools have been especially successful on islands, basically because they’re small and contained. Remember those horribly invasive rats that have been totally destructive on islands around the world?
TWILLEY: Some islands have focused a lot of effort on eradicating these rats. They’ve used helicopters to spread poisoned bait over the entire island. They’ve used specially trained dogs to traipse across every square inch of the island in search of rats. They’ve set up networks of monitoring devices to detect rat burrows and nests.
GRABER: In South Georgia, which is a small island the size of Rhode Island, they undertook a huge rat eradication effort. It took almost a decade and it cost more than 13 million dollars. But it worked. In 2018, they declared themselves rat free.
KUEBBING: And there’s been lots of success stories of eradicating rats and other small rodents on some of these islands, including places like Santa Cruz Island or the Channel Islands off the coast of Southern California. And many Pacific islands as well.
GRABER: So yeah, there have been some successes getting rid of or at least controlling invasive species on islands or in national parks. But those are relatively small areas.
KUEBBING: The point where it becomes tricky is like, let’s say you have an an invasive plant or an invasive animal that is found everywhere east of the Mississippi in the United States. Controlling that population at that landscape scale is very challenging.
GRABER: It’s really really hard to eradicate invasives once they’ve become widespread, but one tool that scientists use is called bio-control.
KUEBBING: And so the idea behind bio-control is, well, why don’t we just bring over some of those predators or pathogens then from the native range of the species
TWILLEY: This sounds so logical and so smart, what could possibly go wrong?
KUEBBING: One of the reasons why it’s very contentious is because it can backfire, because early, back in the day, there wasn’t much thought about the introduction of bio-control agents. And so people would just say, what eats the cane beetle? And they would say, oh, the cane toad, let’s bring it in.
GRABER: The cane toad. This is quite a story. In the early 1900s, Australia was growing sugar. But they had a native beetle that ate the sugar, called the cane beetle. And so, as Sara said, some folks there thought it’d be a great idea to bring in cane toads to eat the cane beetles. These toads are native to South and Central America and had long been used to eat pests in sugar plantations. So in 1935, Australians first introduced a couple hundred cane toads into the sugar plantations of northern Australia, then they introduced a few more.
TWILLEY: But cane toads can breed year round and they can lay up to 30,000 eggs at a time, Compare that to the native frogs which only lay a couple thousand eggs at a time. Surprise, surprise, the cane toads quickly took over the entire state of Queensland and started expanding into the Northern Territories. Cane toads are also super poisonous—they ooze a toxin through their skin when they’re upset—and so lots of things that like to eat frogs like native birds and snakes would eat these cane toads and die. And the final straw? The toads didn’t even make a dent in the cane beetle population!
GRABER: So I first heard about cane toads way back in high school—I can’t remember why or in what class, but we watched a documentary about cane toads. This was a while ago—well, the documentary came out in 1988—but it was so memorable that I can still picture a plague of super ugly huge toads taking over the Australian countryside and terrorizing anything that tried to eat them.
DOCUMENTARY VOICE 1: One male, one female, is more than sufficient to populate the entire top end end.
DOCUMENTARY VOICE 2: The best thing to get rid of them is to get a big stick and hit them with it.
DOCUMENTARY VOICE 3: When driving in the car, I have no hesitation of running over them whatsoever.
KUEBBING: I will say bio-control and the introduction of bio-control agents is approached a lot more thoughtfully now because of some of these wild disasters in introducing bio-control agents. Where we do things like we check to make sure before we release something like, hey, what’s the likelihood that this is going to spread and be able to persist? But I think bio-control sort of writ large is one of those management options that there’s a lot of skepticism about that we can predict every potential facet of what could possibly go wrong. And so there’s some people who would say it’s not a viable option, and some people who would say it’s our only option.
TWILLEY: One of the issues with introducing a new predator as a form of bio-control is that it might eat other things too. But ,you know what? Humans are also introduced predators! So yeah—back to Joe and Bun’s breakthrough—we could be the bio-control.
GRABER: We could theoretically be much more targeted in our appetite, we could be precision predators.
TWILLEY: With no unwanted side effects!
GRABER: Nicky and I wanted to try this out ourselves, so we joined Bun Lai in the fields around his home in Connecticut.
TWILLEY: For some foraging with a twist.
LAI: Yeah, I mean, look, you have mustard garlic over there, which is an invasive species and mustard garlic releases a chemical around it. So that that makes it more difficult for a native species to do well. Also, mustard garlic can still grow with minimal sun. So it’s incredibly resilient. This is, right over here, it’s—we have autumn olive. Which is an invasive species. It’s one of the tastiest fruits you’ll ever have too.
TWILLEY: So pretty.
GRABER: They’re these tiny little jewel like things.
LAI: Oh, yeah.
TWILLEY: What do you do with this? How do you—I mean other than snarf it like right now.
LAI: Well, we make desserts out of autumn olive and liquors.
GRABER: Must be so good as a liquor.
GRABER: Bun grabbed some garlic mustard, as well as a bunch of other greens growing in the field, and he made us a wild salad—with vinegar that was infused with Japanese knotweed.
LAI: I’m psyched to have a salad. That’s really good. I could have done a better job drying it off, but that’s okay.
GRABER: We will not grade you down for a little extra water content on the leaves. I think we’re good.
TWILLEY: Hydration is important.
GRABER: Oh wow.
TWILLEY: Hot damn.
LAI: Hot damn is right.
TWILLEY: Once Bun started cooking invasives for us, he could not stop. He made us jellyfish, which was crunchy and refreshing.
GRABER: And then he prepared these gorgeous bites of sushi with a slice of something dark red that was seared and sprinkled with a touch of green. It looked like slices of lightly seared tuna. We of course had no idea what it was.
TWILLEY: Ooh… Is it? Mmm.
GRABER: It’s very delicate.
TWILLEY: Yeah. Initially my thought was that it was gonna be some kind of like organ. But it’s so delicate that I’m like, it’s not funky the way.
GRABER: No. And not gamey. So I’m ruling out—unless it’s something small that I don’t know about. Yeah. I don’t know what it is.
TWILLEY: Like a test.
GRABER: I know. I think we’re failing this test.
LAI: You’re actually not failing the test. I’m very, very impressed. I mean, the first one you got. You know, that was jellyfish. And you just said organ. It is an organ meat. That’s wild boar heart that you’re eating.
TWILLEY: Wild boar, or feral pigs as they’re also known, are one of the most destructive invasive species in the United States. The majority are in Texas, where they cause $400 million worth of damage each year. But there are millions of them, spread across 39 states, eating other species’ food, rooting up crops with their snouts, and transmitting diseases.
GRABER: They do happen to be very tasty, too, though they learn how to evade traps and hunters. Like many destructive invasive species, they’ve been incredibly difficult to get rid of. So we were feeling pretty virtuous eating some wild boar heart as sushi.
TWILLEY: But are humans really the perfect precision predator when it comes to invasive species bio-control? Can we eat our way out of this problem?
ROMAN: When I first started out on this, people would say, well, is it really going to have an impact? You know, there are millions of these organisms in a coastline. How are just taking a few out of the ocean going to have any impact at all? Well, in Bonaire, in the island in the Caribbean, they actually promoted the harvest of lionfish.
GRABER: Lionfish are pretty cool looking, they’re stripey orange-y red fish with long spiky looking fins like a mane, like a lion.
ROMAN: So native to the Indo-Pacific, brought to the Atlantic and escaped around the time of a hurricane in Florida in the 1980s, and now has reached from North Carolina all the way down to Brazil. And many of the native grasses and groupers in those areas have disappeared when the lionfish has come in. It’s a voracious predator. It doesn’t have any what we would call natural enemies.
TWILLEY: Lionfish eat so many native fish that they can actually develop obesity problems. They eat somewhere between 75 and 90 percent of all other fish on the reef.
GRABER: But they do also taste good.
ROMAN: It’s a good white firm, meat. So what most people like—oh, you know, tastes like grouper or something like that. So it’s a familiar flavor, and very abundant.
GRABER: And so some governments in the Caribbean promoted going spearfishing for lionfish.
ROMAN: And they found in areas where they were fished that populations got more much smaller than areas where they were un-fished. One might say, well, duh, right? Of course, that is. But when you’re doing science, you have to really look at that. Right? You have to measure the impacts of these policy. So we see that fishing lionfish can reduce the numbers. And then even better, a study in the Bahamas showed that as the populations declined, native species started to come back. So we’ve got this connection. And the lionfish really helps tell the story about how eating invasive can work.
TWILLEY: So lionfish has become the poster child for eating invasives. And there’s even data to back it up.
GRABER: Sounds great! But actually not everybody is on board with eating invasives as a management tool. Sara told us she was originally skeptical when she first heard about the idea in grad school—and she’s still skeptical today.
KUEBBING: Because if I just want to make money off of lionfish, what’s going to stop me from going to the reef that’s infested with lionfish and moving lionfish from that reef to my reef, where I can then just start harvesting lionfish and selling it on the market?
TWILLEY: The problem is, if people start to like eating lionfish, then economics come into play. If you’re making money off lionfish, why would you want to eradicate it? And if you associate lionfish with Caribbean cuisine, and it becomes part of your culture, same thing again—you might not be motivated to wipe it out.
GRABER: Neither of those have happened yet, but it’s still early days. Bonaire has only had this program going for the past decade.
KUEBBING: I don’t know if that sounds like far fetched to people and especially people who are doing these efforts because they care so much about the environment or the ecosystem that they are working so hard to protect. But we’ve seen it happen actually with multiple invasive species.
GRABER: Such as the wild boar in Hawaii. It’s not native to the island, it’s just as destructive there as it is everywhere else, but it’s become an important part of Hawaiian cuisine. And so there’s less of an appetite to get rid of it.
TWILLEY: Or take Nile Perch. This was a fish that was introduced into Lake Victoria in Africa, it caused the native fish to nearly go extinct, and so local fisherman were encouraged to start harvesting it.
ROMAN: Nile perch has been harvested very hard and populations are down. And that might have a positive impact on the native species. But, you know, here’s the honest thing. The people that have been relying on harvesting these invasive could get hit by that, as those populations go down.
GRABER: But that’s not the only concern about a campaign to eat invasives.
KUEBBING: For plants in particular, which is something I think about a little bit more than invasive animals, there’s a really large risk of just spreading plants unintentionally as we harvest them.
TWILLEY: For example, if you harvest knotweed stems to make Bun’s delicious knotweed vinegar, you might drop some of those stems on your way back to the kitchen. But those stems are still very much alive. Which is why the UK government treats them like low level nuclear waste!
KUEBBING: If you drop them, if you throw them into your compost, if you’re not really, really careful with them, then you could potentially accidentally spread those plant species to other areas.
ROMAN: So that is a legitimate concern and one that requires education. And for the most part, you know, there are laws preventing the movement of these species.
GRABER: Which is good thing. but Sara points out that on the flip side, those laws also reduces the scale of the potential market for foods made out of these species.
KUEBBING: And so it means that if you wanted to create a garlic mustard pesto factory or a Japanese knot weed processing facility, you aren’t allowed to transport those species in a lot of states.
TWILLEY: Which makes it difficult to grow your business. And this question of scale is important because if we want to eradicate an invasive species we have to eat enough of it to make a difference. And that percentage varies by species.
GRABER: For lionfish, estimates are that fishermen would have to remove about 20 percent of the population to reduce the numbers and let local native fish rebound.
KUEBBING: For wild boar there’s larger estimates depending on where they are, but it’s roughly about 50 percent of a boar population. You would have to remove 50 percent of the individuals before you would start seeing population decline.
TWILLEY: And even though there are countless reality TV shows about hunting wild pigs from helicopters with machine guns, those hunters kill nowhere near that many—like not even close.
GRABER: It also can make a difference which members of the species you take you take out.
TWILLEY: Like with the American bullfrog. This is native to the eastern US, but invasive in the western states.
KUEBBING: And it was French emigrants that wanted to eat frog legs, but they ate all the native frogs. They didn’t have any frog legs left, so they started importing American bullfrogs from the eastern United States for food.
TWILLEY: And they quickly became invasive. Meanwhile, the French became Americanized and stopped eating as many frog legs.
GRABER: But in theory we could start eating those frogs again, right?
KUEBBING: So the most effective way to reduce bullfrog populations is by removing juveniles from the population. But eating invasives, eating bullfrogs, you’re going to want to remove the largest males from the population because they’re going to have the best frog legs to eat.
TWILLEY: But this accidentally makes things worse, because those male bullfrogs with the juicy thighs, they eat bullfrog tadpoles
KUEBBING: And so they’re actually performing this sort of internal bio-control on the population size. So if you start removing the large male bullfrogs, you actually see an increase in population growth instead of a decrease.
TWILLEY: Sara thinks that given all these issues, she personally is doubtful that eating invasives could ever really work, in the sense of truly eradicating these invasive species.
KUEBBING: I mean, I still am a fan of making garlic mustard pesto. And I think that if we use it at a local level where we can sort of ensure that that motivation is for the reduction in the species—and especially as an educational tool for just getting the general public to think about sort of natural ecosystems and what’s there and what other species other than humans are doing in the areas that, you know, around us—I think it can be really effective in that way.
GRABER: Joe agrees, he thinks his Eat the Invaders website and campaign is a really important educational tool.
ROMAN: I just want people to know about invasive species more and know that something can be done about it. I also just want people to get outside.
TWILLEY: Outside, exploring and learning about the plants and animals around them. As well as eating new and delicious things.
GRABER: Joe thinks that if we’re not eating invasives, we’re missing out.
ROMAN: So this is a way you can go on the web site and, you know, find out burdock’s been growing in my backyard for years. I didn’t know that I could cook that up as a root vegetable. Or day lilies, which are all over New England. And for me, they’re taste of summer, they’re really amazing. It’s kind of like asparagus. And who knew? You know, I didn’t know that until I started to put this website together and reach out to neighbors and to chefs around the country to get some ideas for new ingredients. So it’s really celebrating this diversity while hopefully reducing some of the impact.
GRABER: Still, Joe does think that we humans can eat enough of some invasive species to control their impact. It can be one of the many tools managers use. We can be a form of bio-control.
ROMAN: So for many of these species, we’re probably going to need a combination of approaches. The truth is, of course, that it’s unlikely we’re going to eat these to complete extinction. But reducing the numbers is absolutely, absolutely essential.
TWILLEY: Ultimately, Joe says, we just don’t know—maybe, for some invasive species, eating them really is going to be the way to go. Lionfish is the only invasive where eating it has really been implemented as a policy and then studied scientifically. So we don’t have the data we need to know if eating other invasives would work equally well.
ROMAN: You know, it’s only been ten years or so that we’ve been discussing this twenty tops. So there the research is just emerging.
GRABER: To be honest, after weighing all the evidence, Nicky and I are still a little skeptical, like Sara. It just seems that once there’s something in it for someone—once people get really into shooting wild boars in Texas or tracking Burmese pythons in the Everglades, or maybe eating lionfish or daylillies, it could be easy for industries to build up that would then be hard to get rid of. We’d love to be proven wrong!
TWILLEY: But getting outdoors and understanding which species are native and which are not, like Joe wants, and maybe helping tip the balance in your local environment—that’s something we’re all about. And if eating more seared wild boar sushi could make difference—I mean, that’d be great.
LAI: We have to change the way we eat anyway. We all know that, right? Especially in the food world. We all know that. This is some of the most exciting food that you can possibly eat.
TWILLEY: Thanks this episode to Bun Lai, chef of Miya’s Sushi in New Haven, Connecticut. If you want to try his amazing cooking—and believe us, you do!—you only have a year to get yourself there. At the end of 2020, Miya’s will be closing its doors and Bun will be moving on to new projects.
GRABER: Thanks also to Sara Kuebbing and to Joe Roman, we have links to their research on our website, gastropod.com.
TWILLEY: If you liked the rainbow trout story, you should read the excellent book it comes from, An Entirely Synthetic Fish, by Anders Halverson. We’ve got a link to that too, on gastropod.com.
GRABER: We’ve started to see photos pop up of you listeners modeling our brand new merch, and we’d love to see more! If you take photos of our shirts and beanies and water bottles in the wild, tag us on whatever social media you use!