Snakeheads: the Asian Fish That Terrified Arkansas
How a government team called Operation Mongoose tried to get rid of the invasive northern snakehead by poisoning 400 miles of Arkansas waterways.
Lee Holt, a biologist with the Arkansas Game & Fish Commission, aims his Chevy Silverado south, heading from his field office in Brinkley, Ark., out to the rice and soybean farms that surround this small Delta town. It's a hot, sticky summer day, and the A/C is thrumming inside the cab as Holt passes a Lutheran church on Highway 49 with a marquee that reads, "We Don't Serve A Wimpy God." This is the same road that he traversed a few months earlier, when he got a call from Russell Bonner's farm that changed his life and launched a sort of paranoia — and eventually an unprecedented government response — in these parts.
He let himself hope then that it was a snipe hunt; he's been on plenty of them as the concern spread. The concern comes in the form of telephone calls from amped-up Arkansans who are convinced that they've found specimens of the northern snakehead, Channa argus. The fish does not belong here. It has no local predators. It is an obligate air-breather and thus can live outside water for days. It can wriggle swiftly through the scantest smattering of water. It is a top-level predator with fearsome teeth and a carnivore's appetite. It breeds up to five times a year, producing tens of thousands of young, and as both parents protect the hatchlings, it is a prolific breeder.
Fishermen catch something that looks even vaguely like this invader, and they freak.
Callers have told Holt they caught a fish — a snakehead for sure — and threw it into the weeds, but they can tell him where it is. A woman called recently and said she was sure a fish she found was a snakehead because it "attacked" a bucket she set near it. "People just want to have a snakehead," Holt says. "They're confident, regardless of what you tell them."
The irony is, no one in his right mind wants the fish around. Even the prospect of their existence here is a relatively new phenomenon. It was April 2008 when Bonner phoned, claiming he had a snakehead. At the time, the fish was thought to be contained in the United States; none had been confirmed in Arkansas, a fish-friendly state that's home to nearly every species of freshwater game fish found in the United States. "I tried to talk him into that he had a bowfin," Holt recalls.
The rice farmer knew otherwise. He had found the fish on a dirt access road that crosses his land. A culvert had clogged in heavy rains, and it wasn't unusual to see curios float up. Bonner thought the fish a bowfin (also known as a grinnel), but it looked odd. He scooped up the live fish with a shovel and tossed it in the back of a utility truck, drove it back to his office and asked whether anyone had seen a grinnel like it before. A couple of days later, someone remembered the fish and went to dispose of it.
"Fish was still alive," Bonner recalls as he and Holt stand on the stretch of dirt road where the fish was found. "After a day and a half of laying in the back of a truck, he whacks it with a shovel and throws it off in a ditch. I get to thinking about it and talking to different people, and said, 'That might have been something we need to look at.'"
His concern was grounded; though at the time, no one in east Arkansas knew it. Since its first appearance in two Maryland ponds in 2002, northern snakeheads had popped up variously in California, New York, Virginia, Florida and North Carolina, always to outsized reaction. The U.S. Fish and Wildlife Service made importation of the fish illegal under the Lacey Act in 2002. But in 2000, a fish farm south of Brinkley tried raising snakeheads, which fetch high prices in Asian fish markets. When informed that the fish could potentially constitute a menace, the owners seined the pond and cast the fish onto the bank. Nothing seemed amiss over the intervening years, though Bonner now says of the creeks around his place "used to be good fishing; then we noticed you couldn't catch any fish. 'Course, we didn't know why."
The theories as to how the fish got from the fish farm to the Bonner place, a solid mile away, is anyone's guess. If you believe in the fish's alleged powers of cross-land propulsion, one or two must have flopped their way to a nearby ditch. Maybe a pregnant female missed the seining, laid in the muck and escaped through drainage.
Either way, years passed. All was quiet. And then Holt got a gander at the fish that survived a solid day in the back of a truck.
"As soon as Russell opened the top of the bucket," Holt says, "my heart sunk down to my stomach."
Instead of being ground zero for an outbreak of invasive fish, Brinkley would prefer to be known as the home of the ivory-billed woodpecker. The majestic bird was believed to be extinct in the United States for about 50 years, until sporadic sightings and a blurry video shot in 2004 suggested to experts that a few specimens may have remained shrouded in the swamps all these decades. Ornithologists descended on the small town and traipsed into the woods looking for proof. Hopeful national media followed the redemptive storyline: Maybe we didn't slaughter all these birds after all. The town transformed into a tourist trap for the woodpecker set. Years later, with no further evidence of the bird's existence, the billboards that flank Brinkley on both sides of the Interstate advertising the town as the bird's home seem ever sadder, ever more desperate.
The story of the bird runs perpendicular to that of the nefarious fish now infesting the backwaters around this Delta town. The woodpecker died because people prized its beautiful head, and because they drained swamps and felled forests to clear the ground for rice and soybeans. In so doing, they made the land just that much more hospitable to the snakehead, whose native Asian habitat is, like Arkansas, a land suited to growing rice with its concomitant irrigation systems and watery flats. (You have to wonder whether anyone has attempted a Chinese translation of a bumper sticker common here: "Have a Rice Day.")
Still, it was hardly ordained that the fish would find its way to these parts, let alone find purchase here. The story of the snakehead's spread in the U.S. and to Arkansas illustrates the seeming inevitability of unnatural migrations in a world once again flat. The northern snakehead is native to Russia, China and Korea and came to North America as an aquarium-bound pet (though one that potentially will devour its tankmates) and as a prized main course, often steamed with vegetables, pan-fried or used to anchor a whole-fish soup. (The fish's physical durability makes it a relatively easy animal to transport live.) Here, it has the potential to join a roster of past invasives that have so thrived that they could be mistaken for natives: rats, hogs, kudzu, Japanese honeysuckle, goldfish, Rosa multiflora, burning bush, pythons, Brazilian pepper plants, the emerald ash borer, zebra mussels, iguanas and white mulberry. The Asian carp, which now is threatening Lake Michigan, also had a breakout from Arkansas aquaculture. Invasives compete with native species for food, spread disease and often lead to reduced biodiversity.
Species enter and fade from foreign ecosystems all the time; considering the arduous task that is evolution, it's no surprise that most nonnatives entering a given environment will not prosper. But the ones that do survive and thrive share certain traits. Foremost among those, according to Chris Bright, author of Life Out of Bounds: Bioinvasion in a Borderless World and president of the nonprofit Earth Sangha, which seeks to restore native forests, is a tendency not to rely too heavily on any other single species. "They tend to be generalists, whether they're a plant or an animal," he says. That is, they don't require a symbiosis to feed or breed. They adjust to variations in climate. They multiply with ease. A plant specialist, Bright groups these qualities under the term "weediness."
The northern snakehead has displayed all the tenacity of a weed in its American infestations. As a survivor, it's concerning; as an omnivore, it's potentially a threat to nearly every fish in an aquatic ecosystem; as a prolific breeder, it's the total package. In his 2004 U.S. Fish and Wildlife study of snakeheads, fishery biologist Walter Courtenay cites snakeheads' threat to native fish (and thus, to the economy in many places), and especially the threat to endangered fish and crustaceans, as among the fish's greatest potential impacts. "Depending on the habitat," he wrote, "snakeheads have the potential to detrimentally alter aquatic communities." He concluded that the fish's probability of establishment and the consequences of that establishment were "high." The fish's hideous countenance and creepy air-breathing, while not themselves dangerous, only make it that much easier to revile.
Maryland game officials addressed the infestations there by poisoning ponds with rotenone, a piscicide derived from the stem of a Mexican vegetable and considered relatively harmless to people. In those closed waters, the fish was eradicated. Two years later, though, it appeared in the Potomac River, a vastly more complex system.
Virginia biologists John Odenkirk and Steve Owens have monitored the fish in the Potomac for years. Dogue Creek, a Potomac tributary they define as the epicenter of the outbreak, has been home to 80 percent of the 505 snakeheads captured (mostly by stunning them with an electric charge). In a 2007 journal article in Transactions of the American Fisheries Society, they wrote that the maximum size of the snakeheads surveyed increased each year, suggesting a maturing population. Among the identified remains of other fish in the snakeheads' guts, the fifth most common was the goldfish — like the snakehead, a "naturally reproducing exotic species," the authors noted.
Media coverage of the fish peaked in 2004 and 2005, Odenkirk and Owens wrote. Anglers held snakehead "rodeos," and stores offered bounties for the beasts. A 2005 Virginia law made it legal to keep creeled northern snakeheads so long as fishermen had caught the fish legally, killed it and notified authorities. Catch rates, both by anglers and by scientists, continued to rise.
"Once we recognized that we had natural reproduction, it was not even a consideration that we could eradicate them," Odenkirk says in an interview. "Biology and physics are not going to allow for the eradication of that fish from a place where you have mile-wide channels in places."
Apparently, snakeheads have the potential to get cozy nearly anywhere in North America. When a team of scientists modeled the potential distribution of the northern snakehead for the Canadian Journal of Fisheries and Aquatic Sciences, they found that it could range from deep in Mexico to all but a few hot crannies of the continental United States, across Canada and up into the Aleutian Islands. (The northern snakehead prefers air temperatures between 41 and 64 degrees and tolerates almost 200 days of frost a year.)
Past initiatives to battle the snakehead were successful only in containing the creature to a relatively static body of water such as a lake. For all their adaptability, snakeheads tend to prefer stagnant to flowing water. "The nastiest water you can think that a fish would be in, that's where they'll be," is how Holt puts it. But in Arkansas, if the fish does migrate, either by will or flood or human carrier, the direst concerns border on an invasive-species disaster. Save for a small bottleneck, there's no natural barrier from the infested watershed of Piney Creek to Big Creek. Big Creek runs into the White River, a trout fishing mecca known for its pristine waters. From that point, the White runs south through the White River National Wildlife Refuge and, about a hundred miles north of the Louisiana border, connects to the Mississippi River.
From there, it could go almost anywhere in the eastern U.S.
No one really knows whether the snakehead could spread through these routes, whether it would be inclined to and whether it would thrive in doing so. But biologists aren't keen to simply watch and see where the snakeheads go.
"What happens if we don't do anything?" Holt asks. "What happens 10 years from now, 15 years from now, 30 years from now? Have they impacted our sport fish population? Is it pretty much just all snakeheads over in the Delta? We don't know."
The authorities in Arkansas decided there was no point in taking chances. In the spring of 2009, they brought to bear the full force of helicopters, amphibious tanks called Marsh Masters and even spring-breaking undergrads with the goal of eradicating the snakeheads. The name was Operation Mongoose, and the method was to indiscriminately poison every gilled animal anywhere in the vicinity of a known snakehead.
The first thing that strikes you about Ginny Adams' classroom is the smell of formalin, a pungent embalming agent, the acrid scent of decay staved off. A couple of months after Operation Mongoose, the science classroom at the University of Central Arkansas — in Conway, about 90 miles west of Brinkley — is a cheery repository of dead snakeheads. Country radio plays on a stereo while students wander in and out, some handling the fish corpses wrapped in cheesecloth and stowed seemingly in every sink and cranny.
A weeklong eradication effort turned up thousands of dead snakeheads, 786 of which were toted back here for study. The most fearsome of the lot is an adult nearly 30 inches in length, a gruesome silver creature nearly as long as the ice chest that held him in a back room. But by far the more concerning fish are the silvery young, bottled up in a cafeteria-size repurposed mayonnaise jar. These are the juveniles, the 1- and 2-year-old fish that Adams tallied in astonishing numbers and that may in hindsight constitute the best justification for the expensive attempt to wipe out the snakeheads.
"The crazy thing is, even in ones not much bigger than this, we're getting eggs and sperm," Adams says. "In their native range, we're looking at second- or third-year spawning. Here, we have the potential in Arkansas to look at year-ones actually able to produce gonads."
That is, not only were these fish part of an apparent baby boom, they were sexually viable earlier than Adams had found in East Asia. Even for a fish with such a broad possible range of survival, something was clicking for it in Arkansas that Adams says is unparalleled in the literature on the fish.
Hence, Operation Mongoose.
The seeds of the operation were planted two weeks after the first snakehead turned up at the Bonner farm. On April 28, 2008, a follow-up sweep produced 90 snakeheads in a single 2.5-mile irrigation ditch, and the next day, snakeheads were found in Piney Creek. Not long afterward, the operation launched, and it was a multi-agency affair: helicopters and ATVs from Arkansas, wildlife officials from Mississippi and Tennessee, and about 20 UCA students at any given time on the ground scouting, poisoning and collecting fish.
It was a grueling week. When students spotted fish, they'd quarantine those waters with block nets, then set about cataloguing the environment: the water chemistry and depth, the stream width, the vegetation types and density. A team would hit the water with rotenone, the fish poison. Another team would return to find bodies of dead fish of all sorts, and collect the snakeheads (along with some similar species, like bowfin) for transport back to the parking lot of a motel, where students injected the fish with formalin, wrapped them in cheesecloth and packed them in coolers. Then they'd adjourn to an Italian restaurant that couldn't sell them alcohol but saw no problem with the exhausted workers bringing their own in the back door.
"Any time you get a nonnative species such as snakeheads that have the potential of gravely harming your native species, it's going to draw a lot of attention," said Ricky Campbell, the hatchery manager for the Pvt. John Allen National Fish Hatchery, a U.S. Fish and Wildlife Service facility in Tupelo, Miss. During Operation Mongoose, Campbell coordinated a Fish and Wildlife assessment team that followed a day behind the eradication teams to count the dead fish. On his first day, his assigned coordinates took him to a flooded rice field. His drop point was 1.2 miles from his pickup, he said. The only way to do his job was to walk it, through the water. "I didn't go 10 yards before I saw a cottonmouth as big around as my arm," Campbell said. That snake was the first of 17 he saw on that walk. But by the end, he was convinced of the eradication's efficacy: "It was a good kill. Critters were dead all down through there."
The agency dosed larger areas by helicopter. In all, 18,000 pounds of powdered rotenone and nearly 3,000 gallons of liquid rotenone were strewn along 400 miles of waterways across 68 square miles — an area three times the size of Manhattan. Campbell said the only operation he's been a part of with the same militaristic feel and command structure was Hurricane Katrina relief. The total price tag was around $750,000.
Considering the indiscriminate murder of the native fish, including game species, the local response was encouraging. "We're mud-covered, down in a ditch, seining," Adams says, "and these people would pull over and ask, 'Are y'all trying to get those snakeheads? Good! Get those the hell out of here!'" People who worried that the snakeheads would devour the native bass population missed the larger point, she says. Game fish can be restocked, but if the snakehead was found to wipe out smaller fish, those would be gone for good.
"A lot of people from all over the country are watching Arkansas very closely right now, because from a policy standpoint, from an action standpoint, have we done the right thing?" the professor says. "And maybe we didn't, but we had to try."
As it turned out, further study has been inconclusive on that point. For one thing, rotenone poisoning causes the fish to disgorge, making it difficult to ascertain their diets from stomach contents and therefore difficult to assess just how much of a threat they posed to other fish. And curiously, the fish found were, on average, not as heavy for their length as those pulled from the Potomac in studies there.
Adams was encouraged by the returns. Best case? The operation snuffed the snakehead problem completely. She admitted this was highly unlikely. More likely, the operation depressed snakehead numbers such that they could be contained through standard control methods like spot treatments with poison and local monitoring. "The other option is," she said, "by killing out all the natives, we opened up a huge ecological niche for the snakeheads. And [then] we see a population explosion. That's the worst-case scenario."
It's nighttime in the swamps of Louisiana. A fish the size of a sedan has just leapt onto a houseboat to attack a man who kills it with a shotgun blast to the beast's head. He cuts out the fish's heart, barbecues it and takes a defiant bite. That's when a second giant fish leaps out, eats his torso and then wriggles back into the dark water.
"It can breathe out of the water?" an onlooker yells. "How the f— can it do that?
A foxy biologist pipes up. "It must have a vestigial air lung, like Chinese snakeheads," she says. "They can live out of the water for days. They're voracious. They took over a lake in Maryland a couple of years ago, and the Wildlife and Fisheries people had to poison the whole lake. They were scared. …"
"It's a monster!" another woman cries. "It's not a fish!"
This impromptu (and astonishingly accurate) biology lesson is from Frankenfish, one of at least two snakehead-inspired B-movies that came out in 2004 (along with Snakehead Terror, another instant classic) that played upon — or perhaps preyed upon — the hysteria that marked early revelations of the fish's arrival in U.S. aquacultures. Both Odenkirk and Courtenay mentioned during interviews for this story that their views of the media had been dimmed by their experience with previous snakehead coverage; Courtenay agreed to be interviewed only via e-mail because he'd been misquoted in the past. (One myth he'd like to dispel: The fish cannot "walk" across land.) None other than National Geographic referred to the animal as "Fishzilla."
Eventually the journalism subsides, and science is left to do the durable fact-finding. After studying the fish in the Potomac for years, Odenkirk is less than sold on the threat the snakehead poses to that ecosystem. "We've cried 'the sky is falling' a few times on things like hydrilla, and hydrilla was one of the best things to happen to that river," Odenkirk said. "Some invasives haven't proven to be an ecological disaster."
The northern snakehead is, after all, a fish, not a monster, and its impact has yet to be determined. Say this for the fish: It is a marvelous survivor. It was just weeks after Operation Mongoose last year that a fisherman caught a snakehead 8 miles east of the Piney Creek drainage; the man chopped its head off and reported it to Game & Fish. "I think it was just a fluke fish," Holt said. "You have that all the time. You have manatees up in Memphis. You have bull sharks in St. Louis. Stuff like that happens."
In October, UCA students conducted another week of sampling in the areas where the fish were formerly rampant. This time, they found just eight fish in the ditches and backwaters where thousands died in the eradication. The Bonner farm, the site of the original discovery and by far the most fecund ground for the fish since, produced five snakeheads. High water due to record rains at the end of October and a generally wet winter — the third straight year that the state has seen abnormally heavy rains — have delayed further sampling. Viewed optimistically, the high water could push the fish far enough away from each other (especially when waters recede, isolating some backwaters) that spawning will be less likely.
"Going into eradication, we knew we weren't going to be 100 percent effective," Holt says 10 months after Operation Mongoose, "but we did accomplish what we were after. It bought us a little time."
That time will go to further study. The question of the snakehead's interaction with the local species, especially the biologically similar bowfin, is, in one sense, the primary question here. After all, why fear the introduction of a new, delicious, self-sustaining species if it doesn't interfere with the native flora and fauna?
Courtenay points out that the effects of nonnatives on aquatic systems with only a few species of fish (desert river environments, for example) can be fast and devastating. But in a more interwoven environment, it could take years or decades for an invasive's impact to be felt. There is, he says, "no guarantee that such an addition will, in the future, not become a dominant species in that ecosystem to the detriment of the natives." In his view, Operation Mongoose was an expensive test of whether eradication was possible. Judged on that basis alone, the effort was unsuccessful. "This was a well-intended effort that has now indicated that trying to eradicate an invasive aquatic species is the ultimate impossible dream," the biologist says. Maybe even up there with trying to wish an extinct native bird back into existence.
Further study of the fish may yield a solution more elegant than mass fish kills. Until that happens, the state is invested in local monitoring and control. Every so often, an angler pulls one out of a ditch and reports it. Mongoose did not finish off the snakeheads. "Looking back on it, it was a very, very near insurmountable task," Virginia's Odenkirk said. "The deck was stacked against them to begin with, just based on the physiology of the fish."
But an infestation, even by an accused monster, doesn't necessarily constitute calamity. By summer's end, Adams felt good enough about the results that she was able to strike an upbeat tone when she presented her findings to the Oklahoma Chapter of the American Fisheries Society. Among the surprises she relayed: The fish were found largely in areas with far less vegetation than has been characteristic of northern snakeheads elsewhere, and they were found in density similar to the bowfin, the most similar native fish.
Measurements of the fish begat a bar graph of the population distribution — weighted heavily toward young fish — that reads like fear unrealized. "This size-class structure that we observed is very similar to what they had in the Potomac River the year they had a 950 percent increase in population density," she told the conference. "Operation Mongoose occurred when we were probably right on the cusp of that sort of increase." In this stage, at least, the worst may have been averted.
One of the slides in Adams' presentation depicted a smiling, bearded student holding a knife near a filet of fish on a cutting board in the bed of a trailer. Superimposed on the photo were words Arkansans may come to live by when it comes to future snakehead control. It read, "If you can't beat 'em, eat 'em."