Invasive Species: Catchin’ Some Asian Carp

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The shirt says it all

As fish go, silver carp—one of several species that fall under the general term Asian carp—have a lot going for them. They are voracious feeders, they can grow to more than 40 lbs. and their bony bodies mean few Americans want to eat them, so they can escape the overfished fate of their more filletable cousins. But they do have one slight evolutionary drawback—silver carp respond to the sound of a motorboat’s engine by leaping out of the water. And that puts them at the mercy of hunters like Zach Nayden, who has come with his crew to the small town of Bath, Illinois, to capture some carp. As we roar with a flotilla of other boats down the Bath Chute—an 8 mile-long channel next to the Illinois River—the carp begin popping out of the water, sometimes in high, lazy pop flies, sometimes with the trajectory and velocity of a hard line drive. Nayden’s crew lean out of the boat with nets and grab the shimmering fish as they somersault in the air. This is serious work—Nayden is here for the annual Redneck Fishing Tournament (yes, that’s the name), where the boat that nets the most carp can take home hundreds of dollars. And if that’s not enough to get your heart pumping, there’s a frisson of danger—a flying adult Asian carp is a sea-to-air missile, and out here, the fish fight back. “One of these nails you, it’s like getting hit with a brick,” Nayden says as he steers the boat with one hand, a net in the other. As if on cue, one of his crew takes a carp to the kisser. “Right in the face!” Nayden exults. “That was awesome!”

OK, so the Redneck Fishing Tournament may not be the most humane, safe or sane sporting event in America. And it probably has more to do with drinking beer in an environment where no one will blink twice at your Confederate flag bikini than it does with actual fishing. But the two-day tournament held in early August has its roots in a real problem—Asian carp have invaded the Mississippi and Illinois Rivers, where they’ve crowded out native species and peppered unwary boaters with fish shrapnel. Now they’re poised to infiltrate the Great Lakes, where they could ravage the native ecosystem and disrupt a commercial and sports fishery worth billions of dollars. The situation is so serious that last month several Great Lakes state filed a federal lawsuit to force the Army Corps of Engineers to step up its anti-carp measures, and Washington may soon name a “carp czar.” “Asian carp will kill jobs and ruin our way of life,” said Michigan Attorney General Mike Cox after the lawsuit was filed. “We cannot afford more bureaucratic delays—every action needs to be taken to protect the Great Lakes.”

So how did these illegal immigrants get here? Like many invasive species, the Asian carp are an object lesson in unintended consequences. (There are two main Asian carp species invasive in the U.S.: the silver carp and the apparently smarter bigmouth carp, which don’t jump out of the water.) They were imported in the 1970s from Asia—where they’ve been cultivated in aquaculture for thousands of years—for fish farms in the southern Midwest. At some point—most likely due to flooding—they escaped into the Mississippi River, and have steadily moved upstream since. The carp thrived in their new environment—in parts of the Illinois River, which branches off the Mississippi, 9 out of every 10 fish are now Asian carp, crowding out more valuable native species. Ravenous filter feeders, Asian carp can eat as much as 20% of their body weight in plankton per day, and females can lay a million eggs at a time. Though they’re not predators, the fear is that if Asian carp established themselves in the Great Lakes and their tributary rivers, they could wipe out the bottom of the marine food chain, wrecking havoc on an already stressed ecosystem. “From everything we’ve seen in other water bodies, they basically take over,” says David Ullrich, executive director of the Great Lakes and St. Lawrence Cities Initiative. “There’s tremendous fear of what they could do.”

Tools of the carp catching trade

If the Asian carp do take over, it would be through the Chicago Sanitary and Ship Canal, the only connection between the Mississippi river system and the Great Lakes. The canal is the Thermopylae in the war against the carp, and the Army Corps of Engineers has done its best to close off the pass, building electrical barriers through the canal about 30 miles downstream from Chicago. The barriers send a small jolt of juice across the water, enough to repel any approaching carp while allowing ships and sewage—the canal carries Chicago’s treated waste—free passage. The Corps is also looking into further backup measures—like another barrier that uses acoustics and bubbles to further dissuade incoming carp—and longer-term strategies, but they believe they can defend the Great Lakes bow. “I feel confident that working together with other agencies we can do this,” says Colonel Vincent Quarles, the commander of the Corps’ Chicago district and a veteran of the Iraq conflict—so he should know about waging war.

But some environmentalists and state politicians worry that the Corps’ barrier system is less impregnable Spartan defense than ecological Maginot Line. Chances are some Asian carp are already in the Great Lakes—researchers led by David Lodge at Notre Dame have found carp DNA in Lake Michigan, and earlier this summer a fisherman caught a live bighead carp in Lake Calumet in Chicago, past the electrical barrier. That doesn’t mean the barrier isn’t working—the Illinois Department of Natural Resources theorized that the bighead carp might have been introduced directly into Lake Calumet by a person—though some researchers noted that the data was far too limited to be sure, and that it might have spent time in the Illinois River. But the barriers were shut down for a short period of time during 2008, which might have allowed carp to pass through. And periods of flooding can link the canal and the nearby Des Plaines river, giving Asian carp a chance to bypass the barriers altogether. Critics argue that the fact that virtually no live carp have been found past the barriers indicates that they’re working, but Asian carp are hard to catch. “If there were a thousand fish in Lake Michigan, we might have no idea for sure for a long time,” says Duane Chapman, a biologist with the U.S. Geological Survey who studies Asian carp. “It’s unlikely that the fish are currently established but we can’t rule out that possibility.”

Remains of the carp

For those who really fear the Asian carp, even that possibility is enough to call for more drastic measures, including the closing the locks on the Chicago canal and essentially sealing off the Mississippi and the Great Lakes. Business interests in Illinois have fought hard against that course of action, arguing that the economic damage due to lost shipping would far exceed the cost of the carp, even if they did slip past the barrier. (A study by DePaul University estimated the cost to shipping alone of closing the canal locks would be $4.7 billion over the next 20 years.) “A single barge on the canal carries 80 truckloads of material that would instead have to be on our roads,” says Jim Farrell, executive director of infrastructure at the Illinois Chamber of Commerce. “It’s irresponsible.”

The lawsuit filed by Cox and other state attorney generals isn’t likely to succeed—the Supreme Court denied similar attempts earlier this year. But even with the Obama Administration spending nearly $80 million on Asian carp control, more may need to be done. Asian carp are hardly the only invasive species threatening the Great Lakes. There are over 180 other alien species in the system—including zebra mussels, round gobys and sea lampreys—that can go back and forth between the Mississippi and the lakes. Beyond beefing up surveillance of international shipping—many invasives hitch a ride inside the

ballast water of container ships—separation is the only sure way to prevent the carp and other invasives from making a vacation home in the Great Lakes. “How much longer will we battle this stupid thing when we could get a much better solution by instituting a physical barrier?” says Nicholas Schroeck, executive director of the Great Lakes Environmental Law Center. “We can make this work.”

I have to admit, though, as I’m tooling around the river at the Redneck Fishing Tournament, having Asian carp in your lake seems less ecological disaster than totally awesome. It’s all like a real-life version of Whacking Day from The Simpsons, only instead of snakes, we’re whacking flying fish, and instead of Barry White singing, there’s redneck karaoke. Somehow this is all legal—or at least most of it. I learn while I’m there that the Illinois Department of Natural Resources will allow you to drive a boat around at high speed with crew hanging out the side trying to catch flying Asian carp with a net; they’ll let you do this without a lifejacket; they’ll let you do this while drinking beer and wearing a Viking costume—but if you hang your feet off the end of the boat, it’s a $75 fine. These are the mysteries of the Original Redneck Fishing Tournament.

Personally, I don’t thinking carping and drinking should mix. Halfway through our hunting trip, as we’re speeding down the side of the Bath Chute, Nayden hits an underwater school of carp and suddenly the sky is filled with fish, like shrapnel from a grenade burst. They’re coming at us from all directions, writhing on the floor of the boat, bouncing off the windshield. I turn my head and a carp hits me square in the stomach, knocking the wind out of me. I’m carped—I’m left with blood, scales, slime and one now-unusable shirt. The offending silver carp flops on the floor of the boat, still pulsing to the sound of the motor’s roar. I understand. OK, carp—now it’s war.