The One That Got Away
They’re breaking jaws. They’re spawning lawsuits. They’re pitting states against states. Now, as Asian carp invade Minnesota, they’re even worrying the president.
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The farthest north that Asian carp have been reported in North America, albeit in small numbers, is Minnesota, specifically Lake Pepin, the scenic bulge in the Mississippi River where water skiing—not a recommended activity around Asian carp—was reputedly invented.
But some scientists told me the fish could easily be as far north as the Twin Cities. No one knows for certain, as there’s little if any routine fish monitoring in the Mississippi north of Red Wing. But that’s no reason to assume the fish aren’t there, says Steven Gutreuter, a research statistician with the Upper Midwest Environmental Sciences Center in La Crosse, Wisconsin. “I would not be surprised,” he says, “if some Asian carp have already made it up to St. Anthony Falls”—swimming within sight of the Guthrie Theater.
That wouldn’t surprise Peter Sorensen either. The University of Minnesota scientist has studied carp of all kinds for about six years. “These are the only Asian carp legally in Minnesota,” he says wryly as we peer into giant, well-sealed tanks in a St. Paul building he’d prefer I not identify. Pranksters might release the carp into the wild, and “the last thing I need,” Sorensen says, “is to be known as the guy who ruined everything.”
The fish look almost innocent. They’re juveniles, no more than three inches long, used by Sorensen’s students for experiments with carp barriers and carp physiology. The mouth of an Asian carp is at the top of the head, the eyes at the bottom, the better to feed at the water’s surface. The fish look slightly out of whack, pathetic even, like they’d be bullied down at the local sandbar—like a minnow.
Which is technically what they are: the largest, most annoying members of the minnow family. Sorensen has come to admire carp, the way Holmes admired Moriarty. They learn to avoid nets. They thrive in polluted waters. They have terrific hearing, are strong swimmers, and are some of the most fecund animals on earth: Bighead females can produce more than a million eggs at a time. “They’re really impressive,” Sorensen says.
All the same, he’d prefer them dead. Asian carp are wired to spawn whenever the water rises around them—as during a flood—up to several times a year. Their populations tend to remain low after they invade new territory, until a few good, consecutive years of spawning. Then, as biologists put it, their numbers “pop” and you get something like the scenario in Havana. In the last couple of years, they’ve popped in Kansas City and on the Wabash River in central Indiana. A few good spawns in Minnesota, starting with protracted flooding this spring from all the snow in the Upper Midwest, and they could pop here any year now.
If left unchecked, Asian carp could fan out into any Minnesota river long and straight enough to suit their spawning. They could invade any lake with an outlet to such a river, including some of the best walleye fishing spots. They could permanently change the way we view our state—especially from an unprotected boat.
Sorensen doesn’t foresee us stopping them. Not because we couldn’t develop the tools (“It’s a fish, okay?” he says. “We put a man on the moon!”), but because we haven’t. And we’ve had more than 30 years to do so. Only now are Sorensen and other scientists across the country getting grants to experiment with gizmos like underwater barriers that would limit the carp’s spread, and they’re still years—and a lot more money—from implementation. “This is a four-alarm fire,” Sorensen says. “And we’ve got nothing to put it out with.” Instead, he bemoans, the state of Illinois is arguing against closing the Chicago shipping canal by vaguely suggesting that there might not be enough plankton in the Great Lakes to sustain the invading carp. “Might not?” Sorenson asks. “As a biologist, I don’t think that’s a satisfactory risk we should take.
“Think of it this way,” he says. “If your neighbor had cholera—if it was a human disease we were talking about—we wouldn’t be reacting like this. Invasive species are like a cancer on the environment. And, as we did with cancer, we need to be focused in attacking them. It would help if people looked at it that way.”
Minnesotans could be forgiven for still thinking of Asian carp as a “downriver” problem, like hurricanes, nutria rats, and voodoo. Compared to the carp’s invasion of Lake Michigan, its voyage into the upper reaches of the Mississippi River has been relatively unheralded.
For years, the fish were more or less contained by the dam crossing the Mississippi at Keokuk, Iowa, near the Missouri border. It’s a huge span, some 4,620 feet long; when it became operational, in 1913, it was second only in length to the Aswan Dam straddling the Nile in Egypt. More important, it’s tall—there’s a 38-foot difference between the pool above it and the river below—making it a formidable fish barrier. Even today, the Keokuk dam is considered the front line in the Asian-carp invasion of the Mississippi: Above it, the carp are numerous but not abundant; below it, they’re predominant, as inevitable as pigeons on a statue.
But enough carp have breached the fortress now to sustain the northward invasion, and, on a recent visit to the dam, I can see why. For one thing, there’s a lock. And although Asian carp are bothered by motor noise (thus all the jumping around boats), they’re capable of locking through when boats do. Also, there’s simply a lot of carp on the southern side of the dam.
“There’s shitloads of ’em,” a man fishing near the lock informs me. “This river is thick with ’em.” And since the carp are dead ringers for gizzard shad, a fish that anglers like this old-timer net from the river to use as catfish bait, it’s easy to accidentally net some juvenile Asian carp, throw them in a bait bucket, and never notice the difference. “I’ve seen guys fishing with ’em over there,” the old-timer tells me, pointing to the north side of the dam. When they’re done fishing, he says, they simply toss the bait fish in the water. And upstream go the carp.
Once beyond Keokuk, the carp can swim around or even over smaller dams during floods—the Corps of Engineers raises dam gates out of the water whenever the water levels above and below a dam equal out, as the dam isn’t serving any navigational purpose then (it’s said to be “out of control”), creating a clear passage. The record flooding of 2008 seems to have given the carp a big push; they’ve turned up in Iowa far west of the Mississippi, and in great numbers, like sand deposited by a wave.
If Minnesotans are largely unaware of the invasion happening right beneath their boats, it may be a result of how Asian-carp sightings are reported here. If a commercial fisherman working the river finds an Asian carp among his catch, he might or might not call the local DNR office, which might or might not care, depending on whether the fish was caught where they would expect to find it. The fisherman might or might not have kept the carp to show them. The DNR might or might not write a press release. The local newspaper might or might not publish it. In the last five years, only a handful of Asian-carp catches in Minnesota waters have made the news, giving the impression of isolated fish arrested like terrorists before they could do any harm.
To gauge how many Asian carp are actually here, I drive to Lake Pepin one fall afternoon, curious if there are already enough there to make an impression on the people living around them. I ask the employees working at the area’s largest marina, in Lake City, if they’ve seen any Asian carp. None of them say they have. Same with the men in shorts and deck shoes walking out to their sailboats. “If they were out there,” one guy says while wrenching apart the huge twin propellers of his speedboat, “I’d know it.”
But on my way out of town, I notice a handful of men standing beside a doublewide in a trailer park. They’re old-timers, greybeards—the kind of men who would notice something different in the water—and they’re cleaning fish. The oldest one is wearing a sweatshirt that just says “Fishing” on it. “Yep,” his buddy tells me. “Seen two.”
“Silver or bighead?”
“Silver. An’ uglier than heck. Jumped like crazy.”
Another guy points at the lake with the can of Natural Ice beer in his hand and says that a commercial fisherman, working the lake’s backwaters near Stockholm, Wisconsin, found a half-dozen Asian carp in his catch just that morning.
“They’re here,” he says. And as I walk away, he shouts, “Give ’em hell!”