Chicago’s Looming Asian Carp Problem—What You Should Know

CARPOCALYPSE NOW: Even if you’ve never been pummeled by agitated Asian carp, these fish represent a major threat. Preventing them from entering Lake Michigan could cost taxpayers a bundle—and, depending on whom you ask, flood your basement and taint your tap water too. Here’s what you need to know.

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Jeanne Gang Q&ASuperstar architect and MacArthur Fellow Jeanne Gang on a potential solution to the Asian carp problem »

PLUS: Hear Gang talk about her visionary plan for the Chicago River at a panel (led by Chicago editor Geoffrey Johnson) at the Peggy Notebaert Nature Museum (2430 N. Cannon Dr.; 773-755-5100) on December 7 at 7 p.m. For more information, go to

One of the first local leaders to recognize that something needed to be done was Mayor Richard M. Daley. In May 2003, he and the U.S. Fish and Wildlife Service convened the two-day Aquatic Invasive Species Summit in Chicago. The carp were about 55 miles from Lake Michigan.

As luck would have it, just the year before, the Army Corps of Engineers had completed an electric barrier on the canal near Romeoville. Its original purpose was to repel yet another finned menace: the mollusk-munching round goby, a Eurasian native, which was moving south from the Great Lakes. (The electric barrier functions like an invisible dog fence: creatures approaching it receive a shock that, theoretically, keeps them from advancing.) Unfortunately, by the time the barrier was up and running, the goby had already slipped by. But at least the barrier could stop the carp from going north, right?

Wrong, concluded the 60-plus experts who had traveled from around the world to attend Daley’s conference. They worried that the barrier wasn’t reliable enough to keep the carp out. There was, the attendees concluded in a postconference report, only one “essential” solution: “Completely separate the waters of the Great Lakes and Mississippi River basins by creating a physical or other type of barrier in the Chicago Canal System.” Without such a move, the experts foresaw “irreversible damage to these remarkable ecosystems.”

Amid corporate and government fears about the economic impact—an estimated $16 billion in cargo annually travels through the Chicago Area Waterway System—not much happened. The Illinois DNR did what it could—for example, hiring fishermen to catch carp in the Illinois River. Last summer, the DNR hauled in 240 tons of carp, which was turned into fertilizer; commercial fishermen caught tons more, most of which were shipped to China under an agreement signed in July 2010 by Governor Pat “If You Can’t Beat ’Em, Eat ’Em” Quinn. But that wasn’t enough to quell the threat. (Mayor Rahm Emanuel declined to comment for this article.)

Rather than rethinking electric barriers in the wake of the experts’ warnings, the Corps of Engineers kept building more. There are now three on a 1,150-foot-long span of the canal, all near Romeoville, all designed, built, evaluated, and maintained by the corps at a cost thus far to taxpayers of about $75.4 million.

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In the fall of 2009, David Lodge made an unsettling discovery. The director of the Environmental Change Initiative at the University of Notre Dame, Lodge had been hired by the corps to help assess the carp threat. He soon realized that the corps did not seem to know exactly how far toward Lake Michigan the fish had traveled. “If you don’t know where they are, you can’t fight them,” he says. “It occurred to us that, rather than capture the fish [as the corps had been doing], maybe we could figure out where they were using indirect genetic means.”

With his colleagues, Lodge began collecting water samples from the canal and testing for environmental DNA, or eDNA, cellular material the carp had left behind. “We did not expect to see evidence of the carp north of the electric barrier,” Lodge remembers. “We were astonished and very disappointed to find it there.”

In November 2009, state and federal officials announced that eDNA evidence of the Asian carp had been found on the Calumet River near the T. J. O’Brien Lock and Dam, more than 20 miles above the barrier (see map, page 94). (In addition to that lock, water from the canal passes into Lake Michigan via four sources: the Wilmette Pumping Station; Chicago’s downtown locks, officially known as the Chicago River Controlling Works; the Indiana Harbor and Canal; and the Burns Waterway Harbor in Indiana.)

To Henry Henderson, Midwest program director for the NRDC, discovery of carp eDNA past the electric barriers is proof that “the barriers don’t work.” Lodge agrees. Because DNA decomposes quickly, he rules out the possibility that the eDNA arrived in the river after passing through the digestive system of a bird or human who had consumed the carp. Other scenarios seem equally unlikely. “All the evidence that exists points to the most plausible explanation for the positive DNA findings,” Lodge says. “There are Asian carp above the barrier.”

Don’t tell that to John Goss, President Obama’s so-called carp czar (he heads the Asian Carp Regional Coordinating Committee, which comprises 21 local, state, and federal agencies). “Right now, there’s a lot of uncertainty about what traces of eDNA mean,” says Goss, who formerly worked at the Indiana Wildlife Federation. “We don’t know if it’s evidence of a live or a dead fish or if it comes from fish scales or from a barge [traveling in the Chicago canal]. We need further research.” He adds: “All evidence shows that we are succeeding in keeping Asian carp out of the Great Lakes.”

The Illinois DNR, for its part, took Lodge’s news very seriously. Within days, its biologists poured 2,200 gallons of the fish toxin Rotenone into a six-mile stretch of the canal below the barriers. The operation yielded between 30,000 and 40,000 dead or surfaced fish; only one of them was an Asian carp, and it was found five miles below the barriers. A month later, commercial fishermen hired to search for carp above the barriers netted a three-foot bighead in Lake Calumet—a worrisome development, especially since officials couldn’t say how it got there. Over the next 11 days, fishermen deployed ten miles of nets in Lake Calumet and captured more than 15,000 fish. None of them were an Asian carp.



3 years ago
Posted by Great Lakes Fisherman

Your article brings to light some good points regarding the Asian Carp issue but misses the boat in a couple of areas.

The University of Illinois has been conducting regular surveys of fish populations in the Illinois River. Those surveys have shown that, even in areas heavily populated by Asian Carp, there has been no reduction of sport or rough fish populations. In short, Asian Carp have not displaced native species in Illinois' rivers.

A recent published study has shown the electric barriers in their present configuration are 100% effective in stopping live carp of all sizes. Furthermore Asian Carp are found in isolated lakes all over the Midwest indicating that natural physical barriers or the man made barriers proposed by the Natural Resources Defense Council are neither an effective or permanent solution for stopping the movement of invasive species. The truth is that the electric barriers would be just as effective as physical barriers in stopping Asian Carp and would be far less costly than severing Chicago's waterways and increasing the likelihood of flooding and polluting southern Lake Michigan.

After nearly three years of electro-fishing, poisoning, and netting only one Asian Carp of questionable origin has been found above the electric barriers. What we know now is that, while eDNA testing may work well in the laboratory, it has little relevance in predicting the existence of live Asian Carp in Chicago's waterways.

Scientists who have studied Asian Carp and the Great Lakes ecology are in agreement that, even if Asian Carp could survive in the Great Lakes and reproduce in a few of their tributaries, the worst case scenario is that their presence would be felt in only a few isolated areas. None of these scientists are predicting CarpAgeddon or that Asian Carp would destroy the Great Lakes fishery or other recreational activities and, there are no published scientific studies that would support that conclusion.

Finally, the courts rejected an injunction to close Chicago's waterways for two reasons. First, the courts determined that Asian Carp posed no immediate threat to the Great Lakes. Second, the financial harm to the City of Chicago, the State of Illinois, and the industries that rely on the waterways for raw materials and finished goods would be much greater than the known economic harm Asian Carp pose to the Great Lakes region.

The sad truth is that the public debate over Asian Carp has been more about politicians in other states and special interests groups vilifying the Army Corps and the State of Illinois in order to gain political traction to serve their own agendas while ignoring both the scientific and economic realities of the issue.

3 years ago
Posted by Kevin Troy Surratt

The Illinoian tax payer should not pay a penny, these fish destroyed the Illinois river long before they got close to the great lakes, you people had plenty warning and did nothing until it got close to the rich on the lakes.

2 years ago
Posted by Meme the cat

I eat them. My dad eats them. My mom eats them. My grandpa, the guy who made the first wooden or metal airplane in China, ate them. They're yummy.
~Me (Pronounced like the month:May)

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