Nothing was normal about this fishing expedition. The water—not a natural pond or stream. The temperature—well below freezing. We weren’t allowed on the fishing boats, our guides told us, because it wasn’t safe today. And the fishermen we watched were hoping not to catch the very fish we had all come here for—fish that, by the way, will neither strike at a worm, no matter how smelly, nor follow a lure, however realistic. Fish whose peculiar habits have created quite a problem—and whose same habits may offer hope for solutions.

February’s “carp corral” was an effort to see how far the contagion had spread, a test of whether radical surgery might be justified. Three olive green launches not much bigger than rowboats were “electrofishing” a stretch of the canal on the southern edge of Cicero, nine miles from the lake. Live lines dangling from their bows created electric currents used like cattle prods to herd fish toward underwater seines. Men with long-handled nets stood on deck snaring any stunned fish that floated to the surface. The fate of water people of various trades depended on what emerged from the murky water (I myself depend on the water for my livelihood as well, though my canoe rental business on the upper Chicago River would not likely be affected by anticarp measures). At about 10 AM a boat motored to the concrete ledge where we were all gathered to show the news cameras what the men had netted, just a small sample of what would come up in the seines later in the day. We saw a soup-pot’s portion of shiny gizzard shad, each with a daub of black above the eye like a mark of Ash Wednesday atonement, a single whiskered bullhead, and an enormous, ruddy gray common carp. So far, so good. No one will lose his job over a common carp.

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The two species are closely related but they differ slightly in habit and diet—bigheads swim gape-mouthed at the surface in groups, vacuuming algae and tiny creatures that live in it the way a cow might consume grasshoppers with grass; silver carp target even smaller plankton and tend to swim a bit lower in the water, but when startled, as they are by motorboat engines, they flee by leaping, sometimes ten feet in the air. Turn your ski boat in the wrong direction and it’s like running a slalom course through a hail of rain-soaked Sunday papers. Flying silver carp have broken people’s arms, teeth, and even vertebrae.

Multiply Novak’s loss—which he didn’t want to guess at—by all the gear shops, marinas, and charter boats on the shores of the Great Lakes and you may or may not reach $7 billion, the U.S. Fish & Wildlife Service estimate of the impact of sport fishing on the region. But you do reach the desk of Michigan attorney general Mike Cox. Motivated by worried voters, and joined by attorneys general in five other Great Lakes states, Cox sued the state of Illinois, the Army Corps of Engineers, and the Metropolitan Water Reclamation District of Greater Chicago to force them to shut the Chicago locks against the carp. Relying on a 1929 Supreme Court decree that governs the use of the locks for water diversion, Cox went straight to the high court, asking for an emergency amendment to the decree to prevent looming “ecological and economic disaster.”

The White House stepped into the fray and attempted to mollify everyone with money, perhaps fearing charges of favoritism if it did nothing and left the locks open to Illinois commerce and to the carp. At a news conference on February 8 the White House announced a $78.5 million plan to figure out exactly where the fish were, hunt them down north of the barrier, and then strengthen the canal defenses. The Corps of Engineers will also install an additional electric barrier just upriver from the existing one and build a 14-mile concrete and chain-link obstruction along the ridge between the Des Plaines River and the canal, which is often overtopped during heavy rain.

Wenokur and the boatmen of Chicago may actually owe a debt of gratitude to the Michigan attorney general. Cox’s lawsuit did what years of accumulating data couldn’t—he attracted the TV cameras, instigated protests by angry fishermen, and provoked the downtown boat owners, all now pulling together to demand the resources to stop the carp. There’s even funding to study a permanent solution, “ecological separation”—which would disconnect the lake and river ecosystems while still allowing people and commerce to pass. After years of alien species using the canal—mussels invading southward and carp swarming north—we could put a stop to the invasions once and for all.