Fish kill called necessary to save the Great Lakes
Saying ecosystem is threatened, officials use poison on invasive carp

By Kari Lydersen and Peter Slevin
Washington Post Staff Writer
Sunday, December 6, 2009

LOCKPORT, ILL. -- The poisoned fish began floating to the surface in the cold Illinois dawn, but as scientists and ecologists began hauling their lifeless catch to shore, they found only one carcass of the predator they targeted -- the ravenous Asian carp.

Never before have Illinois agencies tried to kill so many fish at one time. By the time the poison dissipates in a few days, state officials estimate that 200,000 pounds of fish will be bound for landfills. But they say the stakes -- the Great Lakes ecosystem and its healthy fish population -- could hardly be higher.

Asian carp have slowly been making their way up the Mississippi River and its tributaries, shifting the ecological balance as they devour enormous quantities of plankton that once sustained other species.

Neither prayers nor multimillion-dollar electronic fences have stopped the carp, which commonly grow to a fat-bellied four feet long. Amid fears that the fish are drawing closer to Lake Michigan on the Chicago Sanitary and Ship Canal, scientists turned to a poison called rotenone.

"It's time to man the barricades. We've simply got to protect the Great Lakes at all costs," said John Rogner, assistant director of the Illinois Department of Natural Resources, which is leading the chemical attack while an electronic fence is being repaired.

But where are the carp?

"I expected to see boatloads of Asian carp coming in. You can't escape rotenone," said Dan Thomas, president of the Great Lakes Sport Fishing Council. "As far as the fishing community is concerned, no news is good news."

By Friday, state officials had identified one dead 22-inch fish as a bighead Asian carp.

"That doesn't mean there weren't other carp in there," said Noah Hall, executive director of the Great Lakes Environmental Law Center. "We may be at the point where a few have gotten through, but it's not too late to prevent carp from getting established in the Great Lakes."

A bustling encampment of 350 specialists and volunteers now occupies a stretch of the canal, built in the 1890s to carry sewage away from Chicago and its supply of drinking water. A flotilla of small boats crisscrosses the steel gray waters in below-freezing temperatures, looking for Asian carp.

By Friday, state officials patrolling a six-mile stretch of canal were netting dead common carp and thousands of other "rough fish" not valued by fisherman. Earlier, bass and other sport fish had been collected and transported to safe waters with the use of electric shocks, which stunned but did not kill them.

Department of Natural Resources spokesman Chris McCloud said that the early results are inconclusive and that Asian carp could still surface: "In terms of deciding whether there are or are not Asian carp or how many, we just don't know."

Michigan politicians, meanwhile, called for urgent action to stop the carp before they reach Lake Michigan. Although it remains unclear whether the large fish could thrive in slow-moving lake waters with less plankton, they do not want to take a chance.

"Asian carp would most likely devastate the Great Lakes fishery," Sen. Carl M. Levin (D-Mich.) told a Senate subcommittee on Thursday. Michigan Gov. Jennifer Granholm (D) signaled that her administration is considering a lawsuit to pressure Illinois to stop the fish.

For all the hype and hoopla, there is something prosaic about the prospective carp infestation. Jack Darin, director of the Illinois chapter of the Sierra Club, said, "We are rapidly discovering that we have a priceless national -- indeed, global -- asset that is surprisingly vulnerable to fish."

State and federal authorities have already spent more than $10 million in Illinois to stop the Asian carp, descendants of fish imported from China 35 years ago by catfish farmers in the Deep South. Escaping their pens when floodwaters rose, they have been moving north, consuming as much as 50 percent of their weight each day in plankton and other microorganisms. One fish can carry 3 million eggs.

On average, about 10,000 silver carp, a member of the Asian carp family, occupy each mile of the Illinois River, said river ecologist Kevin Irons, who conducts studies for the Illinois Natural History Survey. Native fish competing for the same food supply are becoming thinner, he said.

Two electronic barriers are in place along the Sanitary and Ship Canal, and the Army Corps of Engineers is using at least $6 million in federal stimulus dollars to build a stronger one. The estimated completion date is September 2010, said the Corps's Great Lakes division commander, Maj. Gen. John W. Peabody.

When Peabody gathered members of his staff last year and asked them to contact their sources, he found that no one could say with confidence how close the carp were to Lake Michigan.

Tests commissioned by the Corps and conducted by the University of Notre Dame's Center for Aquatic Conservation found silver carp DNA one mile below the electronic barriers, much closer than believed. More worrisome, scientists found DNA in several places beyond the barriers and much closer to the lake.

"What we don't know is how our DNA relates to the abundance of fish in any area," said David M. Lodge, a Notre Dame biology professor. "All it tells us is there were fish here."

Opinion is divided on how Asian carp would fare in the 94,000-square-mile Great Lakes, which hold the world's largest surface supply of fresh water.

The waters are colder and contain less plankton, said Irons, who thinks it most likely that carp would move on to smaller lakes and waterways, perhaps establishing themselves in marinas or lagoons.

"Even if a few of those fish make it, it still is not game over," Duane Chapman, a U.S. Geological Survey researcher, said. "The chance of them dying before they can figure out how to make a living in the Great Lakes is good."

The risk is great enough that Darin and the leaders of a number of local national environmental groups favor closing off Lake Michigan from inland waterways . Granholm raised the possibility of closing the canal, blocking access to barges traveling to the Mississippi.

"Whether or not we are successful in stopping this particular invader, there are going to be more," Darin said. "This may be the most destructive force that we've seen yet for the Great Lakes ecosystem, but it won't be the last."

© 2009 The Washington Post Company