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Keep Asian carp out of lakes, or we will regret it

- Editorial from Eric Sharp: Free Press Columnist

When the fight against the sea lamprey in the Great Lakes started 50 years ago, no one dreamed the parasites would still be destroying large numbers of lake trout, especially after governments had spent $250 million on the battle.

Probably the most important lesson we have learned from the lamprey mess is that once an exotic species gets established in the Great Lakes, it's there to stay. Efforts to keep the damage caused by sea lampreys to tolerable levels will be unending and expensive.

By the late 1990s, it looked as if attempts to poison lampreys and keep them out of spawning streams with electrical barriers and raised weirs were working. But we forgot about the St. Marys River, which turned out to be a lamprey factory, producing so many each year that virtually every lake trout in northern Lake Huron was killed before it reached spawning age.

Scientists have since found ways to minimize the number of lampreys the St. Marys and other streams churn out, but if we ever stop those control efforts, we'll see lake trout disappear again. The lamprey also taught us some lessons about the politics of controlling exotic species. And those lessons are important, because we might be on the verge of repeating the mistakes of the lamprey era in dealing with a new threat to the lakes, exotic Asian carp.

Bighead and silver carp either escaped from or were released by catfish farms in the South. In less than 10 years they have spread up the Mississippi River system and been collected in the Chicago Sanitary and Ship Canal only 25 miles below Lake Michigan. Some people say they have seen them 11 miles below the lake.

About a month ago, the U.S. Army Corps of Engineers turned on an electrical barrier in the Chicago canal designed to keep the bighead carp at bay. But it took so long to get the money to build and run the barrier that no one knows if the carp, which can exceed 100 pounds, are already above it. In addition, the barrier is an experimental project, and the money to operate it runs out in about 18 months. And an even more immediate problem is the lack of a backup generator to keep the barrier going if the commercial power supply fails. "One power failure could jeopardize the effectiveness of the barrier," said Mark Gaden, a spokesman for the Great Lakes Fisheries Commission. "We've asked Congress for funds to mediate that."

So far, Congress hasn't come through. Maybe that's because the amount needed is too small to draw attention. A $150,000 generator could be all that's standing between the Great Lakes and another environmental disaster, but things like that tend to get overlooked by people who hold onto their jobs by funneling millions or even billions of dollars to get votes and campaign contributions.

But failure to act on these environmental threats can be incredibly costly. Chris Goddard, executive secretary of the fisheries commission, figures that in the past 15 years, fixing damage from zebra mussels has cost governments and business along the Great Lakes hundred of millions of dollars.

A second barrier in the Chicago canal would cost about $350,000 to install and $100,000 a year to maintain. Even the larger figure is a fraction of the cost of some junkets the State Department puts on for bigwigs.

Like zebra mussels, bighead and silver carp are filter feeders. But they also are thousands of times the size of a zebra mussel. They don't filter plankton from open waters but live by sucking in algae and detritus from the bottom.

Asian carp aren't much use as a sport fish, and they have the ability to root up bottom vegetation and turn rivers and lakes into mud pits. But even scarier is that in some of the big pools along the Mississippi, they have multiplied so quickly that in less than a decade they make up 90 percent or more of the fish life.

Biologists worry that a few million of them sucking up the water of the Great Lakes could disrupt the food chain and lead to a collapse of major sport and commercial species like salmon, walleyes and perch.

They also worry about what would happen if bighead and silver carp get into tributary rivers.

The truth is that no one is sure what bighead and silver carp would do to the ecology of the Great Lakes if they become established there. But if our experience with sea lampreys and zebra mussels is anything to go by, we probably don't want to find out.

* Tue, 7/23/2002

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