(AP) -- A decision could come within days on whether to temporarily close a vital Chicago area shipping waterway in an increasingly desperate bid to stop the invasive Asian carp from reaching the Great Lakes, an Obama administration adviser said Friday.
Cameron Davis, the Great Lakes adviser to the U.S. Environmental Protection Agency, told The Associated Press that discussions were under way about shutting the O'Brien Lock while crews poison part of the Chicago Sanitary and Ship Canal to kill the giant carp.
"It's going to happen soon," he said about a decision. "We're talking, best guess, within the next two or three days."
Before making a final decision, officials want to finish searching for Asian carp and conduct other tests along the canal to pinpoint where they might be located, Davis said. If officials do chose to close the lock, it would shut down immediately.
Authorities are trying to make sure the voracious carp don't get into Lake Michigan where it could starve out smaller, less aggressive competitors and cause the collapse of the $7 billion-a-year Great Lakes sport and commercial fishing industry.
But closing the lock could also disrupt the movement of millions of tons of iron ore, coal, grain, salts and other goods.
The American Waterways Operators, a trade association representing the tug and barge industry, said Friday that closing the lock would lead to higher shipping costs because commodities would have to be sent overland via truck or train.
It said the lock would be closed for a minimum of 10 days and cautioned that a lack of advance notice would show "a lack of understanding and consideration by the agencies of the economic impact of the shutdown."
A sense of urgency among environmentalists rose on Thursday after officials said they found a single Asian carp during a fish-kill operation this week in another part of the canal. It was the closest that an actual fish has been found to Lake Michigan.
Last month, officials said they found DNA evidence that the carp may have breached an electrical barrier on the Chicago Sanitary and Ship Canal that is meant to hold back the fish from the lakes. Michigan Gov. Jennifer Granholm and five environmental groups have threatened to sue if the U.S. Army Corps of Engineers to force it to temporarily shut three locks near Chicago over fears the carp will creep into the Great Lakes.
The carp - which can grow to 4 feet long and 100 pounds and are known for leaping out of the water when boats are near - were imported by Southern fish farms but escaped into the Mississippi River during flooding in the '90s and have been making their way north ever since.
The Mississippi and the Great Lakes are connected by a complex, 250-mile network of rivers and canals engineered more than a century ago. It runs from Chicago, on the southern edge of Lake Michigan, to a spot on the Mississippi just north of St. Louis.
In the ongoing battle against the Asian carp, environmental officials began dumping poison Wednesday in a nearly six-mile stretch of the canal to kill off any Asian carp while the electrical barrier was turned off for maintenance. Work was expected to finish on Saturday.
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