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Scientists favor dividing Great Lakes, Mississippi

Asian bighead carp swim an exhibit last year Chicago’s Shedd Aquarium.  Asian carp have long been seen as severe

Asian bighead carp swim in an exhibit last year at Chicago’s Shedd Aquarium. Asian carp have long been seen as a severe threat to the Great Lakes. | AP

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Updated: August 30, 2011 12:19AM

TRAVERSE CITY, Mich. — No additional study is necessary to prove that separating the Great Lakes and the Mississippi River systems is the only way to prevent invasive species such as Asian carp from migrating between them and doing serious ecological and economic harm, a team of scientists said Thursday.

In a newly released paper, the scientists said opponents of severing the man-made link between the two watersheds were spreading myths, including that electric barriers are enough to stop the unwanted carp from entering Lake Michigan through a Chicago-area shipping canal.

Opponents also have claimed falsely that it’s too late to keep the carp out of the lakes, or they can’t survive in the lakes because of inadequate food and spawning habitat, or even if they do spread in the lakes they won’t do much damage, the scientists said. Their article in the Journal of Great Lakes Research urges Congress to approve legislation ordering the Army Corps of Engineers to quicken a study of whether to divide the two freshwater basins, now due for completion in 2015.

“The task at hand needs to be not if, but how to solve the problem,” said Jerry Rasmussen, a consultant and retired U.S. Fish and Wildlife Service invasive species expert.

Mark Biel, chairman of a business and industry coalition called UnLock Our Jobs that the scientists singled out for criticism, said their article was biased.

“The issues this report claims to address have been asked and answered repeatedly,” Biel said. “It’s time we move on to maintaining and improving current barriers as well as implementing comprehensive solutions across the region. Separation simply isn’t one of them.”

His group contends that dividing the basins or closing shipping locks would cost billions and devastate a regional economy that depends on movement of cargo on northern Illinois waterways.

Asian carp are voracious filter feeders that can reach 4 feet long and 100 pounds. Imported decades ago to gobble algae from Deep South fish farms and sewage treatment plants, they escaped into the Mississippi and have moved northward since. An electric barrier network on the Chicago Sanitary and Ship Canal about 25 miles from Lake Michigan is designed to bock their path.

State and federal agencies are using other methods to keep Asian carp out of the lakes, including stepped-up commercial fishing.

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