CHICAGO -- Illinois environmental officials will dump a toxic chemical into a nearly 6-mile stretch of the Chicago Sanitary and Ship Canal Wednesday to keep the voracious Asian carp from entering the Great Lakes while an electrical barrier is turned off for maintenance.
The fish, which can grow to 4 feet long and 100 pounds and are known to leap from the water at the sound of passing motors, have been found within a few miles of Lake Michigan and there is evidence they might have breached the barrier, designed to repel them with a non-lethal jolt.
Environmentalists fear the fish, which consume up to 40 percent of their body weight daily in plankton, would starve out smaller and less aggressive competitors and possibly lead to the collapse of the Great Lakes sport and commercial fishing industry.
The fish toxin rotenone will be spread Wednesday evening near Lockport, Illinois Department of Natural Resources spokeswoman Stacey Solano said. After about eight hours, crews will use large cranes with nets to scoop up an estimated 200,000 pounds of dead fish, she said.
The carcasses will be disposed of in a landfill, Solano said. The U.S. Army Corps of Engineers plans to perform the maintenance on the barrier.
"We just want to make sure that there is no possible way that Asian carp can breach the barrier while it's down for maintenance," Solano said. "That's the main objective of this operation."
Environmental groups say they support the operation but are urging federal officials to close three locks in the Chicago area that lead to Lake Michigan until they can determine a permanent solution.
"If there ever is a last ditch effort, this is it," said Joel Brammeier, acting president of the Chicago-based Alliance for the Great Lakes. "Everybody I talk to I tell them we have to close those locks."
Corps of Engineers and U.S. Environmental Protection Agency officials said they are considering every alternative, but have not made a decision on closing the locks.
Asian carp escaped from Southern fish farms into the Mississippi River during 1990s flooding and have been migrating northward since.
Last month, officials announced that DNA samples of the Asian carp recently were found between the barrier and Lake Michigan, although the fish had yet to be spotted in the area.
Aside from decimating species prized by anglers and commercial fishers, Asian carp are known to leap from the water at the sound of passing motors and sometimes collide with boaters.
Early Wednesday, the DNR will remove and relocate any sport fish from the canal so they are not harmed by the rotenone, Solano said. She estimated the cost of the operation at between $1 million and $2 million.
Solano said the rotenone should naturally dissipate after it is spread, but the department will spread another chemical to help accelerate that process. Rotenone has been used for 40 years in Illinois, and "if used properly there should be no affect to humans or other wildlife," she said.
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