The largest fish kill in Illinois history -- expected to net 100 tons of fish including, hopefully, some Asian carp -- is to start Wednesday south of Chicago in an attempt to make sure none of the feared carp make it past an electric barrier while it is shut down for maintenance.
The fish kill is necessary because DNA testing since July has shown evidence of two species of invasive Asian carp near the barrier. And in the latest round of testing last month, carp DNA was found beyond the barrier, just one lock and dam away from Lake Michigan.
"If we don't let huge numbers get past, we could prolong a major invasion of carp for years," said Becky Cudmore, an Asian carp expert with Canada's Department of Fisheries and Oceans. "The barrier is still the best thing we have to keep them out."
The huge operation will spread rotenone into a 5.5-mile stretch of the Chicago Sanitary and Ship Canal near Lockport, Ill.
The poison will kill all the fish, and scientists want to see if there are indeed Asian carp among them, as DNA evidence has shown. Once the fish are dead, power will be shut off at an electric barrier that has been turned on only since April. An older barrier that operates at a lower voltage will stay on as a backup.
Cudmore, one of 18 Canadians taking part in the operation, said that even though the bighead and silver species of Asian carp appear to have breached the electric barrier, all is not lost.
"We definitely feel the Great Lakes are at risk, but that risk is not immediate," she said. If only a few carp make it into Lake Michigan, it could take years for them to become a problem.
Hundreds of people from federal and several states' agencies are to help with the fish kill and cleanup, which could last into the weekend.
Maintenance on the barrier is expected to last at least four days; barges were ordered off the canal until Dec. 18.
(c) 2009, Detroit Free Press.
Visit the Freep, the World Wide Web site of the Detroit Free Press, at www.freep.com
Distributed by McClatchy-Tribune Information Services.
Explore further: Stanford researchers rethink 'natural' habitat for wildlife