Tina Lam, Detroit Free Press, November 20, 2009
Great Lakes advocates said today they’ve been told that DNA evidence of one species of Asian carp has been detected above the electric barrier intended to keep the fish out of Lake Michigan.
The DNA was detected in a channel that splits off the Chicago Sanitary and Ship Canal below Chicago, and leads to Lake Michigan, known as the Cal-Sag channel.
DNA testing of water samples near the electric barrier on the Chicago Sanitary and Ship Canal taken beyond the barrier and Lake Michigan on Sept. 23 and Oct. 1 shows the presence of Asian carp about 1 mile south of the O’Brien Lock, about 8 miles from Lake Michigan, the Army Corps of Engineers and other agencies said today.
Previously, DNA of Asian carp has been found a mile below the barrier.
Last week, the Corps and Illinois Department of Natural Resources said they planned to poison nearly 6 miles of the ship canal in early December to kill any possible carp so they would not be able to breach the main barrier when it goes down for maintenance for a few days.
Asian carp have taken over the Mississippi and other nearby rivers and can grow to huge sizes. Because they are voracious feeders and breeders, they are expected to out-compete native fish once they reach the Great Lakes. The Army Corps has built two electric barriers, one experimental and the other permanent, to try to keep them out, but in the past three months, new DNA tests have shown evidence of the carp much nearer to the barrier than scientists had thought.
Barge operators are already upset about the loss of business from the multiday shutdown scheduled for early December. Barges bring oil, coal, cement and other crucial goods through the canal.
The O’Brien lock is the last stop between the Calumet River, where fish DNA has been found, and Lake Michigan.