CHICAGO (AP) — Federal officials announced Friday that they will begin intensive monitoring of waterways near Lake Michigan next week after genetic material from the invasive Asian carp showed up in a third consecutive round of testing.
Crews will use electric jolts to stun fish, sweep the waterway with half-mile-long nets and conduct additional sampling in Lake Calumet and the Calumet River near Chicago during a four-day period beginning Monday, the Asian Carp Regional Coordinating Council announced Friday.
DNA from silver carp, one of two Asian species threatening to enter the Great Lakes after migrating northward from the South for decades, was found in 11 samples in the lake and the river during testing in July. The U.S. Army Corps of Engineers announced on July 22 that it had found two additional samples containing DNA from silver carp and would increase its response if DNA was found in a third sample.
Some scientists say if the large, voracious carp establish a foothold in the Great Lakes, they could unravel the food web by gobbling plankton needed by smaller fish that feed prized sport varieties such as walleye and trout. Environmentalists and officials from several states are calling on the corps to immediately close shipping locks that separate the Great Lakes and Mississippi River watersheds to stop the carp.
It is unclear from the sampling whether live fish are in the lake or if genetic material came for dead fish or was carried into the lake from bilge water, said Chris McCloud, Illinois Department of Natural Resources spokesman.
"We're going to take this one step at a time, then we will make informed decisions," McCloud said.
He said biologists will take more samples Monday, then begin electrofishing and netting through Thursday. If at least one carp is found, those steps would be intensified; if two or more are found, officials would evaluate whether to use a toxin to kill the carp, McCloud said.
"We remain vigilant both in monitoring to keep Asian carp out of the Great Lakes, and also in investigating all possible sources of Asian carp DNA to minimize the human transfer element such as people unknowingly using Asian carp as bait or other activities that could transfer them to the Great Lakes," John Goss, director of the White House Council on Environmental Quality, said in a written statement.
The samples were taken above an electric barrier about 25 miles from Chicago designed to prevent aquatic species from moving between the Great Lakes and Mississippi River basins.
Federal officials contend the barrier is working well and there's no evidence any Asian carp have passed through it. Just one live Asian carp has been found on the Lake Michigan side of the barrier.
But environmentalists say the federal and Illinois governments must act more quickly and forcefully to ensure the carp don't reach the Great Lakes.
They favor placing structures in Chicago-area waterways to sever the century-old, man-made link between Lake Michigan and the Mississippi system. The Army Corps is studying that and other possible methods of preventing aquatic species from moving between the two basins, but its report is scheduled for release in 2015. Critics say that's too slow.
Five states — Michigan, Minnesota, Ohio, Pennsylvania and Wisconsin — have filed a federal lawsuit demanding quicker action.