Asian Carp DNA Found in Lake Michigan
via [ Post-Trib ] by Gitte Laasby
DNA from Asian carp has been detected in Lake Michigan for the first time — but it’s still not certain whether the fish themselves have entered the lake, a federal official said Tuesday.
Major Gen. John Peabody of the U.S. Army Corps of Engineers said that two pathways for the carp to reach Lake Michigan are the Grand Calumet River and the Little Calumet River, which might be sampled next.
“We have not sampled in that area, but we will take a look at that,” Peabody said. “Both of those waterways are possible vectors for the migration or the travel of Asian carp or other species between the lake and the Chicago-area waterway system.”
Peabody said federal officials will confer with the Indiana Department of Natural Resources on where water samples should be collected next. A plan should be ready in a month or two.
One sample of genetic material from the invasive carp was found Dec. 8 in Calumet Harbor, which is part of Lake Michigan. Federal officials insisted that does not mean carp have actually reached the lake.
“Our current eDNA process provides indications of likely presence, but it does not yet provide information about Asian carp quantity that may be present, age, size, how they got there or how long they may have been there,” said David Lodge, director of the eDNA project at the University of Notre Dame.
Peabody said no live or dead fish have been spotted in Lake Michigan but that agencies will use netting and other tactics to search for stronger evidence.
The university processes 40 samples a week and has a backlog of 440 samples from the region, he said.
But the Army Corps still doesn’t intend to close the locks and gates that form the final barrier between waterways near Chicago and the lake, he said.
The Supreme Court had refused earlier Tuesday to order the immediate closure of two shipping locks — Navy Pier and O’Brien south of downtown Chicago — to prevent Asian carp from infesting the Great Lakes.
Scientists fear if carp reach the Great Lakes, they could disrupt the food chain and endanger the $7 billion fishery.
Asian carp can grow 4 feet long and weigh 100 pounds while consuming up to 40 percent of their body weight daily in plankton — the foundation of the Great Lakes food web. Scientists have said the carp, which have no predators, could starve out sport fish, such as trout and salmon.
The carp are spooked by passing motors and often hurtle from the water, colliding with boaters forcefully enough to break bones.
The court rejected Michigan’s request to shut the locks and gates temporarily while officials and interest groups debate a long-term strategy. Indiana, Minnesota, Ohio, New York, Pennsylvania and Wisconsin filed briefs supporting Michigan.
The Obama administration opposes closing the locks, saying such action could cause flooding in Chicago and would disrupt the transportation of coal and other commodities on waterways linking Lake Michigan with the Mississippi River system.
Asian carp have been migrating up the Mississippi and Illinois rivers for decades. Federal officials said they weren’t sure how the carp may have come so close to Lake Michigan.
Biologists have speculated that carp might have slipped through the electric barriers when the Army Corps turned off power to them for about a week in October 2008 to do maintenance. Another theory is that the barriers may not have been strong enough, or turned up enough, to fend off younger fish.
– The Associated Press contributed to this report.
Alliance for the Great Lakes response
