DNR: Despite DNA evidence, no Asian carp in Chicago River
Chicago — Asian carp DNA in the Chicago River does not worry DNR like it used to. They are looking for the entire fish and so far they have been mostly unsuccessful.
When the “eDNA” of Asian carp, or DNA found in the water and not on the fish, started showing up near downtown Chicago about four years ago, DNR responded to what it saw as evidence that the large, hungry, and prolific Asian carp was trying to get from the Mississippi River to Lake Michigan and the Great Lakes. The Chicago River is one of five pathways.
In October 2014, the U.S. Fish and Wildlife Service collected 57 samples from the river and found the DNA of silver carp, a variety of Asian carp, in five of the samples.
In recent years, DNR has learned more about eDNA and they have learned more about Asian carp.
“Our understanding of eDNA has changed,” said Kevin Irons, manager of DNR’s Aquaculture and Aquatic Nuisance Species Program. “We don’t react to eDNA alone.”
The Asian carp DNA they are finding in the Chicago River may very well have got there on the hulls of boats or by birds that ate the fish.
“Not only can one meal of carp spread eDNA, but the way their digestive system works, it will spread eDNA for a week.”
Irons said DNR has been trying to find Asian carp north of electric barriers near Romeoville, about 31 miles southwest of Chicago.
“We spent thousands of hours out there with commercial fishers. We caught a bighead carp in Lake Calumet in 2010 but haven’t caught anything since.”
The closest they believe larger numbers of Asian carp have got to Lake Michigan is 55 miles away on the Des Plaines River and that is as close as they will ever get because, said Irons, the carp does not like the state’s small rivers.
Asian carp came here from the Mississippi River, the fourth longest river in the world, but he points out their native habitat is the Yangtze River, the third longest. While there is plenty of food for them on the Chicago River, they seem to lose interest the closer they get.
“They’ll stray up. They’ll go up below the Brandon Lock and Dam. But they don’t seem to linger there,” he said. “The Asian carp, they’ll go up there and then they’ll turn around and go back downstream.”
Since 2010, DNR estimates it has removed 160,656 Asian carp from Illinois waterways. In Will County Forest Preserve alone, 900 Asian carp were removed. And they are not taking chances. Thirty-two bighead carp have been removed from landlocked ponds in the Chicago area.
The recently released results of October eDNA sampling data “show the presence of bighead or silver carp DNA throughout the Chicago Area Waterway System,” according to the Alliance for the Great Lakes, the National Wildlife Federation, the Illinois chapter of the Sierra Club and other organizations.
“Most alarming is detection of carp DNA very near the lock in downtown Chicago – less than one city block from Lake Michigan,” the groups stressed.
In January 2014, the U.S. Army Corps of Engineers issued a study to Congress detailing ways to prevent Asian carp and other invasive species from taking over the Great Lakes. Some of those efforts could cost billions of dollars and take decades to finish.
Since a report on the study was issued, the Chicago Area Waterway System Advisory Committee has been discussing short- and long-term Asian carp solutions. According to the environmental groups, the advisory committee is working toward a deadline of Dec. 15, 2015, to reach a consensus on prevention measures.