Environmental DNA tests last week were positive for Asian Carp in the Chicago river.
Experts say additional research is needed but the DNA could be coming from a fish market.
The positive Environmental DNA tests were cause for alarm - officials with the Michigan DNR reiterated the urgency around installing a barrier to keep Asian Carp from reaching Lake Michigan.
The tests were within Chicago - close to Lake Michigan - and showed multiple positive hits for Asian Carp.
Kevin Irons is with the Illinois DNR. He said scientists use environmental DNA as potential early indicator of Asian Carp presence - but it doesn’t necessarily mean the Carp are alive.
“The US Army Corps of engineers did a study five or six years ago and it showed that eDNA was detectable in the sewers in the Chicago area, specifically out of Chinatown where they are readily eaten,” he said.
eDNA from a fish market could have made its way into the city sewer system, according to Irons.
“Ice or bloody ice from the fish delivery of dead fish, mind you, can find its way into the sewer system,” he said.
Irons said after a heavy rain the sewer system is sometimes released into the river. One place that happens is on Bubbly Creek, where he said the eDNA was discovered.
It’s possible, Irons said, that a release from the sewers is what caused the recent high count of Asian Carp eDNA.
But, he said, researchers are doing additional testing to be sure.