Illinois officials remain on high alert, following the discovery of an Asian carp caught in late June on the wrong side of electric barriers built near Chicago to keep the invasive species from entering Lake Michigan.
The discovery of the fish in the Calumet River, nine miles from Lake Michigan, comes as federal and state officials have renewed calls for the release of a U.S. Army Corps of Engineers study that could offer “a range of options and technologies” to tackle the threat of Asian carp and other invasive species. The report’s release was delayed by the Trump administration in February.
By tracing where this single carp had lived, researchers hope to prove whether the fish breached a series of three barriers used to block the species from entering the Great Lakes. The carp, which can grow up to 110 pounds and eat 20 percent of their weight every day, have spread up the Mississippi River and other Midwest waterways over the last several decades.
A two-week search conducted in response to the June 22 capture of the fish found no evidence of other Asian carp above the barrier, located about 37 miles from Lake Michigan, officials said on Monday.
An inquiry into this carp’s origin is still underway, said Greg Whitledge, a Southern Illinois University zoologist. His team plans to examine the fish’s DNA as well as the chemistry of calcium deposits in its ear bone to trace the waterways in which it had traveled. Those findings will be released later in July.
“This is an approach at my lab at SIU has pretty commonly used to get information about the environmental history of various fish species in the Midwest here, especially the rivers, but the Chicago area as well,” Whitledge said.
Whitledge said after several weeks of work, the fish was identified by authorities as being a mature male Silver carp thanks to an analysis by the U.S. Fish and Wildlife Service.
Silver carp are one of four Asian carp species including the…