MILWAUKEE — The Wisconsin DNR has detected for the second time DNA from invasive carp in the Milwaukee River.
In June of 2021, routine environmental DNA (eDNA) sampling by the U.S. Fish and Wildlife Service detected bighead carp eDNA at one of the 100 sample locations in the Milwaukee River. Another 150 eDNA samples were collected and analyzed in September of 2021, the DNR said Tuesday - and one of these samples came back positive for invasive carp DNA.
A DNR spokesperson tells us that while they have detected positive invasive eDNA in parts of Lake Michigan in the past, they have never had two positive detections in the same area over a short period of time before.
The discovery has now led the DNR and officials from the U.S. Fish and Wildlife Service to begin sampling the river for bighead, silver, and hybrid carp. The new sampling effort began Monday and will continue through the week.
The eDNA sampling method cannot determine if the positive samples are from invasive fish directly living in the area, or if the samples were indirectly transported from other areas.
None of the invasive fish have been recorded in the area by the DNR, which routinely monitors the river for invasive species. They also ask local anglers to report any invasive fish they find.