A single positive sample for Silver Carp showed up in Sturgeon Bay near Door County’s Potawatomi State Park.
The water was drawn late last May, but at the time scientists weren’t monitoring for carp at all, they were in the midst of a Lake Michigan-wide survey for signs of another type of invasive fish, call the Eurasian Ruffe. A University of Notre Dame laboratory lead the project.
Scientists were not on the look out for signs of Asian carp in the water samples until this fall. Officials say results emerged last week. They don't yet know if the DNA came from a live fish or some other source, such as droppings from a bird that ate Asian carp.
The is not the first genetic material from the invasive fish found in Lake Michigan; researchers pick up an earlier hit in Chicago's Calumet Harbor.
Concern around potential threat of Asian carp to the Great Lakes has smoldered for several years as biologists continued their hunt for the invasive in and around the Chicago Sanitary and Ship Canal. It connects the carp-filled Mississippi River basin to Lake Michigan.