Patti Zarling

Green Bay (Wis.) Press-Gazette

GREEN BAY — Wisconsin natural resources officials say they've identified a genetic sample indicating invasive Asian carp may have found their way into the Fox River in the Green Bay area.

A single positive sample found this summer does not necessarily signal the presence of live fish, according to Wisconsin Department of Natural Resources officials.

The department reported Tuesday it is working with the federal Fish and Wildlife Service to collect more samples in the next two weeks to learn more.

Asian carp pose significant ecological and economic threats to the Great Lakes region and its fishery because they eat voraciously and compete with native fish for food, according to the DNR.

Tests for DNA are sensitive and can detect material shed in mucus or waste from fish, or from birds who have eaten the fish elsewhere, Bob Wakeman, aquatic invasive species coordinator for the DNR, noted in a written statement. Bilge water from boats also could carry traces of the fish.

Multiple positive tests over time indicate the likelihood of live fish, Wakeman said.

In addition to the federal DNA monitoring, DNR fisheries team members conduct a variety of netting, electroshocking and trawling operations in state waters as part of a ongoing monitoring effort.

To date, these efforts have not captured any Asian carp in any waters of the Fox River near Green Bay, Green Bay or Lake Michigan.

The species includes bighead and silver carp and the fish were introduced into the southern U.S. in the 1970s, according to the DNR. The DNA has been found upstream of barriers in Lake Calumet, seven miles from Lake Michigan on the Indiana-Illinois border, as well as in Lake Erie, the DNR noted.