The DNR says there's evidence that the carp, which can grow to 60 pounds and outmuscle native species for food, are in the St. Croix River. However, Wisconsin DNR officials say the barriers aren't 100 percent effective and it may be a worthless effort at this point.

Natural resources experts worry the invasive fish will out-eat native species, which could have a serious impact on the the state's fishing industry and tourism, and now the DNR has found evidence the fish has made it north of the Twin Cities.

A biologist tells MPR that lab tests have confirmed the silver carp has swam as far as Lock and Dam No. 1. Researchers are awaiting word on whether the fish has also reached the mouth of the Minnesota River.

A privately funded group continues work on a fast-track plan to stop invasive Asian carp from reaching the Great Lakes. The group hopes to release its plan in January. The Detroit Free Press reports one of the options includes a series of barriers in the Illinois River to stop the destructive species from traveling from the Mississippi River through Chicago to Lake Michigan. Minnesota is part of a suit to force federal officials to speed up the effort to halt the fish before they spread further.

The New York Times looks at how the invasive species is sometimes pitting neighbors against one another. For example, some states are pursuing legal action to build a barrier cutting off the Mississippi River from the Great Lakes, but Illinois is fighting back, saying that would leave Chicago unable to control floods and interfere with shipping.