“The Nature Conservancy said a team of researchers from the University of Notre Dame, Central Michigan University and its own organization found evidence of DNA of Eurasian ruffe in Calumet Harbor, south of Chicago.

Two positive samples from the harbor were collected on July 8. The harbor is at the mouth of the Chicago-area waterway system. Environmental DNA is a surveillance tool that can be used to monitor the genetic presence of aquatic species.

The waterway system is part of an engineered canal that provides an artificial link between Lake Michigan and the Mississippi River basin and has been infiltrated with invasive Asian carp from the Mississippi for years.

That same system has the potential to introduce Eurasian ruffe in the Mississippi, according to the Nature Conservancy. The group said the genetic findings underscore the need for a permanent barrier to block species from moving between the Great Lakes and Mississippi systems.”