From CBS News:

A bighead carp caught near Lake Michigan in June likely lived nearly its whole life in waters from the Great Lakes, tests show.

The nine-kilogram fish captured in Lake Calumet on June 22 was the first Asian carp caught on the wrong sRead moreide of underwater electric barriers near Chicago intended to keep the invasive species from moving up the Mississippi River system into the Great Lakes and adjoining waters.

Researchers at the Southern Illinois University Carbondale Fisheries and Illinois Aquaculture Center analyzed the chemical markers in the inner ear bones of the fish and released the results Thursday. Read more.