Here's an excerpt:
"Nov 2013 - In October 2013, the U.S. Geological Survey confirmed the first evidence that grass carp are naturally reproducing in the Great Lakes, specifically in the Sandusky River, Ohio, a tributary of Lake Erie.
FOCA’s Tracy Logan adds, 'this development may be a strong indicator that the more troublesome related species (Silver and Bighead Carp) may also be able to self-sustain a breeding population in the Great Lakes.' "
For more see:
FOCA Asian Carp