The USGS has confirmed that four grass carp have been living in a river that flows into Lake Erie for their entire lives which suggests that it’s certainly possible that other species of carp could be living in a similar proximity to the Great Lakes. The carp that were discovered are thought to be "the result of natural reproduction within the Lake Erie basin."

“It’s bad news,” said USGS biologist Duane Chapman. “It would have been a lot easier to control these fish if they’d been limited in the number of places where they could spawn. This makes our job harder. It doesn’t make it impossible, but it makes it harder.”