VIDEO: Invasive Grass Carp Eggs Found Near Lake Erie

The threat of an Asian carp invasion into the Great Lakes continues to mount.

A new issue is giving scientists some pause.

Grass carp eggs have been found in the Sandusky River connecting to the western basin of Lake Erie.

Marc Gaden with the Great Lakes Fishery Commission says grass carp are a type of Asian carp and have been in area waters for the last 20 to 30 years.

The fish come from private ponds in hatcheries and golf courses.

He says the fish aren't supposed to be able to produce eggs, so the finding this summer is concerning.

"They're supposed to be sterile, so whenever you find fertile grass carp, it's certainly cause for concern and when you find grass carp eggs of any kind, it's cause for concern," says Gaden. "There shouldn't be any grass carp eggs in the [Great Lakes] let alone the 7,000 that were collected."

Gaden says finding the thousands of grass carp eggs doesn't necessarily mean the population has been able to take hold in the Great Lakes.

"We don't know if this represents the continuity of these carp barely hanging on and kind of humming in the background as they have been for many decades, or if this represents actually the leading edge of an invasion," says Gaden.

Gaden adds while it's not clear the grass carp are entrenched in the area, he knows doing nothing would all but ensure an invasion.

"Grass carp could become established in the Great Lakes if nothing is done to try and keep them under control and that their spread throughout the Great Lakes would complete within the matter of about a decade," says Gaden, adding the fish can be especially destructive.

"They destroy vegetation, this is places where fish need for nursery habitat or birds hang out," says Gaden, "It's places where people like to visit in wetlands to bird watch or to fish or duck hunters, so, the impact could be quite substantial if grass carp were to become established in the Great Lakes; we're very concerned about that."

The eggs were found by representatives from US Geological Survey, Ohio Department of Natural Resources and the University of Toledo from May 30 to July 12.

Gaden says joint efforts between Michigan, Ohio and Ontario continue to spot the invasive species early and prevent the population from gaining a foothold in the local environment.