New DNA tests are giving scientists hope they can change the focus of the fight against Asian carp.
The tests are called environmental DNA, and they've indicated both bighead and silver carp living close to and in Lake Michigan near Chicago.
A peer review published this week confirms the invading carp above a pair of electric barriers intended to keep them out of the Great Lakes.
While the tests aren't good news, this week's article could help focus the fight, said Nature Conservancy scientist Lindsay Chadderton, but the tests don't reveal how many carp live above the barriers.
"We know that we're dealing with more than one fish, but we don't know if it's 100 or 1,000," she said.
Asian carp have quickly infested the Mississippi River system. The voracious fish push out native species, while silver carp are known for their leaping when startled, at times injuring boaters when leaping from the water.
"We would hope that now the paper has been published that we can shift the debate from talking about the validity of the eDNA method to actually starting to identify what are the pragmatic, practical solutions that we can take to prevent establishment of carp within the Great Lakes, and the further spread of carp into the upper canal waterway," Chadderton said.