Invasive round goby fish have impacted fisheries in the Great Lakes and the Finger Lakes by competing with native species and eating the eggs of some species of game fish.

But the camouflaged bottom dwellers can be difficult to find and collect—especially when they first enter a new body of water and their numbers are low and they might be easier to remove.

In a proof-of-principle study, Cornell researchers describe a new technique in which they analyzed environmental DNA—or eDNA—from water samples in Cayuga Lake to gather nuanced information about the presence of these invasive fish.