TRAVERSE CITY, Mich. (AP) — Asian carp are unlikely to reach the Great Lakes by stowing away on commercial vessels in Chicago-area rivers and canals, the U.S. Coast Guard said Thursday.

Even if the invasive fish somehow got into the ballast tanks of vessels early in their life cycle, they almost certainly would be killed in pumping mechanisms through which they’d have to pass to return to open water, researchers found in a recent study. Ballast tanks are the compartment of a ship that holds water, which helps it maintain buoyancy.