CHICAGO, IL (WTAQ) - A new federal report released Wednesday says live Asian carp don’t have to be present for their DNA to be found in the water.

Three federal agencies have identified a half-dozen other ways that genetic material from carp might have reached waterways near Chicago and western Lake Erie.

The report suggests the DNA could have come from storm sewers, sampling gear at fisheries, fish-eating birds, dead fish carcasses, barges and sediments.

Carp DNA from those sources could apparently remain in place for several days.

Asian carp DNA has been discovered in water samples outside an electric barrier set up to stop the invasive fish from reaching the Great Lakes.