Signs of Asian carp in Chicago waterways mean there's a great risk the invasive fish could slip into Lake Michigan at any time, that according to a witness yesterday in the first full day of testimony in a five-state lawsuit.
Michigan, Wisconsin, Ohio, Minnesota and Pennsylvania want a federal judge to close two shipping locks and install barriers to prevent the ravenous fish from overrunning the Great Lakes and potentially devastating its $7 billion-a-year fishing industry.
According to the Associated Press, biologist David Lodge testified for the states saying, "I think there is a risk, a very imminent risk of invasion.” He added that such "invasions are often irreversible."
The city of Chicago, the regional barge industry and others object to closing the locks, arguing the move would undermine critical flood-control measures and hurt businesses that rely heavily on the waterways.
One focus Tuesday was the reliability of genetic testing that Lodge, a University of Notre Dame scientist, said showed Asian carp in the Chicago area.
Those opposed to closing the locks have cast doubt on the so-called environmental DNA tests, which look, not for the fish itself, but for traces of Asian carp DNA.
Some suggest the carp DNA found near Lake Michigan could have been transported in barges' ballast water and bird droppings. If it was, they argue, that could mean the fish themselves aren't necessarily present.
But Lodge insisted that by far the most plausible explanation for the DNA is that it came from discarded cells of carp living in the waterway. DNA can degrade within hours, he said, so it probably wouldn't have survived transport in a barge or a bird.
Lodge conceded, however, the DNA tests can't determine whether there is just one carp in an area or hundreds.
The lawsuit, filed in U.S. District Court in northern Illinois, accuses the U.S. Army Corps of Engineers and the Metropolitan Water Reclamation District of Greater Chicago of creating a public nuisance by operating locks, gates and other infrastructure through which the carp could enter the lakes.
The U.S. Supreme Court has twice rejected state pleas to close the locks, but did not rule on the merits of the legal claims.