A federal judge in Chicago denied the request of several Great Lakes states, including Wisconsin, to shut two of Chicago’s navigation locks to prevent the spread of Asian carp.

Asian carp are a voracious and prolific foreign species that can grow
up to four feet and weigh 100 pounds. The carp have been making their
way up the Mississippi and Illinois rivers toward the Great Lakes for
years.

Despite attempts by the Michigan-led, five-state coalition to prove leaving the locks open threatens the Great Lakes with invasive species, Judge Robert Dow Jr. said in his ruling Asian carp are still only a potential threat.

“At the end of the day, plaintiffs have not carried their burden of showing that the balance of the harms weighs in their favor,” Dow said.

Dow said evidence of harm associated with closing the locks, including increased flooding and sanitary concerns, outweighed the potential for Asian carp invading the Great Lakes.

Firm evidence proving the carp have made their way into Lake Michigan in large numbers has so far proved elusive, though, aside from carp DNA found near the lake.

Despite the setback, the Wisconsin Department of Justice remains confident Wisconsin will continuing fighting against the invasive species.

“We are deeply disappointed by the decision. We are continuing to consider our options in cooperation with the other Great Lake states,” said DOJ spokesperson Bill Cosh.

The states filed the lawsuit this summer after the U.S. Supreme Court refused to get involved in the dispute or force Chicago to close its locks.

The U.S. Army Corps of Engineers is also currently in the throes of studying the effects of Asian carp of the ecology of the waterways.

However, neither Wisconsin nor the rest of the states in the lawsuit will be able to use that information to appeal until the study is completed in 2015.

Although Wisconsin may not be pleased with the decision, some Chicago-area businesses that depend on the locks were pleased.

“Ultimately, Judge Dow recognized that fear and speculation were not
enough to justify the economic impacts that lock closure would have
inflicted on the region,” said David Rieser, the lead attorney for the
Coalition to Save Our Waterways, in a statement.