Two Chicago-area shipping locks will remain open after U.S. District Judge Robert Dow on Thursday denied granting a preliminary injunction to Michigan and four other states that sought to close them. The two locks are along rivers that feed into Lake Michigan. 

Michigan, Minnesota, Ohio, Pennsylvania and Wisconsin wanted the locks closed and barriers installed to prevent Asian carp from slipping into Lake Michigan. They fear the carp, an invasive species, would then spread and decimate the Great Lakes’ $7 billion-a-year fishing industry.

But Dow ruled Michigan and the other states did not present enough evidence that harm from the invasive species was imminent.  

“In the face of multi-agency efforts to prevent Asian carp migration – efforts that have only increased and expanded in the months since this lawsuit was filed – Plaintiffs have not shown either a sufficient likelihood of success on the merits of their substantive claims or a sufficient prospect of irreparable harm absent the requested injunction,” Dow wrote in his ruling. 

With that, the locks at the mouths of the Chicago and Calumet rivers will remain open. 

The ruling gives the City of Chicago and various business groups a sigh of relief. They had claimed closing the locks would hurt commerce around the Great Lakes and undermine flood control in the Chicago region.