The Seventh Circuit Court of Appeals has denied requests by the attorneys general of Michigan, Minnesota, Ohio, Pennsylvania, and Wisconsin for an order requiring the U.S. Army Corps of Engineers (Corps) to take measures to halt the migration of Asian carp into the Great Lakes. Michigan v. Corps, No. 10-3891 (7th Cir. 8/24/11). The appellate court upheld a December 2010 U.S. District Court for the Northern District of Illinois decision rejecting the states’ motion for a preliminary injunction. The lower court concluded that the invasive species did not appear to be an imminent threat and that closing Chicago-area shipping locks might not keep the carp from reaching Lake Michigan.

Locking gates were built into the Calumet-Saganashkee Channel and the Chicago River to limit the amount of water leaving Lake Michigan when engineers reversed the river’s flow at the turn of the 20th century. The Corps and the Metropolitan Water Reclamation District control the locks to limit flooding during heavy rains and to allow cargo ships and boats to pass.  

The appeals court held that ongoing federal efforts to prevent the fish from reaching the lakes outweigh the states’ demand for immediate relief. The court added that if the agencies’ efforts “slip into somnolence” or if new information surfaces at the permanent injunction stage, the ruling would be reconsidered. Asian carp can grow up to 100 pounds and, according to the states, could wipe out the region’s $7 billion commercial fishing industry and imperil the recreational boating sector. Native to China and with no known predators in the United States, Asian carp have overwhelmed native fish populations by outcompeting them for food. See Chicago Tribune, August 25, 2011.