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States build a roadblock for invasive carp

As threats go, this one is considered imminent. While no live bighead, silver, or black carp have been found in the Great Lakes, there is no question, given their ongoing spread in the Mississippi River basin, that these invasive fish would thrive in the Great Lakes region, particularly in places such as Saginaw Bay and Lake Erie and the mouths of rivers such as the St. Joseph or the Grand. 

Silver carp in the Illinois River jump in reaction to electrofishing. Photo courtesy of U.S. Fish and Wildlife Service.

Silver carp in the Illinois River jump in reaction to electrofishing. Photo courtesy of U.S. Fish and Wildlife Service.  


On July 1, Governor Gretchen Whitmer announced that Michigan signed an agreement with the U.S. Army Corps of Engineers and the State of Illinois to cosponsor construction of the Brandon Road Interbasin Project near Joliet, Illinois, to stop the advance of these invasive fish. The milestone agreement with the Biden Administration unlocks $274 million in federal funding and $114 million in state funding for the first of three phases of the $1.15 billion project to protect the Great Lakes.

“Today’s agreement will help us get shovels in the ground as soon as possible on the critical Brandon Road project,” Governor Whitmer said. “The Great Lakes are the beating heart of Michigan’s economy, and Brandon Road will help us protect local communities and key industries, including fishing and boating, that support tens of thousands of good-paying jobs. I am grateful to Governor [J.B.] Pritzker in Illinois, the Army Corps of Engineers, and our champions in Congress for their long-term partnership on this monumental task. Together, we will get the job done so we can protect our lakes and power economic growth for generations to come."

A risk assessment by the U.S., Canada, and the Great Lakes Fishery Commission says as few as 10 male and 10 female carp in the Great Lakes could provide a reproducing population. The report concluded that the point of greatest risk for invasive carp to enter the Great Lakes is the Chicago Area Waterway System. 

Up to now, a series of three electric barriers has been the last line of defense between the carp and the Great Lakes.

Brandon Road Lock and Dam plans call for a system of structural and nonstructural control measures at a critical pinch point for keeping invasive carp out of the lakes. 

About the invaders 

Bighead and silver carp are long-lived fish that reproduce prolifically and can grow to nearly 100 pounds, filtering plankton out of the water column and eating larval fish. Due to their size and abundance, bighead and silver carp compete directly with native species, particularly in young life stages.  

Each year, the U.S. Fish and Wildlife Service conducts environmental DNA (eDNA) sampling to look for evidence of invasive carp in drowned river mouths and rivers throughout the Great Lakes. In Michigan, they look in “carpy” type habitats in Lake Michigan and Lake Huron. This surveillance is part of early detection that would allow fisheries managers to respond.  

In places where invasive carp abound, local fish communities and recreational opportunities suffer. Invasive carp could significantly alter the Great Lakes ecosystem, affecting the $7 billion fishery, $16 billion boating industry, other tourism-based industries, property owners, recreationalists, and others dependent on the Great Lakes and their tributaries.  

About the roadblock 

The Brandon Road project includes several technologies – an electric barrier, underwater sound, an air bubble curtain, a flushing lock, and more – in a newly engineered channel designed to prevent invasive carp movement while allowing barges to continue to move through the Chicago Area Waterway System.

Supporting Illinois’ role as nonfederal sponsor, Michigan committed an initial $8 million to project engineering and design. The Michigan Department of Natural Resources (DNR) has participated for three years in design discussions and is part of the process to ensure this critical project provides the most efficient and effective approach to protect the Great Lakes and inland waters in Michigan.  

Joining the battle  

Michigan’s experiences with invasive aquatic species prove that prevention is far more effective and less expensive than trying to manage them in the Great Lakes.  

The DNR and the Michigan Department of Environment, Great Lakes, and Energy call upon Michiganders to be vigilant and help in the efforts to keep invasive carp out of our state’s waterways by reporting unusual fish and knowing bait species. Materials are available to assist in identification, and an online reporting system is available at  

Adapted from an article in the 2023 Michigan State of the Great Lakes Report by Tammy Newcomb, Michigan Department of Natural Resources.