July 28, 2026.
The battle to protect the Great Lakes from one of North America's most destructive invasive fish species has entered a critical new phase as construction continues on an ambitious system of barriers designed to stop invasive carp before they can reach Lake Michigan.
Often referred to as "Asian carp," the invasive fish—including silver, bighead, black and grass carp—were imported into the United States during the 1970s to help control algae and aquatic vegetation in southern fish farms. Flooding allowed many of the fish to escape into the Mississippi River basin, where they spread rapidly throughout connected waterways.
Biologists warn that if self-sustaining populations become established in the Great Lakes, they could dramatically alter one of the world's largest freshwater ecosystems.
Silver and bighead carp consume enormous amounts of plankton, the foundation of the aquatic food web. By competing with native fish for food, the invasive species could threaten populations of yellow perch, walleye, lake whitefish and other commercially and recreationally valuable fish.
The Great Lakes support a fishing industry worth billions of dollars annually and provide drinking water for more than 40 million people in the United States and Canada. Officials say preventing invasive carp from entering the lakes remains far less expensive than attempting to control them after establishment.
Brandon Road Project
The centerpiece of the prevention effort is the Brandon Road Interbasin Project near Joliet, Illinois, where the Illinois Waterway narrows before connecting toward Lake Michigan.
The location has been identified by federal scientists as the most effective place to block upstream movement of invasive carp from the Mississippi River basin into the Great Lakes.
Rather than relying on a single barrier, engineers are building a layered defense system that includes:
- Electric deterrent fields
- Bubble curtain technology
- Underwater acoustic deterrents
- Flushing systems that create powerful water currents
- Automated barge-clearing technology
- Engineered channels designed to discourage fish movement
The existing electric dispersal barrier farther downstream near Romeoville will continue operating alongside the new system, creating multiple lines of defense.
Construction Moving Forward
Construction officially entered its next phase this year after the U.S. Army Corps of Engineers transferred project management to its Detroit District and awarded another major construction contract.
The latest contract, valued at approximately $113.8 million, will install many of the project's leading-edge deterrent technologies, including the bubble curtain, acoustic system and automated barge-clearing equipment.
Overall, the Brandon Road project is expected to cost about $1.15 billion and will be completed in multiple construction phases over the coming years.
Constant Monitoring
While no reproducing population of invasive carp has become established in the Great Lakes, state, federal and Canadian agencies continue extensive monitoring throughout the region.
Scientists regularly collect environmental DNA (eDNA) samples, conduct electrofishing surveys, deploy commercial fishing crews, and monitor waterways connected to the Great Lakes to detect any signs of invasive carp before populations become established.
Commercial harvest programs in the Illinois River are also removing thousands of invasive carp annually in an effort to reduce the number of fish moving north toward the Great Lakes.
A Race Against Time
Environmental organizations and fisheries managers describe the Brandon Road project as one of the most important aquatic invasive species prevention efforts ever undertaken in North America.
Unlike many invasive species that can only be managed after becoming established, officials believe the Great Lakes still have an opportunity to prevent invasive carp from gaining a permanent foothold.
"The goal is simple," officials say. "Keep the fish out before they arrive."
If successful, the combination of physical barriers, electric fields, sound deterrents and ongoing monitoring could protect the Great Lakes ecosystem—and the communities and industries that depend upon it—for generations.