(Bloomberg Businessweek) -- Standing on a windy bridge over the Des Plaines River in Joliet, Illinois, Scott Whitney shows off a diagram of what he calls the gauntlet. Pictured is a half-mile-long underwater obstacle course for fish that runs upstream toward Lake Michigan. A curtain of turbulent bubbles is followed by a bank of speakers emitting ear-splitting noise, then a wall of electrified water and finally a navigation lock designed to flush downstream any organisms that make it that far. “It’s hell for the fish,” says Whitney, chief of the project management branch for the US Army Corps of Engineers’ Rock Island District.
He’s focused on one in particular: invasive carp, which have menaced Midwest rivers for decades. Whitney’s gauntlet—officially known as the Brandon Road Interbasin Project at the Brandon Road Lock and Dam—aims to stop the carp from getting any closer to Lake Michigan. Scientists deem this spot the fish’s likeliest entry point into the Great Lakes and its fishing industry, which the Great Lakes Fishery Commission values at $5.1 billion annually. The Corps plans to start building the BRIP in January at a cost of $1.15 billion, with Illinois, Michigan and the federal government splitting the tab.
The barrier will be the most ambitious defense against the carp in America. Their deep hunger for plankton has wreaked havoc on ecosystems, effectively pushing out native fish throughout the Mississippi and its tributaries. In addition to screwing with the food chain, the carp are despised by fishermen. Silver carp—one of four closely related species native to different parts of Asia—sometimes leap into the air at the sound of an outboard motor, a stress reaction that has knocked anglers unconscious and shattered facial bones.
Already, state and federal governments have poured hundreds of millions of dollars into control measures, including electric barriers, harvesting programs and even campaigns aimed at chefs and home cooks. But none will attempt to seal off the carp’s potential passage into the Great Lakes with this level of investment. “There really is no other project, probably in the history of humankind, that has put so much time, money and effort into trying to curb the movement of an invasive species,” says Jim Garvey, a professor of zoology and director of the Center for Fisheries, Aquaculture and Aquatic Sciences at Southern Illinois University.
The US’s struggle against invasive carp started with a well-meaning blunder, as journalist Dan Egan writes in The Death and Life of the Great Lakes. In the 1970s government scientists in Arkansas were testing to see if carp imported from Asia could, as an alternative to chemicals, clean up algae from catfish farms and sewage lagoons. Eventually funding ran out, and the research stopped. But some of the experimental fish were released, finding their way into surrounding waterways. The scientists thought the fish wouldn’t breed in the wild. They were wrong.
As they’ve migrated up the Mississippi River basin, two species have had a particularly suffocating effect. Silver and bighead carp can live for decades, eating pounds of plankton every day. Studies have found silver carp make up more than 90% of the aquatic biomass in sections of the Mississippi.
In 2002, as part of a broader congressional effort to control invasive aquatic species, the Army Corps installed its first electric barrier to fend off non-native fish in the Chicago Ship and Sanitary Canal, the critical connection point between the Mississippi basin and the Great Lakes. In a section of the canal in Romeoville, Illinois, about 10 miles upriver from Brandon Road, an underwater carpet of electrodes emits an electrical field designed to deter carp that swim near it. Over the past two decades, the Corps has spent about $286 million adding similar barriers in Romeoville and tweaking their voltage levels.
How effective these have been is a topic of controversy. No carp has been documented passing through them. But a handful of carp and a lot of their DNA have been found upstream of the barriers, close to Lake Michigan. After one DNA discovery in 2009, Michigan sued the Corps and Illinois, demanding the canal be closed because of the carp’s threat to Great Lakes fisheries. Such a closure would’ve blocked the small amount of barge traffic that uses the canal to travel in and out of Lake Michigan and forced Chicago to rethink its wastewater disposal. Debate raged over what closure would cost: The Corps pegged it at $18 billion; advocacy groups put it closer to $2 billion.
The case wound its way to the Supreme Court, which eventually rejected the closure request. But the sense of emergency was real. “‘Terminator’ carp threatens Great Lakes,” the Guardian proclaimed in 2010. Then-President Barack Obama nominated a carp czar to oversee eradication efforts.
Amid the Great Carp Alarm, Congress directed the Corps to study additional options to prevent invasive species from spreading between the Mississippi basin and the Great Lakes. In 2019 the chief of the Corps signed off on the Brandon Road project. Its deterrents are crafted to target carp at different life stages, Whitney says.
Since most of the project is underwater, the view from the bridge where Whitney is showing off the plan won’t be that different when the BRIP is complete. The changes will be below the surface: The channel is being reconstructed to eliminate fish hiding spots or food sources and to shore up the structural integrity of the 91-year-old navigation facility. The plan is to install the BRIP’s electrical barriers with superior insulation to the ones operating in Romeoville, which have been known to throw out stray voltage. The noise from the underwater speakers will sound a little like a fork caught in a lawn mower.
Biologists are optimistic that the BRIP will keep carp at bay. And, really, it’s designed to be redundant with the setup in Romeoville, which will continue to operate at a cost of about $15 million per year. Illinois also spends more than $2.5 million a year paying fishermen to pull millions of pounds of carp out of the rivers. (In 2022 the state led a campaign to persuade chefs to put carp on restaurant menus, rebranding it “copi,” short for copious, but it hasn’t caught on.) “There is no single thing that anyone can do to make it a surefire” deterrent, says Reuben Keller, a professor of environmental science at Loyola University Chicago who studies aquatic invasion ecology.
Definitions of success may vary. The goal of the BRIP is to stop carp to the greatest extent possible, but there’s no official key performance indicator. Whitney acknowledges that, over time, carp could adapt to the BRIP’s deterrents and swim past them. That’s why he considers the project an example of “adaptive management,” meaning the Corps will continue to develop and add anti-carp defenses as necessary. “It’s the best we can do today,” Whitney says, “to prevent disastrous consequences if we fail.”
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