US Army Corps plans ‘zone of chaos’ to keep invasive carp from reaching Great Lakes

CLEVELAND, Ohio — The U.S. Army Corps of Engineers has planned an aquatic house of horrors for invasive Asian carp threatening the Great Lakes.

The chafe gauntlet is part of a “layered defence” of Lake Michigan that the Corps is preparing to implement over the next few years to thwart the arrival of unwanted carp through the area’s rivers and canals. from Chicago.

If noise won’t chase them away, then maybe the bubble curtain will. And if neither succeeds, then ideally a blow of electricity will do.

The plan received a boost last week when the Biden administration awarded $225.8 million for the partial design and construction of the Brandon Road Interbasin project, which comes with an ultimate price tag of more than $850. million dollars over several years.

The Corps hopes to award a construction contract for “increment one” in the summer of 2024.

fish of concern

There are four main species of Asian carp that cause concern to the Corps and others concerned with the health of the Great Lakes.

Silver carp and bighead carp are thought to be the two most destructive in Lake Erie, said Tory Gabriel, extension program manager and fisheries educator for the Ohio Sea Grant program at Ohio State University. This is because they eat plankton and would crowd out native species like walleye and perch.

Silver carp pose an additional danger as they are known to jump out of the water in response to boat engines and cause injury to humans.

Great Lakes advocates have feared for years that Asian carp are moving from the Mississippi watershed into Lake Michigan, threatening the entire Great Lakes and its multi-billion dollar fishing and shipping industries.

A 2011 USGS photo showing an invasive silver carp leaping out of the water.

Connecting watersheds

The Carp Lane was created over a century ago after Chicago became concerned about sewage flowing from the Chicago River into Lake Michigan and reversed the course of the river so that it instead connects to the Des Plaines River, which is part of the Mississippi River Basin.

A similar Calumet River diversion is also part of the extensive network of waterways west of Chicago.

So far, only one silver carp has been caught upstream of existing electrical barriers located in the village of Romeoville on the Chicago Sanitary and Ship Canal, said Kevin Irons, deputy chief of fisheries for the Illinois Department of Natural Resources. . It was 2017, about nine miles west of Lake Michigan on the Little Calumet River.

“It’s rather strange that he appeared where he is,” Irons said, adding that he could have been pulled through the electric barriers by a barge “or a human could have put him in a bucket. and take him there.”

A single bighead carp was found in Lake Calumet, which is also part of the river system, in 2010.

invasive carp status map

Invasive Carp Status Map

What does the carp have in store?

The Interbasin project, which is planned for the Brandon Road lock and dam 27 miles southwest of Chicago on the Des Plaines River, would provide additional safeguards to prevent carp from reaching even existing electrical barriers in Romeoville. .

One of the planned deterrents will be in-water speakers that will emit a noise designed to scare fish away. Irons said researchers are still working on the right sounds.

“We know we could poke the fish with boat engine noises,” he said, but blasting them might be ineffective because those are probably just certain frequencies that the fish respond to.

“It won’t be music or scripted sound,” he said, but probably something closer to white noise.

A second layer of deterrent will be a bubble curtain rising from an air filled pipe along the bottom of the stream. The bubbles are expected to deflect fish, said Corps project manager Andrew Leichty, but they can also be used to extract tiny carp caught in the hydraulic currents created between two barges as they approach the lock.

In addition, an electric barrier will be installed as part of the “second phase” of the project. It is expected to be more effective on larger carp.

Among the safety issues with an electrical barrier are stray voltage that can interfere with nearby electrical systems and humans falling from boats and into charged water, Leichty said.

In Romeoville, all sailors must be inside their ship’s wheelhouse when passing through the electrified area as a precaution against falling overboard, Leichty said.

Yet another technique that will be employed later in the development of the project will be the ability to flush water downstream through the lock as ships pass. The flush would be designed to wash away any fish eggs or larvae floating in the water, Leichty said.

A price on their heads

Additionally, as part of a comprehensive interagency front to combat carp, the Illinois Department of Natural Resources will continue to encourage anglers to catch and remove the offending species from Illinois rivers to that they never reach the Chicago area. There’s a $100 per fish premium on black carp, which is the hardest to find of the four, Irons said.

Additionally, anglers can earn 10 cents for every pound of Asian carp they catch along an 80-mile stretch of the Illinois River, which is formed by the confluence of the Des Plaines and Kankakee Rivers and empties into the Mississippi.

Right now, most carp don’t swim very far up the Des Plaines River, Irons said, and one reason could be that they’re disabled by pollutants, including discarded chemicals and drugs. , which they encounter in the water when they go upstream. Chicago.

While Asian carp can damage all of the Great Lakes, Lake Erie could be particularly damaged by Asian carp, according to a 2016 report from the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory.

The only one of the four species found in Lake Erie so far is grass carp. It was first detected spawning in the Sandusky River in 2013 and likely arrived there after being stocked in ponds years ago, Gabriel said.

Grass carp are considered less harmful than silver or bighead species because they feed on aquatic vegetation, Gabriel said, and so far have not been found in populations large enough to cause harm. .

Three bighead carp have been found in Lake Erie, one in 1995 and two in 2000, while silver carp have never been seen in the lake, Gabriel said.

Gabriel said he supports the Brandon Road Interbasin project, which would essentially create a “zone of chaos” that fish would have to cross to reach Lake Michigan.

When asked if he was confident the efforts would be able to keep Asian carp at bay, Gabriel said it was hard to say.

“The more we do things like this, the more my confidence increases,” he said.

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