The Volokh Conspiracy

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Invasive species

Army Corps Plans a "zone of chaos" to Protect Great Lakes from Asian Carp

The federal government is developing some unusual strategies to constrain this invasive species.


The U.S. Army Corps of Engineers is taking some innovative, and perhaps unusual, steps to keep Asian carp (the silver and bighead carp in particular) from infesting the Great Lakes. From a report on

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

The gauntlet of irritation is part of a "layered defense" of Lake Michigan that the Corps is preparing to implement over the next several years to thwart the arrival of undesirable carp by way of Chicago-area rivers and canals.

If the noise won't drive them away, then perhaps the curtain of bubbles will. And if neither are successful then ideally a shot of electricity will do the trick.

The first part of this effort was just awarded a $225 million grant, and the federal government will ultimately spend close to $1 billion on the effort.

Corps officials and scientists are concerned that the Asian carp would crowd out native species within the Great Lakes ecosystem, including walleye and perch (which would be a significant blow to fishing in the region). And then there's this: "The silver carp provide an added danger because they are known to jump out of the water in response to boat motors and cause injuries to humans." (I see the makings of a great B-movie here.)

As for what the project will entail, here's more from the report:

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

A second layer of deterrent will be a curtain of bubbles rising from an air-filled pipe along the bottom of the stream. It's expected that the bubbles will turn the fish away, said Andrew Leichty, project manager for the Corps, but they may also be used to extract tiny carp caught in the hydraulic currents created between two barges as they approach the lock.

Also, an electric barrier will be installed as part of the project's "increment two." It's expected to be most effective on larger carp. . . .

Yet another technique to be employed later in the project's development will be the ability to flush water downstream through the lock when boats pass through. The flushing would be designed to carry away any fish eggs or larvae floating in the water, Leichty said.

Concern about Asian carp is not new, but these efforts are. Nearly a decade ago Great Lakes states lost a legal effort to force the federal government to take more aggressive steps to stem the carp's spread, after trying to take their case to the Supreme Court.