Minnesota installing sound wall to fight off invasive flying carp

MINNEAPOLIS — You’ve likely seen video of flying carp — invasive, nuisance fish that can leap several feet out of the water. They’ve taken over a number of waterways in the U.S., and experts fear they’re getting close to Minnesota.
“Basically they got loose into the river and to everyone’s surprise have done extremely well,” said Dr. Peter Sorensen with the University of Minnesota.
Silver carp have made their way from Mississippi to Iowa and now they’re knocking on our door. As filter feeders they completely clean out ecosystems, diminishing other fish populations. But that’s not all. They can weigh up to 40 pounds and leap 9 feet out of the water
“If they hit you, I mean I have friends who have broken arms and collarbones and been knocked out of boats by these things,” said Sorensen.
Another reason why Sorensen is excited about a new tool that’s essentially a sound wall. It’s called a “BioAcoustic Fish Fence,” or BAFF. It uses bubbles to intensify sound, which scares away silver carp.
“We are the first state to proactively put one in before they arrived,” said Sorensen.          
Lawmakers approved $12 million for the project, and Sorensen believes the BAFF system has to be installed at Lock and Dam #5 in Minnesota City. That’s because the gates are hard for the fish to get through. Ideally, the sound wall would send the carp into a trap so they can be permanently removed.
“This is the least penetrable lock in the lower stretch of the Mississippi River in Minnesota,” said Sorensen. “This is the Alamo. This is the place you stop them and I sure hope we do it.”
The Minnesota Department of Natural Resources is working on plans to install the BAFF system. Sorensen says the silver carp are scared of high-frequency sound, but those frequencies don’t scare away walleyes or sturgeon.