Monday, June 7, 2021

Underwater sound bar being tested to block invasive fish

(Radio Iowa) - An experiment is underway at a Mississippi River to see if sound can keep invasive carp from moving through a lock and dam near Keokuk. US Geological Survey scientist Marybeth Brey says the device is called Acoustic Deterrent System. She says the system is essentially an underwater soundbar with 16 speakers that were installed in the lock approach of Lock 19. Co-researcher Christa Woodley says they studied the types of sound that the invasive carp don't like.

"And we took that information and then we created a frequency range and a decibel range that the animals would be more sensitive to. Once we established that -- we went into the lab and began testing a series of sound frequencies designed to get their reaction," Woodley says.

Woodley works at the U-S Army Engineer Research and Development Center. She describes the final sound they came up with as similar to the first few seconds of Motley Crue's "Kickstart My Heart."

"You know that really gritty sort of guitar VRRRR-like sound. That's what they kind of start out like and they are very effective. They hit low frequencies where they are very sensitive," she explains.

Brey says they had to outfit fish to test how the sound works.

"What we've been doing is putting acoustic transmitters in carp and in native fish to assess the behavior and movement through the lock approach," Brey explains.

It took a while to get all the fish ready, and Brey says they don't yet have scientific results they can share on the project.

"The only thing that I can say is we have seen carp in the approach when the sound is off, and we have not seen any visually when the sound is on," according to Brey. "That is not scientific whatsoever -- but that's about the best that we have right now."

She says they will know more later this year as they continue collecting information on the fish reaction. Brey says this could be a key help to their efforts to fight the invasive carp.

"A big goal is to keep fish out of the Great Lakes. So, I think there is some urgency there -- fish continue to move upstream," Brey says. "We have a lot of tools in our toolbox to remove fish...this would be another tool in our toolbox we are adding."

Other agencies involved in the research include the US Fish and Wildlife Service; the Illinois Department of Natural Resources; the Iowa DNR; the Minnesota DNR; the Missouri Department of Conservation and the Wisconsin DNR.

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