New Bubble Barrier to Repel Asian Carp?

The Asian carp is threatening to invade the Great Lakes. Right now there’s an electric barrier in the Chicago canal to stop the fish from getting into Lake Michigan, but a new study shows it’s not 100-percent effective. As the Great Lakes Radio Consortium’s Annie Macdowell reports, scientists are working on a second line of defense…bubbles:

Transcript

The Asian carp is threatening to invade the Great Lakes. Right now there’s an
electric barrier in the Chicago canal to stop the fish from getting into Lake
Michigan, but a new study shows it’s not 100% effective. As the Great Lakes
Radio Consortium’s Annie Macdowell reports, scientists are working on a second
line of defense – bubbles.


In a recent experiment by the Illinois Natural History Survey, a startled Asian
carp swam straight through an electric field like the one in the Chicago Canal.


The International Joint Commission is bringing specialists from Britain to build
an experimental acoustic bubble barrier and test it on the Asian carp. It works
like this: a pump filled with air and sound expels bubbles with sound trapped
inside.


Bill Moy of the Wisconsin Sea Grant says the process creates a nearly seamless
barrier.


“If you just project sound into the water, it’s not like a wall of sound. But by
entraining the sound in this bubble, you can actually create a wall of sound in
the water that’s much more uniform.”

Moy says the infrasound inside the bubbles is like an idling truck – you can feel it
more than you hear it.


The fish can’t find a break in the sound, so they turn around.


The International Joint Commission says if they decide to install the bubble
barrier, it won’t be until the spring.


For the Great Lakes Radio Consortium, I’m Annie MacDowell.