Anglers and other boaters already know that silver carp don't like noise, and arguably that's not a good thing. That's because huge schools of these exotic fish go airborne as they flee the sounds of outboard engines, often damaging boaters and injuring people.
But this aversion to noise also could provide a silver lining in the quest to slow the spread of silver carp, according to scientists with the University of Minnesota-Duluth (UMD) and the U.S. Geological Survey (USGS).
“Our complex noise findings suggest that certain sounds could be used to divert silver carp away from strategic points on waterways or herd them into nets,” said Brooke Vetter, a UMD researcher and graduate student.
After placing speakers at the ends of outdoor concrete ponds, scientists tested carp response to pure sounds, which resemble a dial tone, and more complex noises. The fish quickly adjusted to the pure tones, never swimming away more than two consecutive times. But they continuously fled the more complex sounds.
Now researchers are testing complex noise as a way to control silver carp in the Illinois River.
“Silver carp threaten many waterways in the Great Lakes basin by competing with native species,” said USGS's Mark Gaikowski. “Understanding silver carp behavior is critical for determining effective techniques to minimize the ecological and economic damage of this invasive species."