BARNSTABLE — Willy Planinshek and Kevin McCarthy proposed to the Barnstable County Commission on Wednesday an idea for an underwater sound system that would use noises, including killer whale vocalizations, to steer seals and scare sharks away from local beaches.

“We’re at the concept stage,” said Kevin McCarthy, who worked in management, marketing and sales at the Pocasset-based firm Hydroid, Teledyne Benthos and at the Woods Hole Group.

For now, their idea is just that. Studies and research have exposed flaws in the use of acoustic systems to deter sharks and other marine predators.

Planinshek and McCarthy have no funding, no prototype, nor any real research to back up their proposition of an invisible acoustic fence. But in an area hungry for ideas on how to reduce the risk of interactions between sharks and humans at the region’s ocean beaches, even a paper proposal gets a lot of attention.

The Commission’s tiny hearing room in the Barnstable County Courthouse was packed Wednesday with people and news cameras.

McCarthy noted that after the fatal shark attack on Revere bodyboarder Arthur Medici last fall, the commissioners asked the public for ideas, and that’s what he and Planinshek brought to them.

The proposal also has been submitted to the Woods Hole Group, which was analyzing deterrent, detection and barrier technologies, as well as other methods of shark and seal control, under a $50,000 contract with six Cape towns, the Cape Cod National Seashore and the Atlantic White Shark Conservancy. Many of those technologies are already in operation elsewhere and some are being or already have been tested for their effectiveness.

McCarthy and Planinshek hope to have a prototype operational by next year for testing in Cape waters.

Planinshek, a Yarmouth resident, said he and McCarthy would be using an ultrasound frequency pulse from an array of battery-powered buoys at beaches that he said he believed would prove annoying to seals.

“The seal will put on its blinker and take a right or left to deeper water,” Planinshek told commissioners.

But those sounds won’t discourage white sharks, whose hearing is tuned to different frequencies, from patrolling close to shore.

Planinshek and McCarthy said their system also will broadcast killer whale calls that, in theory, would frighten these massive predators. They quoted statistics from a recent study from Monterey Bay Aquarium, whose 27 years of data from 165 tagged great white sharks, combined with seal, orca and shark surveys, revealed that sharks, some as long as 18 feet, reacted immediately to the presence of orcas and left their preferred hunting grounds for as long as a year, even if killer whales were present for just a few hours.

Others argued that acoustic deterrent technology has a spotty track record. While it seems logical that killer whales would scare away white sharks, individual groups of orcas can be very specialized in what they eat, researchers say.

“It’s intriguing, but I would suspect it would not work at all,” University of Rhode Island doctoral student and marine mammal researcher Tara Stevens said of the use of orca calls as a shark deterrent.

“There is only one particular group [of whales] in the Pacific, on the West Coast, that is known to target and hunt great white sharks, and they have very specific feeding behaviors,” Stevens said. “On this coast we have not seen any interactions or heard reports of one.”

If great whites do not consider orcas a threat, a recording would not frighten them off, Stevens said.

Research and practical application of acoustic deterrents also have shown that most marine mammals quickly become habituated to sounds. Annoying noises, even explosive devices, have failed to discourage seals from taking fish from fishermen’s nets and from aquaculture operations, whales from stripping bait off longline hooks, or porpoises from entangling themselves in nets.

A 2014 Marine Scotland study reviewed various acoustic efforts and found that effectiveness always diminished over time. In Oregon, seals learned to swim with their heads above the water to avoid the noise.

“I have children. I want them to be safe,” said Sharon Young, marine issues field director for the Humane Society of the United States.

But given the long history of the ineffectiveness of acoustic deterrents, Young said, she felt there was no need to spend money on this project.

Still, Commissioner Ron Beaty did not immediately discount Planinshek and McCarthy’s idea Wednesday.

“The proposal they came up with today is not a be-all, end-all silver bullet, but it could be part of the puzzle,” Beaty said. “It’s a good start for a widespread, regional approach to the subject.”