BOSTON — A plan to develop an acoustic system to chase away seals in order to prevent shark attacks is the latest front in the debate about how Cape Cod should respond in the wake of last year’s shark attacks.
Deep Blue LLC presented the idea for an “invisible fence” to the Barnstable County Commissioners on Wednesday, drawing support from some officials and residents but concern from local animal rights groups.
Company owner Willy Planinshek envisions a system of underwater audio devices set up at the region’s most popular swimming beaches. The devices would be mounted on buoys some distance from the shore and emit a sound unpleasant to seals but inaudible to humans.
Planinshek believes that if seals are discouraged from the areas, the great white sharks that feast on them will also stay away.
“We’re creating an invisible fence like what use to keep your dog on your property,” he said. “Except in this case, we’re keeping other dogs out of the yard.”
Commission members applauded the idea as a “proactive rather than reactive” solution, echoing a common criticism of shark safety proposals so far adopted by local officials. They asked the company to return in the fall to give an update on their progress developing the system.
“Anything that would give the public more confidence in our beaches is important to us,” said Commission Chair Ronald Bergstrom.
Two men were attacked — one fatally — by sharks off the Cape last summer.
Local animal rights activists said they support non-lethal solutions to the region’s concerns but cautioned that such acoustic deterrent systems have failed elsewhere.
Seals have been found to make simple adjustments to cope with the noise emitted by the underwater devices, such as swimming with their head above water, said Sharon Young, a Cape Cod resident and marine issues field director for the Humane Society of the United States.
The sound systems have also been found to negatively impact other species of marine life, said Brian Sharp, director of marine mammal rescue and research for the Cape Cod-based International Fund for Animal Welfare.
And it’s no guarantee the great white sharks will move on even if the seals leave, since the Cape’s waters also teem with other marine life the sharks favor, such as large fish and whales, Young and Sharp said.
“When public money is being spent, you should not be throwing good money after bad ideas,” Young said. “This is just reinventing a broken wheel.”
Planinshek disputed the notion that the sharks would remain even if seals left and said the system wouldn’t harm other marine life or humans. He stressed that his company isn’t seeking public funding to develop its idea.
Some local residents also said the activists for prioritizing seal and shark welfare over the safety of humans.
“The question here is: do seals still need to be protected? We have a law that’s been on the books for 50 years,” said resident John Kartsounis, referring to the federal Marine Mammal Protection Act on 1972. “Seals are not endangered, and neither are great whites.”
Cape officials could seek a narrow exemption to the federal law, as some states have done, suggested Commission member Ronald Beaty. In 2008, Washington, Oregon, and Idaho received federal authority to remove or kill sea lions preying on salmon and other protected fish species.
Cape Cod officials have invested in emergency call boxes, specially equipped beach medical kits and additional lifeguard training and other safety measures ahead of the summer beach season.
They’re also paying for an independent study on more costly and controversial steps, such as investing in shark barriers, aerial drones or seal culls.
That report, however, won’t be ready until the fall.
