High-Tech Acoustic Buoys Working to Make Coastal Areas Safer From Sharks

New England, especially Cape Cod, has had plenty of shark sightings this summer, and new technology is being used to alert beach visitors about increasing numbers of prowling coastal predators.

Great Whites off Cape Cod
New technology is helping biologists keep track of shark activity off the coast of New England this summer. NOAA

Cape Cod has been awash this summer with big sharks, including many massive great whites. State officials with the help of some other shark-interested groups are working to monitor the big predators, while also keeping beaches safer for visitors.

In one recent weekend, Cape Cod beach areas had 12 shark sighting reports, with some toothy predators seen just 50 yards off beaches. A new “Sharktivity App” is in use, allowing summer beach visitors to report shark sightings that alerts other people of predator presence.

But more technology is being used to monitor sharks.

The Massachusetts Division of Fisheries and Wildlife (MassWildlife) joined with the Atlantic White Shark Conservancy to set up two acoustic receiver buoys off Wellfleet beaches, located near the tip of Cape Code, southeast of Boston. One floating offshore buoy is near Newcome Hollow Beach, the other is in the Lecount Hollow-Maguire Landing beach areas.

Last summer buoys were deployed by the Atlantic White Shark Conservancy all across the Cape coastline. But the Wellfleet buoys are new this summer. The acoustic buoys detect sharks that are fitted with transmitters that show their locations to acoustic receivers.

The number of white sharks detected off Cape Cod by acoustic receivers has risen for eight years in a row. Last year, 132 individual sharks were detected, up from just 11 in 2013, according to the Atlantic White Shark Conservancy.

“We tag more (sharks) every year, so that’s going to automatically lead to more detections,” shark biologist Greg Skomal told the New England News Collaborative (NENC). “We also expand our receiver array a little bit each year, or other researchers put receivers in, and we get their data.”

Skomal says white shark numbers have increased in recent years around Cape Cod, because the predators are coming to feast on increasing numbers of seals in the area.

Skomal is among a team of scientists that share shark data from 200 acoustic buoys deployed along the coasts. Only a few of the buoys provide real-time data because the technology is expensive, nearly $20,000 each.

Drone cameras also are being used by shark watchers to monitor the big predators along the coast. Drones cruise over beaches and compare images they gather with acoustic data. Drone cameras have limitations, however.

“Sometimes the water is so clear it looks like the Caribbean,” scientist Megan Winton, told NENC. “Other times it looks like chocolate milk, and you really can’t see anything. It’s a very dynamic area.”

Cape Cod’s modern shark obsession started in Sept. 2018 when a man was killed by a shark off Wellfleet. A month earlier another man was hit and seriously hurt by a shark near the Cape Cod town of Truro.

The Cape Cod area is sure to have human-shark encounters during the peak beach-visiting seasons of August, September and October, says Skomal.

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