University of New England students Clayton Nyiri, left, and Ben LaFreniere deploy a buoy with Assistant Professor John Mohan, seen behind Nyiri, in Saco Bay off Saco and Old Orchard Beach on Tuesday. Gregory Rec/Staff Photographer

The first buoy of its kind to be used in Maine, which sends real-time notifications when a tagged white shark swims nearby, was deployed in Saco Bay on Tuesday.

It is one of two buoys of this type to be placed in Maine coastal waters to alert researchers and beach lifeguards when a white shark is in the area.

“What’s unique about this system is that it operates in real time,” said John Mohan, assistant professor at the University of New England. “We want to make sure that if there are tagged sharks in the water, the lifeguards can be notified and the flags can go up.”

Mohan said the effort was motivated by the Maine White Shark Working Group, a grassroots organization that formed after the fatal shark attack in Harpswell in 2020 that killed Julie Dimperio Holowach. The group is comprised of researchers, lifeguards and coastal community members. “Lifeguards wanted to know, ‘What can we do to be prepared?’ ” Mohan said.

About 270 white sharks have been tagged by the Atlantic White Shark Conservancy and Massachusetts Marine Fisheries, and this same notification system has been used successfully off Cape Cod. White sharks can travel great distances and it is not uncommon for them to travel into the Gulf of Maine in search of seals, one of their favorite foods. With the seal population rebounding all along the coast, Mohan said, it makes sense that researchers are seeing a higher incidence of white sharks in Maine waters.

“White sharks are top predators, so they feed on seals,” he said. “More seals means more sharks.”


The small yellow buoy sits about 2 feet out of the water near the Saco and Old Orchard Beach beaches. It has three solar panels on top to power the GPS and cellular systems, which transmit out a notification when a tagged shark swims nearby.

Matthew Davis of the Maine Department of Marine Resources, who was assisting with the buoy deployment Tuesday, said that when the alerts are triggered, it sends an email to researchers as well as beach officials in the area. The second buoy, which will be placed near Popham Beach, will be put in the water by the DMR in a few weeks.

The alerts generated by the two buoys are part of a larger research effort to study white sharks in Maine waters. There are 32 passive acoustic receivers in near-shore locations from York to Boothbay Harbor that record the presence of tagged white sharks. But unlike the two new buoys, those receivers don’t transmit their data in real time. Researchers must gather the receivers and download their data.

Mohan said the buoys are also part of a public education effort. “These are sharks’ homes and they naturally occur here,” he said. “We want them to understand that sharks are in these waters and they have been for a long time.”

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