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Real-time shark detection devices deployed in Maine waters

John A. Mohan, assistant professor at the University of New England, (standing on left) worked with Matthew Davis of the Maine Department of Marine Resources (right) to deploy a real-time shark detection system into Saco Bay on Tuesday.University of New England

Two shark detection receivers are being deployed in Maine waters to monitor the presence of tagged white sharks in real time.

One receiver was deployed in Saco Bay last week and a second one will be deployed at Popham Beach “in the next week or two,” said Matthew Davis, a marine scientist at the Maine Department of Marine Resources.

Whenever a tagged white shark swims within the range of these two receivers, authorities will be notified right away. The location of the shark will also be sent to the Atlantic White Shark Conservancy’s Sharktivity app, which monitors shark sightings and displays them on a map.


“This is the first time we have these in Maine,” said Davis.

There are other acoustic monitoring devices off the coast of Maine that track the movements of tagged sharks, but they collect data over the long term, and can’t provide information in real time. The receivers in Saco Bay and Popham Beach are the first ones that will detect tagged sharks in real time and send out alerts to authorities in a timely manner.

“These are a much more useful tool for public safety and awareness,” said Davis.

Shark monitoring efforts in Maine have increased since the death of Julie Dimperio Holowach, a 63-year-old seasonal resident of Harpswell, who died after she was bitten by a great white shark while swimming off of Bailey Island in July 2020. It was the state’s first fatal shark attack on record.

Davis said the two live receivers are being used in Saco Bay and Popham Beach because they are both areas that draw a large number of summer visitors.

Each receiver is attached to a buoy with solar panels and can send out a notification within minutes of a tagged white shark being detected.


“What’s unique is that this is real time...it allows lifeguards and first responders to be ready,” said John A. Mohan, assistant professor at the University of New England.

Mohan and Davis went out and deployed the first live receiver in Saco Bay on Tuesday. It was placed within 1,000 meters of the shore in a spot where the water is 27 feet deep, Mohan said.

It will be able to detect tagged sharks that swim within 500 to 700 meters of it, Mohan said.

Mohan said the two live receivers will also help raise public awareness about the presence of white sharks in Maine waters.

“It’s also an educational tool, in addition to a safety measure,” said Mohan.

Davis also noted that the receivers can only detect sharks that have been tagged. If any other shark happens to roam into the area, it won’t be detected by the system.

“These live receivers are only going to pick up ones with a tag on them,” Davis said. “It’s important people are aware of this, so there’s not a false sense of security here.”

Emily Sweeney can be reached at emily.sweeney@globe.com. Follow her @emilysweeney and on Instagram @emilysweeney22.