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Shark spotted off South Beach in Chatham

Passengers gasped and screamed as they spotted a great white shark swimming under their boat off of Chatham Thursday afternoon, according to video footage provided by the Atlantic White Shark Conservancy.

The giant marine predator, a male estimated at 15 feet long, was meandering along the coast of South Beach in Chatham moving through the clear, turquoise waters under a boat with a family onboard. After seeing the video shot by the family, the conservancy sent out a spotter pilot and vessel to film the aquatic hunter below the waves. The video was shot with a GoPro camera by scientist John Chisholm, who is working on a shark population study.

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Thursday’s sighting, dramatic as it was, is one of many off the Cape Cod coastlines, said researchers. Greg Skomal, a biologist with the state Division of Marine Fisheries, said he would ballpark the sightings this year at “well over a dozen.”

In June, researchers with the conservancy tracked a 14-foot-long female shark through Orleans waters, about a quarter-mile from Nauset Beach.

Earlier this month, researchers tagged their first great white shark of the season to track and study the briny carnivore. The tagged shark, nicknamed “Avery,” was around 12 feet long and marked by the Massachusetts Shark Research Program off of Chatham. The shark spotted on Thursday was not tagged, said the conservancy in a Facebook comment.

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The Atlantic White Shark Conservancy, a nonprofit volunteer organization, will continue to look for sharks through mid-October all along the eastern coast of the Cape.

A study published by the National Oceanic and Atmospheric Administration in June said that the great white shark population has grown in the western North Atlantic waters. The study attributed the boost to conservation efforts for both sharks and their prey. Seals, which has also seen a significant jump in population, are a major pull for sharks spotted in local areas.

Derek J. Anderson can be reached at derek.anderson@globe.com.
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