Local News

Great white sharks are flocking to this island off Chatham

This year, several Cape Cod sharks are summering off South Monomoy Island.

This screenshot from the Sharktivity app shows shark encounters near Chatham.

August 23, 2025

1 minute to read

Last week, more than half of Cape Cod’s great white shark sightings were concentrated near an island off the coast of Chatham, according to a local organization that tracks shark activity.

Since Aug. 14, the Atlantic White Shark Conservancy has reported 20 shark encounters and one seal attack, which were tracked on the group’s Sharktivity app. However, one area in particular is seeing a lot of action—South Monomoy Island. Since the start of August, there have been nearly two dozen reports of great white sharks spotted within a few hundred yards off the island.

Activity ramped up last week, with 11 white sharks reported there between Aug. 15 and Aug. 17. One shark was seen there on Aug. 15, another five on Aug. 16, and five more on Aug. 17, according to the app. Sharktivity users reported that most sharks swam between 50 and 100 yards off the island’s eastern side, with some heading into northern waters.

The Chatham-based conservancy routinely tags and names the sharks that visit the Cape’s shoreline. Each tag then transmits real-time data that feeds directly into the Sharktivity app.

The conservancy recently highlighted one male shark, dubbed Quadrilateral, who has made several appearances this summer. One recording showed him near Nauset Beach on Aug. 14.

“Quadrilateral” is an 11-foot, male white shark that was originally identified in 2017 and was tagged in 2023. The four freckles behind the right gills look like a quadrilateral,” the group wrote of the shark.

According to the conservancy, the only recent sign of shark predation on Cape Cod involved a seal near Nauset Beach North in Orleans around noon on Aug. 16. A comment featuring a photo in the app stated, “Seal on sand bar with what looks to be a bite mark. Still alive, but struggling.”