White sharks are considered apex predators in the waters off the Cape and Islands. But scientists have confirmed that another species – dusky sharks – have also been hunting seals off Nantucket.
Megan Winton is senior scientist at the Atlantic White Shark Conservancy. She says scientists captured drone footage of dusky sharks attacking a gray seal, after reports came in from beachgoers and boaters.
"Nobody knew that dusky sharks ate seals, she said. "And so when we started to get reports from people who were on the beach off of Great Point, we reviewed those images, we reviewed the video footage, and we were like, oh my gosh, these aren't white sharks. Because we all assumed they were white sharks."
Cape Cod is considered the northern extent of the dusky shark’s range in the western North Atlantic. Winton said dusky sharks have been feeding off Nantucket’s Great Point for the past several years.
"We'd been getting sightings of large sharks in that area for a few years prior to 2023," she said. "But that was the first year we actually received photos and videos from the public that allowed us to determine that these weren't white sharks, that these were dusky sharks, and launched this whole investigation."
Winton was lead author of a study published last August that documents the first direct observations of dusky sharks preying on seals.
She says precautions for Nantucket beach-goers remain the same.
"It's very well established at this point that white sharks, and now we know dusky sharks, are coming here to feed on seals, and we know they hunt for them in shallow water close to shore," she said. "So when you go to the beach, pay attention to the lifeguard's messaging. You don't want to swim with shark food."
She noted both white and dusky sharks prey on seals as well as schools of fish near shore.
