Scientists watching for more dusky shark sightings off the coast of Nantucket following 2025 seal attacks
Skomal said scientists will continue monitoring for dusky shark behavior as we head into mid to late summer.
Video shows dusky sharks preying on seal off Nantucket, Massachusetts
A new study from the Atlantic White Shark Conservancy reveals video from July 2023 of what is believed to be the first direct observation of dusky sharks preying on seals.
Scientists and researchers are on the lookout for dusky sharks off the coast of Massachusetts to see if they continue a pattern of behavior documented last year that had never been seen before.
In 2025, it was discovered that a group of sharks found to be attacking and eating seals off the coast of Nantucket were dusky sharks, after previously thinking it had been white sharks killing the seals, a common behavior for the white shark species.
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The discovery marked a massive milestone for marine fisheries scientists, who are now hoping to witness the behavior again and document it for further research.
Dusky shark (Carcharhinus obscurus).
(HUM Images/Universal Images Group / Getty Images)
Greg Skomal, fisheries biologist with the Massachusetts Division of Marine Fisheries, said it's too early in the season so far to witness these sharks this far north in New England, as the summer migratory season just gets underway.
"The discovery here has more to do with the fact that we've been able to observe this species attacking, killing and eating seals," Skomal said. "And that has never been described before in the dusky shark anywhere in the world."
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Skomal said dusky sharks are long known to eat several types of fish, but never seals, and it's probably not a new pattern of behavior for the shark.
A dusky shark seen hunting off Southampton, New York on July 20, 2024.
(Joanna Steidle via Storyful / FOX Weather)
The dusky shark was highly overfished in the 80s and 90s, and as a result the population has seen a decline. It's not officially endangered, but Skomal said it's prohibited to be caught, sold or eaten.
"There's very few species of sharks on the planet that can target seals and sea lions," Skomal said. "It takes strength, power, speed, agility, you name it. It's a challenging prey species."
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Because of this, he said there aren't that many predators of seals and sea lions. White sharks, tiger sharks, in some cases, Galápagos sharks and Orcas, are known to target seals.
Skomal said scientists' goal now is to try and pin down what happens during these predatory events.
Dusky shark
(OCEARCH)
"Number one, it's of huge public safety interest in that area (Cape Cod)," he said.
The same advice is given to those visiting and swimming near Cape Cod as in other areas with shark activity: be careful because there are large predatory sharks eating their prey.
He said they also want to better understand how often this happens and many of the other schematics behind a discovery like this.
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Photo shows a dusky shark chasing a grey seal off the coast of Nantucket in July 2023.
(Atlantic White Shark Conservancy / FOX Weather)
Scientists are asking questions like:
- Is it the same group of sharks preying on seals in this area?
- How many are there?
- Is it group feeding or is it solitary feeding behavior?
- When does it end? Is it a seasonal occurrence?
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"These are really basic questions that'll help us better understand the biology of the species, but also to give advice to the public regarding public safety."
Skomal said beachgoers should be mindful and don't want to swim in areas with a large population of seals.
"Those seals are going to draw the attention of these two species," he said. "In this case, it would draw the attention of white sharks along the eastward-facing beaches of the Cape, and it'll draw the attention of dusky sharks along the eastern beaches of Nantucket."
A sign where a shark was spotted along South Beach in Martha's Vineyard. Friday, July 11, 2008.
(Stuart Cahill/MediaNews Group/Boston Herald / Getty Images)
When heading to the beach, look for life. Skomal said breaking schools of fish, bird activity on the water and seals will draw predators' attention.
"My advice is you don't swim out into those areas," he said. "It's kind of a general rule for folks who are concerned about their safety and concerned about sharks while at the same time acknowledging the probability of being bitten by a shark is still extremely low."
Skomal said scientists will continue monitoring for dusky shark behavior as we head into mid to late summer.