Updated July 29, 2026 at 3:00 PM EDT
You may notice some new visitors during your next beach trip to Cape Cod.
“We’re definitely seeing some shark species that I would say aren’t typical for the neighborhood,” said Ryan Knotek, a research scientist with the Anderson Cabot Center for Ocean Life at the New England Aquarium.
Spinner, tiger and smooth hammerhead sharks have all been spotted either by research teams or by members of the public off the coast of New England this year and in the past few years. They’re likely here because of climate change, Knotek said.
All three are cold-blooded species, so they depend on outside sources to regulate their body temperature.
“They kind of have to stay in waters that work for their bodies, the temperatures that work for their bodies,” he said.
New England’s coastlines were considered the upper limit of their territories, according to Knotek. But that may be changing.
“They have a limit where it’s too cold for them, and then they have a limit where it’s too hot,” he said. “And with climate change here in the Northern Hemisphere, that limit where it’s too cold for a lot of these shark species, it’s shifting further and further north as we see seawater temperatures rise.”
Ocean temps in the North Atlantic are some of the highest ever recorded, according to data from the University of Maine’s Climate Change Institute. And data from 2019 showed New England waters were warming more than anywhere else in the country.
It’s not just the warmer water that’s made New England’s coast a draw. The ocean in the region is cleaner than it used to be.
“Boston Harbor is an example of it’s cleaned up and it’s an area where they get to and they’re like, ‘OK, this is an area that we can stay,’ ” Knotek said.
The newcomers join an established ecosystem of shark species like the shortfin, mako, porbeagle, thresher and great white. But Knotek said we should expect to see more unexpected species in the coming years as waters continue to warm.
“I would look more at some of the species that are showing up just south of New England, and I would say that those are the ones that we would expect next,” he said, listing blacktips and bullsharks as potential future visitors.
Knotek said the newly arrived visitors will likely stay for a few months, typically off shore in deeper waters, and return south by the fall.
While there may be more sharks in the waters near the region’s beaches, Knotek suggested some common sense protections for beach goers.
“We’re never on the menu” for sharks, he said, but cautious bathers should avoid swimming at dawn and dusk — feeding time for sharks. You can also leave flashy jewelry or clothes on shore, if you can.
This article was originally published on WBUR.org.
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