Experts along the Cape Cod National Seashore are giving a warning to swimmers and surfers after Wednesday's shark attack off the coast of Truro, Massachusetts.
"Stay away from the seals, stay at least 150 feet away from seals," said Cape Cod National Seashore Superintendent Brian Carlstrom.
Sharks have been spotted several times this summer in the waters off Cape Cod.
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"They're following the seals," Carlstrom said. "Seals are their prey, that's their food source, and there's an interaction with people recreating."
After a shark bit and seriously injured 61-year-old William Lytton about 30 yards offshore on Long Nook Beach in Truro Wednesday, there's a renewed call for beachgoers to be aware that they are more than likely swimming relatively close to dangerous marine animals.
"Swim in groups, don't wear any shiny jewelry out there, it kind of looks like fish gills, make sure to recreate, get in the water during the middle hours of the day, stay away from early morning/late afternoon," said Carlstrom.
He says the reason it seems like there have been a lot more shark sightings and close encounters with great whites in this area is because their numbers have increased in recent years.
"Really, over the course of the last decade, we've seen increasing seal numbers and corresponding numbers of sharks," he said. "We really don’t fully understand it. That's why there's a lot of research going on."
But as to whether they would ever try to limit the seal population to reduce the number of sharks near the Cape, Carlstrom says that's out of the question.
"That's messing with nature. That's part of the reason the seashore exists to ensure the wildlife," he said.
Experts say it appears the sharks are here to stay in the waters off Cape Cod, and that's why they're working so hard to educate people on how to co-exist with them.