In recent years, it's not officially summer until the great whites arrive.
"It is something that everyone talks about every summer,” said Nick Cecchi of Yarmouth.
And this summer she's here, right on schedule.
"This is not unusual,” said Dr. Greg Skomal. “We fully anticipate that the sharks would be here by now. We're not seeing large numbers yet. I think the water temperatures are still quite cold."
The Atlantic White Shark Conservancy spotted a 15 footer - a female - off South Beach in Orleans Monday in 15-20 foot deep seas.
"We're able to get gopro video of the shark which is what the scientists use to ID the shark and catalog the shark,” said Cynthia Wigren, Atlantic White Shark Conservancy. “It's only been in the last five years that scientists have had predictable access to white sharks in the western North Atlantic."
Experts believe she's well into her 20s, but aren't quite sure she's a return visitor, yet. They'll analyze her markings this week. Last summer, 68 great whites were tagged off Cape Cod, as more migrate up north to feed on the growing population of seals.
"Sharks are here to consume seals,” Skomal said. “Don't swim in close proximity to seals. Don't swim alone. Don't swim great distances from shore."
That's not a problem for most vacationers like the Keeley family.
"You just have to be aware of where you are,” said Lynn Keeley, a vacationer. “I'm more comfortable in my beach chair, that's for sure."
© 2015 CBS Interactive Inc. All Rights Reserved.