Lifeguards had to close several South Florida beaches this week to keep people out of the water. Thousands of sharks have been migrating north near the beaches, later than usual this year.
And even at the beaches that weren't closed, people are taking extra precautions.
It's a school of mostly black tip reef sharks and spinner sharks, making their way north as the ocean warms for the summer.
Stephen Kaes, with Palm Beach County Ocean Rescue, says the migration path has lifeguards raising the double red flag a lot more often.
"They shouldn't be worried if they're out there by the lifeguards," Kaes says. "They're out there protecting the beaches, and they'll let 'em know when the sharks are in the swimming area. It may be dangerous if you're swimming some place that doesn't have a lifeguard, with nobody to tell you when the sharks are coming."
"Just give them their space," marine biologist Shari Tellman says. "Especially if they're feeding, it's probably a good idea to just give them their space."
While the beach closures are an understandable precaution, she insists we're not talking about Jaws. Tellman says these smaller, 4-5 foot sharks are more interested in chasing bait fish along the Gulf Stream, than tangling with humans.
"You know, we're going into their territory," Tellman says. "Have a healthy respect for that, but they aren't out to get us. Sharks should be protected by us more so than they need to be protected by them."
Several of the beaches have reopened after the migration, though unseasonably chilly temperatures likely will keep most swimmers away anyway.
Intermittent closures are still possible. When sharks are spotted near shore, lifeguards close beaches for at least a half-hour.
The Associate Press contributed to this story.