Thousands of blacktip and spinner sharks have been seen along the coast this week, heading north after migrating south for the winter, marine biologists said, closing beaches temporarily.
Lifeguards at Midtown Beach in the Palm Beach area observed spinner sharks in the ocean and raised red flags Thursday, indicating swimmers should not enter the water, NBC News reported.
"It's dangerous. It's not what you would expect. Families come out here to enjoy the weather, beach and sand, but now they can't," beach goer Guirlene Exantus said.
"We don't have sharks in Washington. I just wanted to go swimming," said Tori Bradshaw, who had just arrived in Florida from her home state.
"If there are sharks, you aren't going to find me in there," said Burt Abrams, visiting from Cleveland.
Although several beaches were closed during the week, there were no reports of shark bites, the South Florida Sun Sentinel reported Friday.
The sharks pass through the area and typically prefer shallow water, The Palm Beach Post said, although it noted only 663 confirmed and unprovoked shark attacks in Florida from 1882 to 2012, an average of five per year.
"Many sharks are found virtually in ankle-deep water," said George Burress of the Florida Museum of Natural History in Gainesville.
The uproar this week convinced Gail Holland of Boston, enjoying Ocean Reef Park in Riviera Beach, to avoid taking chances.
"I am definitely not going to go in the water," she said, "but that doesn't deprive me of the vacation at all. I enjoy the walk on the beach, the sunshine and the beautiful scenery."