Large shark school dissipates off Florida coast

This shark, among hundreds spotted near Tampa, Florida on Tuesday, ventured elsewhere Wednesday.

TAMPA, Florida (CNN) -- Scientists did not spot any sharks Wednesday morning around the place where, one day earlier, hundreds of them were videotaped in shallow waters, leading authorities to warn swimmers to be careful.

Sharks frequent the warm waters of the Gulf of Mexico, and scientists said such large numbers are not unusual. Still, the large school had prompted authorities to alert swimmers and fishermen Tuesday to possible danger.

For two hours Wednesday morning, scientists surveyed the area around Anclote Key, north of Tampa. Working with fishermen who tried to attract sharks using chum, they were unable to spot any sharks, said Sue Ellen Richardson, a spokeswoman for the Florida Aquarium. No sharks were spotted by air.

VIDEO Public safety officials issue warnings against swimming and boating in area where sharks are seen congregating (August 14) Play video (QuickTime, Real or Windows Media)

The weather in the area had started to deteriorate, with waves churning up the water, making it murkier.

Kevin Doll, a spokesman for the Pasco County Sheriff's Office, said the public should remain alert to possible dangers in what he described as "an abundance of caution."

"This is a relatively common thing," said Bob Hueter, director of the Center for Shark Research. "But what's not common obviously is to catch it on video and see it so close to shore. And that's what we're kind of excited about as shark biologists."

Hueter said most of the sharks were black tips. "It's a man biter, but it's not a man eater, and it's not especially dangerous along our coasts," he said.

Some other sharks were also spotted, according to Doll, including bull sharks and hammerheads.

Hueter said the sharks typically frequent the area all summer.

"They use it to give birth to their young, they feed," he said. "They're going to be here for probably about another month, and then, as the temperature in the water starts to go down, they're going to start migrating south and probably set up shop in the Florida Keys this winter."

Sharks have been in the news this summer. In July, a Mississippi boy's arm was bitten off by a shark at Pensacola Beach in northwest Florida. Doctors were able to reattach the arm, and the boy is recovering at home, although he remains in a light coma.