Creating an amazing nature spectacle at several beaches in South Florida, thousands of blacktip sharks descended causing swimmers to take cover as the creatures swam on their annual migration.
Officials in Broward and Palm Beach counties on Florida's south-east coast have temporarily closed several beaches to swimmers and surfers as a precautionary measure, although marine biologists say that there is little risk to humans.
Researchers at Florida Atlantic University say they have counted more than 15,000 sharks, most less than 200 yards from shore. The sharks are heading north to North Carolina after migrating south for the winter. The migration happens every year, but usually begins and ends before peak beach season, unlike this year.
"We don't have a sandbar." lifeguard Craig Pollock, a Palm Beach lifeguard supervisor told ABC News. "A lot of times when we have a sandbar the sharks stay off of the shore a little further."
Many beaches are flying a double red flag Thursday, warning beachgoers to stay out of the water.
Experts warn that if you're swimming at any South Florida beach that doesn't have the double red flag or hasn't been closed, be sure to swim along beaches where lifeguards are present. Also, leave your jewelry on the shore. Scientists say sharks are attracted to silver, along with the colors yellow and gold.
According to the International Shark Attack File at the Florida Museum of Natural History, there were 80 unprovoked shark attacks worldwide in 2012, 26 of which were in Florida.