Every year, during shark season, Professor Stephen M. Kajiura of Florida Atlantic University receives reports that thousands of sharks are moving near the shores. December to April is a time when sharks migrate from cold water in search of food, said Kajiura.

Kajiura said he surveys the Florida beaches every year from December to April to see herd of sharks travelling near the beaches. Last week, professor Kajiura saw thousands of blacktip sharks when he was flying over a beach in his plane. He captured a video and posted it on the Internet. Since then, the footage has gone viral on the social media.

There were more than 10,000 blacktip sharks at the time, and most of them were between Palm Beach and Jupiter, according to Kajiura. “And those are just the sharks in the video survey. We know there's more because we could see them on other side of the plane, out of the video frame. That was a gross underestimate”, Kajiura continued.

The expert predicted that the scene will be common until mid- to late March, because it is the time when the fish start moving to north. Many people avoid going near shores as they think blacktip sharks may injure them, but Kajiura believes blacktips are skittish.

When they observe human movement near them, they move away in the water, as per the professor. The shark species is known for more bites on humans than any other shark, but they bite when water is cloudier because they think a human hand is actually a fish, he explained.

The professor also said that humans are the biggest threat to the fish as more than 100 million sharks are killed by humans every year for meat.

AL News reported that, the sharks were spotted just off the coast of Florida beaches between Jupiter and Palm Beach, FAU reported.

"The interesting thing is these sharks are right up against the shoreline. You could stand on the shore and toss a pebble and hit a shark, they're that close."

"The sharks are not out to get you, and if they wanted to bite you, there'd be ample opportunity," says Kajiura. "But in this clear water, they can easily see you're a human, not a fish. Besides, these sharks are skittish, and they'll likely swim away, even if you try to get close."