Sharks migrating off coast of Florida by the thousands

WEST PALM BEACH, Fla. - An aerial view of the Atlantic ocean shows thousands of sharks swimming in large groups along the coast of Florida as they have arrived for the winter.

The video shared by Florida Atlantic University researchers on their Shark Migration Facebook page shows thousands of sharks spotted from Palm Beach to Jupiter. "That fishing boat's having a blast," Dr. Stephen Kajiura, a scientist at FAU is heard saying on the video. Dr. Kajiura studies the migration of sharks and has been surveying them from the skies since 2011. 

Very few sharks, researchers pointed out, were spotted from Miami to Palm Beach. 

Dr. Kajiura said his team recently expanded the project to include tagging them with trackers to study the pattern of their migration. Researchers spent the weekend tagging some of them with transmitters.

The sharks he's studying are black tip sharks, and they have recently arrived along the Florida coast. Dr. Kajiura said they typically stay from January until March, when they make their way back up the coast toward Georgia and the Carolinas. 

One of the photos researchers shared on Instagram shows a paddle boarder not too far away from the massive group of sharks.

"Lucky paddle boarder (lower left) about to encounter hundreds of sharks," it said. 

Photos on the Facebook page show them checking the tag placement, measuring the sharks, and carefully removing the hooks from their mouths to let them go safely.

Dr. Kajiura said the sharks will move north, where the females will give birth around June, mate again, then move back to Florida in the winter. Each year, he flies over the sharks in a Cessna with the camera attached to it to see where they are and when they've returned. "Being the pilot and the scientist, I know exactly what I need to do," he said.

But he said even though there are large numbers of black tip sharks, they are skittish and will usually swim away when they're approached. "It's visually compelling to see these sharks close to shore, but it's not cause for concern," he said. "It's indicative of a healthy ecosystem," he said.