South Florida beaches in Palm Beach County were closed to swimmers this week as thousands of blacktip and spinner sharks migrated along the East Coast, heading north with the arrival of Spring. Local station WPTV reported an estimated 15,000 sharks were visible in just one day, or an average of 1,000 sharks per square kilometer.
The mass of sharks were easy to spot in the calm, clear waters of the Atlantic Ocean. Beach-goers watched the exciting show as sharks swam nearshore, sometimes attacking baitfish in the surf. Spinner sharks, and even blacktips, are known for their aerial jumps and twirls. The two species look very similar to the untrained eye.
Florida Atlantic University (FAU) shark researcher Steve Kajiura told local newspaper TC Palm that during January and February, a shark is only an average of 60 feet away from swimmers.
Sharks are very common in Florida waters, and pose little threat to people, even if certain media portrays differently. Much of the species' natural prey are silver-sided baitfish, as most fishermen can attest. But sometimes a fluttering hand or foot from a swimmer can be mistaken for baitfish.
“There are thousands of sharks right there, and yet this year, there have been no bites in Palm Beach County waters,” he said. “Our data has shown that the bulk of the migration occurs in January and February, but it may be a little behind this year due to the warmer weather and water temperatures.”
In the coming weeks there will likely be more closed beaches along Florida's East Coast. The migration continues as far north as North Carolina before dispersing. Below, see video of the sharks from a frigatebird view: