Shark video: Chopper 5 captures sharks migrating along Palm Beach, swimmers banned from waters

PALM BEACH, Fla. -- Area beaches are closed to swimmers after thousands of sharks have been spotted swimming along South Florida shores.

Marine biologists have spotted tens of thousands of sharks from Boca Raton to Jupiter since the start of the month. They say the marine animals are moving north, after migrating south for the winter.

Chopper 5 spotted hundreds of sharks swimming along Palm Beach this morning. (Mobile users, watch here: http://bit.ly/ZfKNr9)

On Tuesday off Midtown Beach, lifeguards spotted a school of spinner sharks moving through the area. The red flags quickly went up, meaning swimmers could not go in the water at that time.

Spinner sharks can be seen jumping out of the water and spinning, as they chase their prey through the water.

Although they're an interesting sight to see, sharks are quite dangerous to swimmers.

Doctors at St. Mary's Medical Center say they treat at least five to six shark bite victims a year. They say the injuries are usually minor, but even small shark bites can put victims at risk of infections.

To protect yourself from getting bitten by a shark, 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.

RELATED: Click here to track Lydia, a 2,000 pound great white shark swimming near Jacksonville