More than a dozen sharks were spotted Tuesday by a drone patrol off the waters of Robert Moses State Park.

A drone flying 200 yards offshore at Robert Moses State Park spotted over 50 sharks in the water. Swimmers were called out of the water a second time when a pair of dolphins were mistaken for sharks.

It comes one day after police say a 15-year-old male surfer was bitten by a shark at Kismet Beach on Fire Island. They say that victim swam to shore, and a Good Samaritan provided medical assistance until officers responded and continued the care.

In another incident, a 15-year-old female was treated for three small puncture wounds on her left leg by state park EMTs at Robert Moses State Park, state park officials say.

New York state Parks Regional Director George Goreman says the sharks spotted were sand sharks. He says the experts say these bites are a mistake because the sharks think they are feeding on bay fish or bunker fish.

Warning signs are expected to go up at area beaches.

Goreman says a total of eight shark bites were reported last year.