Rough surf churned up dangerous conditions from swimmers and complicated rescue efforts along Florida beaches over a holiday weekend in which at least four people went missing in boating and swimming incidents, authorities said.

A swimmer was missing Monday off Ormond Beach in Florida, emergency responders said. Also Monday, the Coast Guard searched for a 26-year-old woman missing from a boat returning to suburban Miami from Stiltsville, a cluster of homes built on pilings in South Florida's Biscayne Bay.

Elsewhere, a search was called off for an 11-year-old boy who disappeared Saturday off Jacksonville. On Sunday, authorities used a personal watercraft to bring a woman to shore in the same area of Little Talbot Island, but a man remained missing in the water.

Beachgoers also pulled two men from the water Sunday on Daytona Beach Shores. Officials said one died, and the other remained hospitalized.

On the Gulf Coast, a 15-year-old Mississippi teenager was missing Monday after he disappeared during a weekend trip to a barrier island, said Coast Guard spokesman Carlos Vega.

Vega said Omar Gonzalez of Petal, Mississippi, and a 17-year-old friend were swept off the west end of Ship Island in the Mississippi Sound after arriving on a passenger ferry Sunday. He said the 17-year-old was found clinging to a buoy in a Gulfport, Mississippi, ship channel late Sunday and was taken to a hospital with minor injuries.