A group of Florida fishermen -- including two sheriff's detectives and a paramedic -- rescued a Texas couple who had fallen off their boat off Key Largo and treaded water for 13 hours.

Sean McGovern, 49, and Mellissa Morris, 51, were rescued Saturday seven miles off Hallandale Beach, the South Florida Sun Sentinel reported. The boat was drifted off, CNN reported. The Coast Guard said the boat eventually washed up on a Fort Lauderdale beach.

"The (woman) couldn't even walk," fishermen Steve Couch told the newspaper. "Her legs were like sticks. They couldn't even bend."

The couple said they fell from their 30-foot Island Hopper about 6 p.m. Friday. Neither was wearing a life jacket when they were found, the Coast Guard said.

Couch was fishing with his son-in-law, Broward County sheriff's detective Adam White, detective Josh Webb and firefighter/paramedic Keith Silvas. They had been out for about 20 minutes when they spotted the pair because of birds circling the area.

"They are very lucky -- they didn't have any signal device," U.S. Coast Guard spokesman Mark Barney told CNN. "They were trying to signal people down with their T-shirt. To be located and recovered by off-duty cops and a firefighter -- that's a stroke of luck right there."

The couple suffered mild hypothermia and jellyfish stings, the Broward County sheriff's department said.