SAN DIEGO -- The Coast Guard has called off a search at sea for an Oceanside couple who went missing this week.

Authorities decided to end the search for Josh Hartman, 27, and his fiancee, 31-year-old Ana Martin Saturday evening "based on survivability in 63-degree waters," U.S. Coast Guard Lt. Jeremy Denning said.

The pair left Oceanside Harbor Thursday morning in their 32-foot fishing boat and were scheduled to return that afternoon. But family members said they never heard from them.

The next day, the boat washed ashore near Rosarito, a Mexican resort town about 20 miles south of the border, and no one was on board, Denning said.

The Mexican Navy, which searched the area off Baja California after the boat was found, said there was no obvious damage to the vessel, Denning said.

Hartman's mother said her son was an expert boater who had been working in commercial fishing for more than two years.

"We're praying all the time they're going to come home, and we'll continue to until we find out something else," Marsha Hartman said.