Trying to rinse sand off his body, Eugene Theodore Jr. took a dip up to his chest in the ocean off Jones Beach Wednesday evening before he was swept away, authorities said as the Coast Guard Thursday called off the search for the beachgoer.

Theodore, 22, of Queens Village, was one of two beachgoers at separate South Shore beaches who were reported missing Wednesday when temperatures on Long Island broke records, and both are now presumed to have drowned, authorities said.

The other missing beachgoer, identified by authorities as Emanuel Tiburcio, 19, of Brooklyn, was with friends at Long Beach and was last seen floating face down in the water beyond a jetty.

There were no lifeguards on duty at either beach because the season hadn't officially started.

Rescuers called off the search for Theodore at about 12:30 p.m. Thursday after concluding he could not have survived more than 16 hours in the 58-degree water.

Theodore had gone into the water with two friends Wednesday shortly before 8 p.m. near the Central Mall and Field 4, officials said. The other two swimmers, both 18, got out, but Theodore, who friends said was an experienced swimmer, didn't make it back to shore, said Petty Officer Robert Sebastiao of the Coast Guard.

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A Nassau County police helicopter, a Coast Guard helicopter from Air Station Cape Cod and a Coast Guard rescue craft searched 27 square miles Thursday and Wednesday. Coast Guard boats in the area for the weekend air show also helped out, Sebastiao said.

Long Beach City Manager Charles Theofan said he's concerned that one or both of the bodies could wash up on the beach during Memorial Day weekend.

At Jones Beach Thursday, Morgan Haber, 19, of Westchester, sat on the sand as her friends tossed a ball Thursday.

Told of the drowning, she said she doesn't like to swim in the ocean: "This is why I don't go in the water. . . . I'm petrified of drowning."

With John Valenti