Ocean Rescue Effort Ends in Death of 17-Year-Old : Tragedy: The youth apparently drowned in trying to aid an 11-year-old cousin, whom lifeguards brought in unharmed. Earlier a child was saved from a back-yard pool.

A 17-year-old Santa Ana boy died in an apparent drowning Sunday after he tried to save his 11-year-old cousin, who was caught in strong currents near the Newport Pier, police said.

The drowning occurred a few hours after an off-duty police officer successfully revived a neighbor’s child who had plunged into a back-yard pool in Irvine.

In the Newport Beach incident, Julio Serna was found tethered at the wrist to a body board in the ocean off 23rd Street, where a lifeguard pulled him out, said Richard McAnally, senior deputy coroner. The younger cousin, who was not identified, was not harmed.

Craig Farmer, a marine safety officer for the city, said Serna had drifted off from a group of body boarders and was found beneath his board when a lifeguard went out to rescue him and another boy.

Serna was taken to Hoag Hospital in Newport Beach at 3:45 p.m. and pronounced dead at 4:05 p.m. His death is tentatively classified as drowning pending an autopsy scheduled for today, McAnally said.

Eric Bauer, another marine safety officer for Newport Beach, said that if Serna’s death is determined to be a drowning, it will be a “very unusual” one.

“You figure you have basically a flotation device attached to you,” he said.

Farmer added that if it is a drowning, it is the first this summer along the city’s shoreline.

“How he gave up the board and ended up drowning is speculation at this point,” he said.

Police said Serna noticed his cousin struggling in the surf and went out to help him. A few minutes later a lifeguard saw both of the youths having difficulty about 100 yards offshore in particularly rough, choppy surf.

A lifeguard swam out to them and found the 11-year-old still floating on his board. The lifeguard then felt Serna’s body brush against his leg and pulled him up to the surface by the 4-foot-long tether.

The lifeguard immediately began cardiopulmonary resuscitation on the unconscious youth, who was not breathing. A rescue boat took them to paramedics.

Farmer said that because of the rough ocean conditions, lifeguards have been unusually busy. On Sunday, lifeguards performed about 150 to 200 rescues, he said.

In Irvine, a 4-year-old boy who was found unconscious at the bottom of a pool was revived by an off-duty police officer, fire officials said.

The boy’s parents had apparently left the child unattended in their back yard for a few minutes about noon Sunday and returned to find him at bottom of the pool, fire officials said.

Richard Worcester, an Irvine police officer who lives next door in the 15400 block of Alsace Circle, heard the parents’ screams for help, ran around a fence into their back yard and administered cardiopulmonary resuscitation to the child.

Worcester was able to revive the child before paramedics arrived, fire officials said. The child, identified as Michael Tang, was in good condition, but was taken to Orange County Children’s Hospital for observation.

“I guess I was at the right place at the right time,” Worcester said.

“When I grabbed him, he was as limp as a wet noodle. I was a little scared because I’d had never given CPR to anyone who has survived,” said Worcester, who added that he has performed the rescue technique on four other people.

“This time it worked,” he said. “It was really rewarding being able to use my training . . . but today I wasn’t a police officer, I was just a neighbor.”

Times staff writer Danny Sullivan contributed to this report.