A family of 5 celebrating his birthday is among the dreaded victims of the fire of a California dive boat

The fire of the boat loaded with divers broke shortly after Monday morning, after the last part of a three-day trip off the island of Santa Cruz. The 34 people sleeping under Conception's deck are presumed dead and the authorities have canceled the search for survivors.

Among them, five family members from Stockton, California, who were aboard the dive boat celebrating an anniversary, said Dominic Selga to CNN's subsidiary KOVR.

Selga said that he was trying to understand that his mother, Fernisa Sison, her husband, Michael Quitasol, and her three half-sisters – Angela Quitasol, Evan Quitasol and Nicole Quitasol – are probably dead.

"You know deep inside you that it's true, that they're dead and that they were in this boat and that they will not be found," Selga told the affiliate .

The family loved diving and signed up for a long weekend of unlimited exploration of colorful underwater life and the gastronomy that goes with it. The adventure was to celebrate Michael Quitasol's birthday, he said.

"What were they thinking about, what happened, why did it happen, what did they wake up to, were they awake, were they even woken up?" he said.

Three of the family members worked for Kaiser Permanente Central Valley, which said it was providing support to those affected by the incident.

"We are very saddened by the tragic deaths of our colleagues, Fernisa Sison, Michael Quitasol and Evan Quitasol, as well as all those on board the Conception, and our condolences go out to their family and friends," said Corwin. Harper, Senior Vice President of Kaiser Permanente Central Valley.

Divers saw more bodies in the wreckage

It is unclear what triggered the fire in the 75-foot boat. There were 39 people on board – 33 passengers and six crew members, said Coast Guard Captain Monica Rochester. Five members of the crew escaped the flames and were saved.

A total of 20 bodies were found – 11 women and nine men, said Sheriff Bill Brown of Santa Barbara County.

The search and rescue operation for missing persons has been suspended and it is now a recovery mission, Rochester said.

"It's never an easy decision to suspend research efforts," Rochester said. "We know that it is a very difficult time for the families and friends of the victims."

The crews traveled a distance of 160 miles for nearly 24 hours. Divers saw bodies in the wreckage but were unable to retrieve them until nightfall as the boat was unstable, authorities said. Crews will try to stabilize the boat so divers can enter and recover the remaining bodies.

DNA samples are collected from family members and the authorities will use fast technology to identify burned bodies beyond recognition.

The boat was about 20 miles from the mainland coast near Santa Cruz Island in the Channel Islands National Park.