LOS ANGELES — Rescuers continued searching overnight off the coast of Santa Cruz Island for passengers who were trapped aboard the Conception when the dive boat caught fire and sank early Monday.

At least 15 people were confirmed dead, and others were still missing early Tuesday, authorities said. The Associated Press reported that at least 25 people had been confirmed dead, but that number could not immediately be verified by officials.

Additional bodies were recovered from the wreckage overnight, but updated numbers were not available early Tuesday, said Amber Anderson, a spokesperson for the Santa Barbara City Fire Department.

Five people survived — the crew members, who had been awake and jumped overboard. Officials expressed little hope of finding anyone else alive.

“Time is of the essence right now,” Anderson said. “They’re feverishly searching for everyone out there.”

Local, state and federal investigators are trying to determine exactly what went wrong on the Conception, a 75-foot vessel once described by California Diving News as “California’s crown jewel of live-aboard dive boats.”

Victims who had signed up for a three-day dive excursion were believed to be in their bunks below deck when the fire started. The boat was about 20 yards off the north shore of Santa Cruz Island, part of the Channel Islands off the Ventura County coast. Thirty-nine people were on board when the fire broke out.

“Most everybody was asleep,” said Santa Barbara County Sheriff Bill Brown, noting the combination of remote location, rapidly spreading fire and the victims’ vulnerable position on the boat. “You couldn’t ask for a worse situation.”

The distress call crackled on Coast Guard radios around 3:15 a.m. Monday as flames engulfed the vessel.

“Mayday, mayday, mayday! … Conception … north side of Santa Cruz,” a man yelled. “I can’t breathe!”

Around that time, surviving crew members woke Shirley Hansen as they pounded frantically on the side of her nearby fishing boat, the Grape Escape. They had paddled over in a dinghy, some of them injured.

Two crew members jumped back into the dinghy in hopes of rescuing others. “But they came back and there was no one that they found,” Hansen said.

Hansen said it had been a quiet night in the cove in Platts Harbor. She and her husband, Bob, had spent the day on the water, cooked a calico bass she had caught and gone to bed. The Madera couple were unaware of the Conception, anchored about 200 yards away. They thought they were alone in the cove.

She described the pounding that awoke them as “horrific.”

“Our boat is very well made,” she said. “Having that sound come through (showed) they were very in need of help.”

She said there was so much smoke pouring from the Conception that she needed an inhaler. She said two of the crew members who made it off the dive boat had injuries to their legs. Some wore only underwear. One of the crew members gave his name as Jerry and identified himself as the captain.

“As it was burning, there would be explosions going off every couple of minutes,” Bob Hansen said. “It was probably some of the dive tanks exploding. It made me feel so helpless.”

Fire crews rushed to extinguish the boat, which sank about 7:20 a.m. Monday and now lies inverted on the ocean floor, about 60 feet down.

One crewman said his girlfriend was trapped aboard. Another said the Conception had celebrated the birthdays of three passengers —including that of a 17-year-old girl aboard with her parents —just hours before.

It was still dark early Tuesday as several fishermen carted equipment to the dock at the Santa Barbara Harbor where the Conception had departed days earlier. The men glanced at a row of glowing candles, each lit for a victim of one of California’s deadliest sea tragedies.

Mourners hung several dozen white, yellow and red flowers on a metal fence on the approach to the Sea Landing Dock.

The words “Fair winds and following seas; we’ll remember you on every dive,” were written on a flag signifying that a diver was in the water.

A message written on a pair of blue fins read, “We love you Conception.”

Jenny Stafford of Santa Barbara stayed by the memorial all night and said several relatives of victims visited the site.

“A man fell to his knees and sobbed uncontrollably,” Stafford said about the arrival of a victim’s father and sister from Chicago.

Stafford said she does not know how the town will heal.

“You better enjoy this every minute,” she said, pointing to the sun rising over the Pacific Ocean. “We are lucky to be here. This is so shocking.”