A California boat captain who abandoned ship when the dive boat Conception caught fire in 2019, killing 34 people on board, will spend four years in federal prison after being convicted in the criminal case last year.

U.S. District Judge George H. Wu handed down the sentence for Jerry Boylan, 70, on Thursday after a Los Angeles jury found him guilty of one count of misconduct or neglect of ship officer, an offense commonly called “seaman’s manslaughter," according to a release from the U.S. Attorney's Office, Central District of California.

The fire broke out on Labor Day off the coast of Ventura County when the Santa Barbara-based boat was anchored off Santa Cruz Island. One crew member and all 33 passengers on lower decks were killed.

Boylan was the first person to jump ship and didn't do enough to try to fight the fire, a jury found.

"The stakes were life and death," the U.S. Attorney's Office wrote in its sentencing position, which was obtained by the Ventura County Star, part of the USA TODAY Network. "And yet defendant did nothing to keep his passengers and crew safe − in the days, weeks, months, and years leading up to the Labor Day Weekend trip, and on the night of the fire itself."

Boat captain indicted:California boat captain indicted on manslaughter charges for 2019 fire that killed 34 people aboard Conception

Conception boat fire victims were ages 16 to 62

During Boylan's two-week trial last year, his defense attorneys argued their client did everything he could to save everyone on the boat.

But prosecutors told jurors Boylan could have prevented the deaths had he followed Coast Guard rules requiring him to keep a night patrol to prevent such disasters and to train his crew on how to respond to a fire.

The victims, ages 16 to 62, included a hairdresser, a Hollywood visual effects designer, an Apple executive and two teenage girls.

During the trial, defense attorneys acknowledged Boylan jumped off the ship after making a mayday call but said flames were 15 feet high and the wheelhouse had filled with smoke. Boylan, his second captain and a deckhand had reboarded the boat in the back, but they could not reach the firefighting equipment because of the flames, his attorneys said.

"Soon after he woke up during the fire, defendant jumped overboard into the ocean. He was the first person to jump off that boat," lead prosecutor Matthew O'Brien said. "Defendant also instructed his crew members to jump overboard rather than fight the fire. ... The 34 people who were killed didn't have a chance to jump overboard."

The equipment included two "fire stations" that had 50-foot hoses that can pump an unlimited amount of seawater on a blaze, they said.

Video taken below deck shows victim's last moments alive

O'Brien said that just before jumping ship, Boylan used precious seconds to call the Coast Guard rather than trying to fight flames when he knew help was more than an hour away.

The FBI recovered a 24-second video from a phone found in a passenger's coat pocket at the bottom of the ocean. The video shows the increasingly distressed passengers trapped below deck with fire blocking a staircase and an escape hatch.

"Passengers didn't know it, but their captain had already jumped overboard," he said. "The video was the last time any of them would be seen alive."

The video was taken at 3:17 a.m., and Boylan's distress call to the Coast Guard came at 3:14 a.m., O'Brien said. The Coast Guard arrived at about 4:30 a.m.

"The 34 people below deck were reacting to the smoke filling the dark, cramped bunkroom," O'Brien told jurors as family members cried and tried to comfort one another. "Some of them were putting on shoes to try to escape. One of them used a fire extinguisher to try to fight the fire. And some of them huddled together low to the floor where there was less smoke."

'A needless tragedy'

U.S. Attorney Martin Estrada called the disaster a "needless tragedy" and said the victims' loved ones would be forever devastated, according to a statement released Thursday.

“While today’s sentence cannot fully heal their wounds, we hope that our efforts to hold this defendant criminally accountable brings some measure of healing to the families," Estrada said.

Contributing: Cheri Carlson

Natalie Neysa Alund is a senior reporter for USA TODAY. Reach her at [email protected] and follow her on X @nataliealund.