ANCHORAGE, Alaska -- The Coast Guard Monday identified the missing crew member from a fishing vessel that sank off Alaska's Aleutian Islands, killing the captain and three crew members.

Chief Petty Officer Barry Lane said the Coast Guard cutter Munro searched for Satashi Konno of Japan overnight and aerial searches began at daylight Monday.

Lane said Konno, whose age was unknown, was wearing a survival suit. But even with the suit, water temperatures are at 36 degrees and Lane says that makes survival tough.

Lane said the Coast Guard still does not know if Konno is the crew member who fell from the rescue basket as it was being lifted into a helicopter.

The Seattle-based Alaska Ranger started taking on water shortly before 3 a.m. Sunday after losing control of its rudder 120 miles west of Dutch Harbor, which is on Unalaska Island. The 42 other crew members were rescued.

The 184-foot ship's owner, the Fishing Company of Alaska, said in a statement that it did "not have sufficient information to determine why the vessel foundered."

Seas with up to 8-foot waves and 25-knot winds were reported at the time the ship sank, said Chief Petty Officer Barry Lane. He said the Coast Guard was investigating the cause of the sinking.

Some of those on board the Alaska Ranger were taken to Dutch Harbor in the sunken vessel's sister ship, the Alaska Warrior. The ship arrived about midnight at a private dock, where access to survivors was not allowed. The vessel took part in the rescue operation along with two Coast Guard helicopters that were used to pluck crew members from the water and from life rafts, Lane said.

At least 13 of the crew members were not in life rafts, and were picked out of the ocean along a mile stretch. They were wearing survival suits and had strobe lights on.

Other survivors were on board the Coast Guard cutter Munro, which remained at the scene to search for the missing crew member. A C-130 also remained to help search for the missing crew member, whose name was not released.

Coast Guard officials said it was unknown how or when the four died.

The company identified them as ship's captain, Eric Peter Jacobsen, 65, of Lynnwood, Wash.; Chief Engineer Daniel Cook, hometown unknown; Mate David Silveira of San Diego, and crewman Byron Carrillo, believed to be from Seattle. The company did not give the ages of Cook, Silveira or Carrillo.

"They were incredibly brave, hard working men. Our hearts are broken," the company said in a statement. The men's ages and hometowns were not released.

His family said Captain Jacobsen, a veteran of the fishing industry, was a hero both at home and at sea.

"He was a great dad. We didn't have very much time with him here at home, but when he was here, he made it the best times that we could possibly have," said Scott Jacobsen, his son.

Captain Jacobsen's family said they have serious questions about what would cause a fishing boat almost 200 feet long to suddenly take on water and sink in relatively calm waters.

"(It) raises the question, something was wrong, went really wrong. So we're interested in the details. Things like that don't just happen. My dad's been fishing all his life and he's never had anything remotely close to this happen," Scott Jacobsen said.

In Seattle, people brought flowers to the Fishermen's Memorial or paused a moment near the monument following the accident.

"I'm ex-Navy. I know what it's like to be in a crisis and I just wanted to pay my respects," said Dan Jacobs.

State environmental regulators were notified that the ship was carrying 145,000 gallons of diesel when it sank in deep seas, according to Leslie Pearson, emergency response manager for the Alaska Department of Environmental Conservation.

According to initial reports, an oil sheen covered an area of a quarter mile by a half mile, Coast Guard spokesman Ray Dwyer said. The strong winds made any cleanup effort unlikely, but those conditions would disperse a spill much more quickly than calm weather, Pearson said.

In December, an engine fire damaged another of the company's ships, the Alaska Patriot, while it was docked near Dutch Harbor. No one was injured in the blaze.

In 2006, the Fishing Company of Alaska, the owner of a catcher-processor ship it managed and the ship's captains were fined a combined $254,500. The National Oceanic and Atmospheric Administration's Fisheries Service said the company -- as well as the ship's owner, Alaska Juris Inc., and its captains -- committed numerous violations, such as tampering with or destroying equipment used by industry observers and failing to provide observers a safe work area.

Federal officials said the case stemmed from a multiyear investigation that documented a range of federal violations, including keeping inaccurate information on required reports and fishing contrary to seasonal closures.