Five crew members missing after a crab fishing vessel sank in the frigid waters off Alaska were feared dead after authorities called off a search for those working in the one of the most dangerous industries in the U.S.

Two other crew members were rescued after the disaster Tuesday, telling authorities they were the only ones who made it into a life raft, the Anchorage Daily News reported. They were hypothermic and have since been released from a hospital.

The Coast Guard said it used helicopters, planes and a boat to look for the missing crew members for 20 hours before calling off the search late Wednesday because they were not likely to have survived.

The agency didn’t release any details Thursday on what caused the boat to sink, saying talking to the survivors is part of the investigation.

The boat, named the Scandies Rose, was carrying a load of crabbing pots for the start of the winter season, Dan Mattsen, a partner in the boat that is managed by Seattle-Based Mattsen Management, told the Seattle Times.

Crabbing boats endure perilous conditions in Alaska waters that have been immortalized in the Discovery Channel reality show “Deadliest Catch.” Workers face dangers like huge waves, freezing conditions and massive crab pots that could crush them.

Gary Knagin of Kodiak, Alaska, the brother-in-law of the boat’s skipper, Gary Cobban, told The Associated Press on Thursday that he doesn’t think the five crew members will be found alive.

“We know the risks involved in this profession, and I’m not holding out hope,” said Knagin, who worked on a crab boat for 30 years in the Bering Sea. “I’ve seen this too many times. There’s a 13-hour window in those conditions, and they passed that.”

Ashley Boggs of Peru, Indiana, said she was due to marry crew member Brock Rainey after he returned from Alaska and hasn’t given up hope.

“I’m just praying and hoping they find him on land or something,” she told AP on Thursday. “I really felt like he was alive.”

Boggs said she received a call from Rainey on New Year’s Eve saying the conditions were bad.

The 130-foot (40-meter) boat, which had left from Dutch Harbor, sent a mayday distress call, and the Coast Guard launched a rescue.

The vessel’s last known position was 170 miles (270 kilometers) southwest of Kodiak Island, near the southern tip of Alaska, and it sank about 10 p.m. Tuesday, the agency said.

Rescue crews arrived about 2 a.m. Wednesday and battled winds of more than 40 mph (64 kph), 15- to 20-foot (4.5- to 6-meter) seas and visibility that was limited to 1 mile (1.5 kilometers), Coast Guard Petty Officer 2nd Class Melissa McKenzie said.

“That’s rough conditions,” she said Thursday.

McKenzie said the air temperature was about 10 degrees (12 below zero Celsius). The estimated water temperature in the area was 43 degrees (6 degrees Celsius), National Weather Service meteorologist Shaun Baines said.

Rescuers saw a faint light in one life raft, but a medic lowered from a helicopter found it empty, the Anchorage Daily News reported. Another faint light was spotted about a half-mile (1 kilometer) away, where searchers found the two survivors, ages 38 and 34.

The men told rescuers that they were able to get into survival suits and didn’t know if the other five crew members did, the newspaper reported. The suits offer flotation and hypothermia protection.

The National Institute for Occupational Safety and Health refers to commercial fishing as one of the most dangerous occupations in the U.S. It said there were 179 deaths in Alaska fisheries between 2000 and 2014.

From 2010 to 2014, there were 66 vessel disasters in Alaska waters, including sinkings, fires or other events that forced crews to abandon ship, the agency said. While most crew members survived, 15 people died. Leading causes of fatal disasters were instability and being hit by large waves, the agency said.

Gary Knagin’s wife, Gerry Cobban Knagin, wrote on Facebook that her brother Gary Cobban and his son, David, were on board.

Knagin of Kodiak, Alaska, told Anchorage news station KTVA-TV that her brother, the skipper on the boat, and his son were not among those who had been rescued. She said she hoped he was “on one of the little Islands waiting for us!”

“We, the Cobban Family, extend our thanks and gratitude to all the Coast Guard men and women involved with the search and rescue of crew members on the F/V Scandies Rose,” she said on her Facebook page. “The horrendous weather made for an extremely tough search.”

(AP)