A Russian trawler has sunk off the Kamchatka peninsula, with 54 sailors so far confirmed dead.
Sixty-three people have been rescued, many suffering from hypothermia, according to a maritime rescue centre in Russia’s Far East.
The Dalniy Vostok freezer trawler had 132 people on board when it sank.
Seventy-eight of the crew were Russian, with the remainder coming from countries including Latvia, Ukraine, Myanmar and Vanuatu.
The Dalniy Vostok went down in the Sea of Okhotsk, 330 km (205 miles) west of Krutogorovsky settlement, at around 06:30 (20:30 GMT Wednesday).
“The rescue operation is going on, we are still looking for 15 people,” Viktor Klepikov, coordinating captain of the Petropavlovsk-Kamchatsky maritime rescue coordination centre, told Reuters news agency.
“At this time we do not know what might have caused the tragedy.”
One theory is that drifting ice may have holed the vessel, according to Russian emergency services.
Water flooded the engine compartment and the trawler then sank within 15 minutes, a local branch of the Russian Emergencies Ministry said.
But Russian news agency Tass quoted a senior official in Kamchatka as saying the boat foundered while trawling a 100-tonne dragnet.
Sergei Khabarov said that safety rules might have been flouted with cargo limits being exceeded.
The ship did not send out a distress call before sinking, according to local media.
Some two dozen ships and a rescue helicopter are involved in searching for remaining survivors in freezing waters around zero degrees C (32F).
The 15 people who are still missing are thought to have been in the ship’s hold as the trawler sank, reported Tass.