Canadian coastguards are trying to rescue the occupants of about 100 boats carrying seal hunters trapped by pack ice off the country's eastern coast.
Several boats are hemmed in by the ice
Several of the boats are threatened with damage or sinking, and at least one crew had to abandon ship.
Fishermen have described conditions as the worst for more than 20 years.
The hunt, described by activists as cruel and unnecessary, is currently in its third and largest stage off the coast of Newfoundland province.
A spokesman of the Canadian Fisheries and Oceans Department said two-thirds of the quota for the cull had already been filled.
The total quota for the hunt is 270,000 seals.
Food and fuel shortage
Winds pressing the ice floes in towards land have made conditions difficult for the boats, some of which are hemmed in and face having their hulls cracked open.
Conditions are set to continue until the end of the week and could deteriorate further, coastguards say.
Canada's CBC network said some of the boats were running out of food and fuel.
A crew member of one of the stranded boats, the Southern Pride, told the network the ice had crushed a speedboat and left their vessel high and dry.
"I've never, ever experienced nothing like this. We've been in the wrong place each time," said Gill Cadwell.
Canada insists that the cull, which is smaller than last year's, is necessary to keep seal numbers down.
Seal pelts are sold to the fashion industry in Russia, China and Norway, and seal blubber is used for oil.
The culls regularly provoke an international outcry, with celebrities such as Sir Paul McCartney and Brigitte Bardot being involved in the campaign against them.