Global warming is making it harder for newborn harp seals to survive in the Gulf of St. Lawrence and off Newfoundland in Canada, the International Fund for Animal Welfare reported on Friday.
Rising temperatures have dramatically reduced the ice covering the water in these two areas, both places where harp seals return annually to mate and give birth, the advocacy group said in a scientific report.
In nine of the last 11 years, ice coverage has been well below the average noted over the last 37 years, the report said.
Solid ice is necessary for the survival of harp seal pups, said Sheryl Fink, a wildlife biologist and co-author of the report.
"Harp seals need the ice to give birth to their pups -- they won't come onto land," Fink said in a telephone interview.
They need a solid stable ice platform for three or four weeks, in order to give birth and to allow the pups to nurse enough to build up strength.
"If the ice isn't there when the mother seals are ready to give birth, they are forced to abort the pups in the water," she said. "They drown instantly. If there is ice but not as solid as necessary, so that it doesn't hold out for the entire nursing period ... (the pups) will fall into the water and drown."
Storms in the area can push the chunks of ice around in the water, putting the pups at risk of being crushed, Fink said.
Wildlife officials estimate there are about 5.5 million harp seals. That population is declining largely due to overhunting, but the pressure of depleted sea ice is another factor, Fink said.
The rise in global temperatures has been linked to emissions of carbon dioxide and other greenhouse gases.
The animal welfare group urged the Canadian government to lower the number of harp seals allowed to be killed by hunters each year.
Since 1995, the wildlife group said, the total allowable catch has increased even as the ice cover has diminished. In 2006, the limit was set at 335,000, which was 85,000 higher than the "sustainable yield" estimated by Canadian government scientists, the group said in a statement.
"The hunt draws global criticism to a region proudly trying to build a reputation for high tech research and development and first-class environmental tourism. This nationally- and internationally-offensive anachronism is inconsistent with such initiatives," the group's deputy director, Monica Medina, said in the statement.