Harp seals (Pagophilus groenlandicus) rely on sea ice in the gulf and off Newfoundland and Labrador to give birth to, nurse, and wean their pups.
"This particular species really prefers ice" over land, Hammill said.
After being born, the white-furred pups nurse for 12 to 14 days. Then the mother leaves and the pups are weaned.
These juveniles moult during the next two weeks, trading their snow-white coats for silver ones flecked with small dark spots along each side.
Poor ice conditions mean more pups may die, while less food could be available for those being weaned.
The pups can't swim very well and they tire quickly, Hammill pointed out.
"They are little butterballs of fat that pop around like wine corks," he said. "They will drown. They need the ice to rest."
Ted Miller of Memorial University in Saint Johns, Newfoundland, added that "the seals are absolutely ice dependent, and their numbers will get hammered if it goes down."
Officials say they expect high mortality among pups this year. Some groups are even estimating that close to 100 percent of the pups will succumb due to fragile ice.
In response to the dire conditions, Canadian fisheries minister Loyola Hearn announced this past Thursday that the ministry had reduced the number of seals that hunters can catch this year by 20 percent, to a total of 270,000 instead of last year's quota of 335,000.
About 30 percent of the seals are hunted in the Gulf of St. Lawrence. Most of the hunt—70 percent—occurs off Newfoundland and Labrador.
Officials say the harp seal population off the east coast of Canada is around five million animals—almost triple what it was in the 1970s—and that the hunt is necessary to keep the population under control.
But animal welfare group IFAW argues that the hunting limit is unsustainable and that the population will continue to decline if more than 165,000 seals are caught.
Sheryl Fink, a senior researcher with IFAW, said in a statement that she had flown over the region but had seen few seals.
"Normally," she pointed out, "we should be seeing thousands and thousands of seals."
Other animal welfare groups, including People for the Ethical Treatment of Animals, say the hunt is cruel and unnecessary and want it to be called off.
Hammill, of DFO, said the most recent harp seal survey, carried out in 2004, found that the pup population had been stable since 1994.
The next survey will be moved up to 2008, he added, instead of a year later as planned.
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