McCartney appeals for a stop to what he calls a "senseless slaughter" in a statement released Tuesday by Humane Society International. The group plans to document the hunt on film as it has for years.
"Their videos of the bloody seal slaughter provide the only vital evidence to demonstrate year after year that these seals are dying a horrible death for their fur," McCartney said.
Anti-sealing campaigns have helped inspire bans on seal product imports in the European Union, the United States, Mexico and other countries.
The hunt opened Sunday on the Front off northeastern Newfoundland and southern Labrador, as well as in the Gulf of St. Lawrence.
It has dwindled in recent years with fewer than 55,000 harp seals landed last year compared to a federal quota of about 400,000. Hunters were urged to ensure they have a buyer before heading out.
Eldred Woodford, president of the Canadian Sealers Association, said he won't be going to the ice for the first time in 20 years. That's because just one buyer so far has indicated demand for 30,000 harp seal pelts, he said from Twillingate, about six hours north of St. John's.
"It's a very limited hunt this year."
The federal government set the allowable catch at 400,000 harp seals, 60,000 grey seals and 8,000 hooded seals.
Woodford stressed that at about $35 each for the highest quality pelts last year, sealing provided a crucial boost.
"It's very important to smaller rural communities, coastal communities, which need every little bit of income they can get."
The hunt is also increasingly needed as a check on growing seal populations that feast on fragile fish stocks, Woodford said.
Jeffrey Hutchings, a biologist at Dalhousie University in Halifax, said in a recent interview that harp seal numbers have soared in the last 20 years.
"There is an imbalance, if you will, between predator and prey and it would not be surprising if the seals were having some impact on the recovery of cod. But the data really are not very clear in that regard."
The federal government has defended the commercial seal hunt as humane and sustainable.
"We continue to tell the truth about sealing, and the effects of seal populations on our marine ecosystems, to combat misleading attacks on the hunt from radical animal rights activists," Fisheries Minister Gail Shea said Tuesday in a statement. She was not available for an interview.
"We've challenged the EU's unfair ban on Canadian seal products, and are working with industry and our international partners to develop new products and open new markets."
McCartney made international headlines in 2006 when he staged a photo-op on the ice floes in the Gulf of St. Lawrence, beseeching Canada to halt the centuries-old hunt.
Terry Audla, president of Inuit Tapiriit Kanatami representing about 55,000 Canadian Inuit, said in a statement that McCartney should stick to what he knows.
"He is perpetuating myths, disregarding science and traditions, and turning a blind eye to the needs of working people to earn a living and feed their families."
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