The brief letter from the Canadian singer is posted on the website of the animal rights group People for the Ethical Treatment of Animals (PETA).
McLachlan writes that "sealers — like tobacco farmers and asbestos miners — need leaders to devise a practical exit strategy for them."
She says Canada should not "waste millions more in hopeless World Trade Organization challenges or paying to stockpile pelts when buyers already have seal pelts going back several years."
Ottawa has set a harp seal quota of 400,000 this year despite criticism that the allocation is too high because markets have dried up.
The federal government has long argued that the hunt is humane, tightly regulated and economically important to coastal communities.
Last week, the government of Newfoundland and Labrador said it would provide a loan of up to $3.6 million in a bid to boost this year's commercial harp seal hunt.
Provincial Fisheries Minister Darin King said the money will give hundreds of seal hunters an income this year.
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