For most of the last 70 years, inhabitants of the Pribilof Islands, in the chilly Bering Sea off Alaska, have spent five weeks each summer clubbing seals to death for Uncle Sam.

For almost as many years, animal-defense groups have railed in vain against the "harvest," papering Congress with leaflets decrying the annual slaughter while the population of the North Pacific fur seal steadily declined.

The battle is about to be joined again, and in this year of federal deficits and born-again devotion to the bottom line, the antihunt forces may have an irresistible argument on their side: The seal hunt is a money-losing proposition.

For the past several years, the Pribilof seal hunt, conducted under an international treaty designed to protect the dwindling seal population, cost the U.S. government more than the value of the 20,000 or so skins it produced each year. The furs piled up, unsold, in warehouses.

The fur market is so bad that last year the Pribilovians, who have conducted the harvest for years as federal employes, declined to take over the hunt as a private venture, even when the government offered to throw in more than 30,000 pelts left over from previous hunts. The government had to grant the islanders a contract and sweeten the pot with more than $500,000 in cash before they would accept.

As a result, the international treaty that has governed the harvest since 1911 is facing an uphill fight for renewal this year. A bipartisan group of 44 senators recently told the State Department that they will oppose the pact unless the commercial harvest is discontinued.

"We cannot justify the expenditure of taxpayer money for the killing of seals," the senators wrote Secretary of State George P. Shultz.

Supporters of the seal hunt, chief among them Alaska's two Republican senators, are scrambling to change enough minds to get the treaty the two-thirds vote it requires in the Senate. The administration, meanwhile, has promised "not one dollar" of federal funding for this year's hunt.

An aide to Sen. Ted Stevens (R-Alaska), who has long championed the Pribilofs in Congress, contended that the letter was "misleading" and that the fur-seal treaty was in the best interests of the seal.

"You can't make a management decision on moral grounds," he said. "The question here is whether you consider a fur seal a person or a resource."

But the uproar over the subsidized seal kill mirrors an increasing frustration with the federal role in the Pribilofs, where the government has spent tens of millions of dollars in an effort to diversify the economy of a windswept chain of rocky islands that has been inhabited for two centuries for the sole purpose of killing seals.

In the last six years, the 760 residents of the Pribilof Islands have absorbed nearly $80 million in federal aid, including a $20 million trust fund established in 1983 to support them while they attempt to create an economy based on fishing or tourism.

The figure does not include more than $13 million in settlements made under the Alaska Native Claims Settlement Act and through the Indian Claims Commission. It does not count about $5.5 million in federal money used to buy or lease lands for national seabird refuges, or more than $30 million in state aid for harbors and other fishing facilities.

The federal government provides medical and hospital care to the islanders and it built their schools and homes and funded their sewer and electric hookups. The islanders are eligible for civil service retirement benefits (with one year of credit for each five-week seal hunt), and more than 50 are drawing federal pensions averaging $14,000 a year.

Officials at the Commerce Department, through which much of the money is funneled, defend the expenditures as an effort to do justice to the Pribilovians, who were taken to the islands by Russian fur traders. When the United States bought Alaska, the Pribilofs came along with the deal.

"The bottom line is this: The federal government is trying to do the most it possibly can to see that this transition works," said Timothy R.E. Keeney, deputy general counsel. "It's an expensive part of the world to live in."

Opponents of the seal kill do not disagree with the sentiment, but they argue that it makes little sense to support an unprofitable venture while pouring money into a search for a self-sustaining one.

"This whole argument has been about tax dollars that have been flowing into the Pribilofs," said Yvonne B. Eider of Friends of Animals.

"They haven't been able to market those skins since 1981."

Eider and other animal-protection activists are similarly unmoved by arguments that defeating the treaty will open the way for unrestricted hunting of seals. "The fishing nations would be out there sealing if it were profitable," she said. "It isn't."