Japan promised today to end all commercial whaling in 1988 if a U.S. federal appeals court rules that the United States may suspend antiwhaling penalties required by U.S. law.

The announcement marked the first time Japan has committed itself publicly to bring to a close a centuries-old industry whose preservation had been almost a point of national honor.

The decision, adopted in a Cabinet meeting today, followed lengthy negotiations with Washington, which had threatened to cut Japan's fishing quotas -- worth about $462 million annually -- in U.S. territorial waters unless the 1988 ban was adopted.

The decision was not formally linked to tense negotiations over bilateral trade now under way between the two countries, but Japanese officials see it as a major concession in the total picture of ties with the United States.

Foreign Minister Shintaro Abe is to send a letter to U.S. Commerce Secretary Malcolm Baldrige formally conveying Japan's intentions.

The move was denounced immediately by the Japan Whaling Association, whose members "harvested" 4,600 whales in the 1982-83 season. President Motonobu Inagaki, blaming a rise in the international antiwhaling movement, said he was "disheartened" by it and that the government should compensate the industry.

Some private companies, meanwhile, were reported to be contemplating suing the Japanese government over the decision.

Government officials were also displeased. "The majority of the Japanese people are in favor of continuing whaling," said Susumu Akiyama, director of the Foreign Ministry's fisheries division.

In the 1950s, whaling was a major industry, employing directly about 15,000 persons. Today, it has shrunk to about 1,300 jobs, with only a single mother ship and fleet. Whale meat, once a major source of protein in Japan, has become a delicacy.

Japan has argued that whaling makes economic use of the carcass, does not threaten the survival of a species and is an important aspect of Japanese culture. It ridicules moral objections to whaling, noting that they often come from industrialized societies where much beef is consumed.

In 1981, the International Whaling Commission called for a total ban on whaling starting in 1986. However, countries were able to exempt themselves legally by filing formal objections to the ban, as Japan did.

Japan also filed an objection to the commission's leveling of a zero quota on sperm whales for the current season, and Japanese whalers continue to hunt them.

Negotiations with Washington began because of U.S. laws that require retaliation against countries that do not follow fishery agreements such as the International Whaling Commission ban.

The Packwood-Magnuson Amendment calls for the United States to cut quotas for fishing in U.S. territorial waters by 50 percent and then altogether for such countries.

Last fall, the United States and Japan discussed a deal whereby the United States would not invoke its sanctions if Japan agreed to end whaling in 1988, two years after the International Whaling Commission's moratorium is scheduled to go into effect.

Japan agreed to the deal for all types of whales, according to U.S. negotiators. However, Japan publicly contested that, saying it had agreed only for sperm whales. In December, Japan filed papers with the whaling commission withdrawing its objections for sperm whales, to be effective April 1, 1988.

Talks continued with Washington over a ban on all whaling. Today Japan announced it agreed, but only if the United States won a lawsuit that environmentalists had filed in the meantime.

The plaintiffs, including Greenpeace USA, were angered that the deal allowed Japan to go on hunting the sperm whale in violation of the whaling commission's zero quota. They contended that Washington had no right to make such a deal.

Last month, a U.S. District Court judge in Washington ruled in favor of the plaintiffs, ordering the government to begin applying the sanctions. The United States appealed. A decision is expected this summer.

[In Washington, a spokesman for Greenpeace called Japan's announcement "a public relations ploy" rather than a binding commitment.]

Japan's announcement today effectively conveys the message that if the United States cannot meet its side of the bargain -- the withholding of the sanctions -- Japan will not be held to its obligations, either.