TOKYO (AP) _ The mother ship in Japan's controversial research whaling fleet returned home to a quiet welcome Monday after a four-month hunt in the Antarctic, where it dodged protesters' boats to kill 241 whales.

About 20 whaling officials and Parliament members greeted the Nisshin Maru No. 3's 120 crew members at a ceremony on its long main deck.

''Your whaling is crucial for maintaining Japan's food culture,'' Tatsuo Shinmori, a Parliament member, told the crew. ''You struggled against the protesters, and now we should follow your example by doing our best to protect whaling.''

Stored beneath the ship's 23,000-ton deck was the meat from 241 Minke whales, already processed by a shipboard factory. Scientists estimate stocks of Minke whales at between 400,000 and 700,000.

In the early 1960s, whales provided 23 percent of all meat consumed in Japan. But declining supplies have turned it into a delicacy, and the Nisshin Maru, with its rusty, paint-marked sides, is the only remaining mother ship.

Japan, still the world's largest consumer of whale meat, officially stopped whaling commercially in 1987, following a worldwide ban by the International Whaling Commission.

But the ban allows so-called research whaling, under which countries can capture whales to test stocks, then may consume the meat. The research is to see whether there are sufficient stocks of some species to allow limited commercial whaling when the ban is re-evaluated in 1990.

International environmental groups such as Greenpeace have charged that Japan is using the research provision as a ploy to continue whaling, and that alternative non-lethal research methods are available.

Greenpeace members used a ship and rubber rafts to try to block the Nisshin Maru and its three catcher boats from whaling in the Antarctic waters, and collided once with the mother ship.

''There's a basic difference between us in ideology and philosophy - they want to protect all whales - so a conflict is inevitable,'' said Hidehiro Kato, director of research on the Nisshin Maru.

''I'd prefer to use non-lethal methods, but they don't tell us age, reproductive status or condition of the whales,'' he said. ''At this point, the best approach is a combination of lethal and non-lethal research.''

Japanese whaling officials initially said at least 825 whales had to be caught each season to make the research program scientifically accurate. But following strong international opposition, they reduced this year's goal to 300.

Kato said the fleet did not reach the goal primarily because of bad weather, but that the Greenpeace protests ''had some effect.''

Crew member Hideyoshi Yoshida said he was in a catcher boat that narrowly missed being hit by the Greenpeace ship.

''The research whaling was approved by the Japanese government, so I wish people opposed to it would discuss it with the government, rather than confronting us while we're whaling,'' he said.