In recent weeks it has often looked as if the entire marine world, or at least their self-appointed guardians, was ganging up against Japan. The country is under fire for catching and eating whales and dolphins and this week an international body considered outlawing the trade in Atlantic bluefin tuna, a key ingredient in sushi.

Thus many Japanese took a kind of vicarious pleasure when the Japanese whaling ship the Shonan Maru 2 docked last week in Tokyo and discharged a prisoner, one Peter Blethune, 44, of New Zealand. Blethune had allegedly climbed aboard the Japanese ship to make a "citizen's arrest" of its skipper. Instead, he was detained and brought back to Japan, where he faces charges of "international trespassing."

On docking he was turned over to the Japanese Coast Guard which deployed about 100 guardsmen to escort him to a place of detention. Dozens of newsmen and television cameramen were on hand to record the event, and a small contingent of protestors proclaimed that the ban on commercial whaling is an affront to Japanese culture and sensibilities.

Throughout the three-month whaling season in the southern waters off Antarctica that runs from November through January, Japanese television viewers have been treated to almost daily scenes of confrontations at sea between Japanese whaling factory ships and vessels belonging to the Sea Shepherd Conservation Society.

Protests by environmental groups about Japanese whaling operations are nothing new, but the Sea Shepherd group is particularly aggressive. There have been almost comical, though deadly serious, sea "battles" with the Sea Shepherd people spraying the whalers with paint and the whalers retaliating with water hoses. There have also been collisions at least one sinking.

Phil Warden, head of the Sea Shepherd group based in Hobart, Tasmania, said of Blethune's arrest, "He may be a criminal in Japan but he is a hero in Australia and New Zealand." Australia's Prime Minister Kevin Rudd's government supports the Sea Shepherds and has promised to take Japan to the International Court of Justice before the next whaling season should Japan continue whaling. (That assumes he gets re-elected.)

Japanese Foreign Minister Katsuya Okada complained about Australia's open support of the conservation group and its tactics. "Sea Shepherd's interference with our country's whale research program has been extremely pernicious," he said. Japan is allowed by the international Whaling commission to catch up to 1,200 minke whales a year for supposed scientific purposes.

But as if dramatic opposition whaling were not bad enough, Japan is taking a hit from Hollywood too. A 2009 American documentary film, The Cove, this month won an Academy Award for the best documentary. The film graphically depicts the annual killing of dolphins in Taiji, a small coastal town in Wakayama prefecture south of Tokyo.

The villagers are shown corralling the migrating dolphins (and whales) and driving them into a cul-de-sac (the Cove), where they are netted and then killed by fishermen in small boats using knives and spears, a process known as drive hunting. Some surviving dolphins are sold to aquariums and sea shows.

The documentary has only been shown at two small venues so far in Japan. One was a showing at the Foreign Correspondents' Club and another at the 2009 Tokyo Film Festival. Medallion Media acquired the rights to distribute the film generally in Japan and hopes to screen it beginning in April.

But it remains to be seen whether many cinemas will choose to do so. While there is no official censorship in Japan, books and films that portray Japan in a bad light, such as those discussing the Rape of Nanking, often find it hard to find publishers or distributors.

Many in Japan argue that wide spread opposition to whaling and dolphin hunting is a kind of cultural imperialism, an attack on a traditional way of life that it an intimate part of what it means to be Japanese. Westerners raise and slaughter cows and sheep for their meat, why shouldn't Japanese eat sea-going mammals as well, they argue?

In fact, relatively few Japanese eat whale (or dolphin) meat, and it is hardly a staple of Japanese culture except perhaps in a declining number of fishing villages, such as Taiji, with long traditions of whaling. It is probable that millions of urban Japanese go their entire life without once tasting whale meat or even wanting to give it a try.

There are no Michelin Guide-starred whale food restaurants in Tokyo as there are for other Japanese restaurants serving aquatic delicacies such as sushi, fugu and eel. And even Taiji recently took dolphin meat off local school lunch menus because by eating it children might consume an unhealthy dose of mercury.

The Asahi Shimbun newspaper recently cautioned against Japanese pushing the culinary culture argument to defend whaling too strongly. "What's happening is that people who eat other animal meats are criticizing whale eating as cruel, while Japanese, who actually seldom eat whale, are claiming that whale eating is a part of Japanese culture. That's an odd spectacle."

But if whale and dolphin flesh is not really part of Japanese culture, the same can't be said of tuna. "Everybody eats tuna," says Setsuko Fujimoto, a suburban housewife. "They might like other fish types with their sushi, but they always have tuna." Indeed, tuna is the centerpiece of any sushi-sashimi dinner, which really is a distinctive Japanese culinary cuisine and recognized as such around the world.

So it is hardly surprising that Tokyo pulled out the stops to short circuit an international ban on the trade in Atlantic Bluefin Tuna. Such a proposal was considered but defeated late last week before the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) meeting in Doha and voting on the ban on March 25.

The ban was proposed by Monaco but is supported by the United States and other major countries in the European Union. Japan is worked hard to win votes among developing nations of the 175-member group, especially among those highly dependent on Japanese developmental assistance. But it also garnered support from Asian neighbors, including South Korea, China and, interestingly, Australia.

Japan imports 75-80 percent of the Atlantic bluefin catch, which some think makes the best sushi ingredient. A ban on the commerce would not be the end of for tuna aficionados. There is Pacific tuna and the possibility of harvesting the tuna in fish farms.

But shutting off the supply of one important variety would likely to raise the price of tuna - and of sushi itself - which can be pretty pricy as it is. The mammoth fish can fetch as much as $100,000 at the world famous Tsukiji Market in Tokyo. And just one slice of tuna-tipped sashimi can run as much as $20 in a upscale Ginza sushi restaurant.

Japanese breathed a temporary sigh of relief when the trade ban was defeated, but they remain worried that it might be renewed and spread to pacific Tuna. If that happens, warned Fumihiro Ozawa, vice chairman of a group of tuna wholesalers, "Japan's food culture will collapse."