Although born in Tokyo, ''Hana'' describes herself as being a ''citizen of the planet Earth''. She's deliberately keeping it vague. She agreed to be interviewed only if her real name, age, regular occupation or any detail that may identify her be kept private.

Hana has volunteered because she feels ''disgusted and ashamed'' of the Japanese government. ''Overconfident, arrogant, illegal and altogether unacceptable,'' is how she describes its stance on whaling. ''A complete sham'' is what she calls the Institute of Cetacean Research, which carries out the annual whale hunt in the Southern Ocean in the name of research. Having made these criticisms publicly in her blog, Hana must remain anonymous because in Japan if you speak out against the status quo you will be, she says, ''hammered back down like a nail''.

She knows of other environmentalists in Japan who have been subjected to campaigns of harassment - their family businesses and homes targeted with graffiti and loud-hailer abuse, their children bullied and ostracised at school.

Hana is on board Sea Shepherd's newest vessel, the SSS Sam Simon, in Antarctica as part of its Operation Zero Tolerance campaign, intending to stop Japanese whaling.

This is Sea Shepherd's biggest offensive yet, with the Sam Simon being one of four ships backed up by a helicopter and three drones and more than 100 crew.

Hana's role and that of another Japanese volunteer on board is even more critical than usual to the group's success.

In what has been described as a propaganda victory, the marine conservation group actually purchased the ship, renamed the Sam Simon, from the Japanese government without it realising who it was selling it to in September. As a result, everything on board is labelled in Japanese, which is where the other Japanese volunteer translator, ''Briggsy'', comes in.

Briggsy says whale meat was once a common staple in Japan, and whaling was held in high regard. For her mother's generation, whalers were considered heroes for bravely crossing the oceans.

''After the war there was nothing to eat in Japan, [a whale] could feed a lot of person,'' she says. But the food culture in Japan has changed significantly in the past 50 years and this is no longer the case, she says. ''People don't eat the whale meat because now it is very expensive and it's like a high-level cuisine.''

Despite this, whaling continues. Hana says this is primarily due to greed and bureaucracy, and also because the Japanese, like any country, don't like being told what to do by other countries.

The whaling fleet left Japan for the Southern Ocean in late December, planning to catch up to 935 Antarctic minke whales and up to 50 fin whales. Tokyo claims it catches whales for scientific research - a loophole in the international ban on whaling - but makes no secret of the fact that they ultimately end up on dinner plates.

In Japan, public perception of the issue is ''very manipulated by the media'', says Briggsy. ''There are a lot of Sea Shepherd haters online,'' she says, adding that the organisation, which is an international one, is often considered exclusively American.

Hana says the Sea Shepherd crews are routinely depicted as eco-terrorists, yet the aggressive actions of the whaling fleet, such as their use of potentially fatal water cannon and stun grenades, go unreported. ''Unfortunately, Japanese media do not tell the truth when it comes to whaling,'' she says. ''If Sea Shepherd is as bad as the Japanese media tells me, I would not have joined.''

It was the bravery of other activists that first inspired Hana a few years ago, and speaking with her it is clear just how much courage it has taken for her to become involved. Despite the personal risk, she joined ''because Sea Shepherd saves lives''.

Hana can usually be found in the mess, blogging in Japanese and English, for the Sea Shepherd website. Her other role on board, as it was during last year's campaign when she was on the Bob Barker, is to translate any radio communication with the whaling fleet.

Briggsy, nicknamed that by the engineers, is on her first campaign. ''One of the biggest challenges we've had in the engine room is the lack of English,'' says chief engineer Campbell Holland of the new ship. Key items such as control panels and manuals remain in the original language. ''All the information is there, really methodically ordered and everything, it's just unfortunately unreadable.''

Briggsy began the process of re-labelling in November. ''In the past I used to translate, but small things, not a ship, for example,'' she says.

On their anti-whaling expeditions, Sea Shepherd usually has a translator on board but experience has taught it to protect the identities of Japanese volunteers. ''For their safety, or at least for their families, it's better they're not easily identified,'' says Sam Simon Captain Luis Manuel Pinho.

Briggsy believes public knowledge of her position would damage her future job prospects and potentially lose some friendships. But she is more concerned about protecting her family. ''I'm not the only person who carries this name,'' she says. ''I don't want to make problem to them for my personal choice.''

Hana has similar concerns, but in being able to talk directly to Japanese people through her blog hopes to educate and stimulate more public discussion to change things. ''I want to be the bridge between Sea Shepherd and the Japanese people so that, together, we can end Antarctic whaling forever,'' she says.

Hana also raises a new point for Australians opposed to whaling. West Australian government plans to build a gas facility and sea port for the Kimberley region in the middle of the world's largest humpback whale calving area could be as detrimental to the whale population as the Japanese whaling fleet.

''If you are against Japanese whaling, why not stand up for Kimberley as well? Same whales. Die by harpoon or die by gas plant-related issues, what's the difference?''

With AFP