The Japanese whaling fleet left port in mid-November

In November the Japanese whaling fleet set sail for waters off Antarctica to begin its annual hunt.

Over a six-month period, it will kill 1,000 whales as part of what it says is a scientific research programme.

Western nations and environmental groups have roundly condemned the move, calling the programme a front for commercial whaling.

But deputy whaling commissioner Joji Morishita told BBC News that Japan's position was hugely misunderstood.

What drives Japan is a belief in the principle of sustainable use of resources, whatever they might be, he said.

"Many countries support sustainable use of resources, but somehow they exempt whales from this principle, because they think whales are a special animal.

"But there are many special animals - the cow in India, for example - and if each nation tries to impose its own special animal on other countries, you can see the problem."

Sometimes issues of science and principle might be more important than simple issues of emotion Joji Morishita

Whales should be treated just like any other resource, he said, but this does not mean that Japan would act irresponsibly.

"We are not saying that we want to utilise endangered or depleted species.

"People say they want to preserve whales for future generations and we agree. We want to preserve whales as a resource, so we have a mutual goal."

And Japan's research programme is about fulfilling this goal, he said.

"The reason for the moratorium [on commercial whaling] was scientific uncertainty about the number of whales.

"It was a moratorium for the sake of collecting data and that is why we started scientific whaling. We were asked to collect more data."

'By-product'

This year, the programme will involve killing more than 900 minke whales and 50 fin whales - meat from which will end up canned, in school dinners or on the menu in restaurants across Japan.

The mission was also due to kill 50 rare humpback whales, but Japan has now backed down on this in response to international pressure.

"Whaling and whale cuisine are part of Japanese culture, but the purpose of the research programme is science," said Dan Goodman, councillor to Japan's Institute of Cetacean Research.

Japan says its hunt is too small to affect whale populations

"The fact that the whale meat - which we call by-product - is sold is because the International Convention for the Regulation of Whaling specifically requires that the by-product of research be processed.

"It is a legally binding obligation."

The ultimate aim of the research, he said, was a properly managed resumption of commercial whaling.

"It is just like any fisheries - tuna, salmon, for example - the proper way to conduct the fisheries is to do the science to work out how best to manage the resources."

Mr Goodman rejected criticism that the same research data could be obtained using non-lethal techniques.

"More than 100 measurements and samples are taken from each whale and there are some bits of information that you can only get from lethal research."

"For example, you need ovaries to determine pregnancy rates, which you can't get by simply observing these animals."

'Issues of principle'

Japanese officials are aware that, in some countries and among environment groups, anti-whaling sentiment is running high.

"It would be good if we were not causing any bad feelings," said Mr Morishita.

"But sometimes issues of science and principle might be more important than simple issues of emotion, especially if they are based on misunderstandings.

"We need to spend more energy on giving a balanced picture of this issue."

They condemned environment group Greenpeace and the more radical Sea Shepherd, both of whom are pursuing the fleet with the intention of disrupting its hunt.

"These ships are involved in very dangerous illegal activities and so I have to ask them to stop their illegal activities immediately," said Hideki Moronuki, chief of the whaling section at the Fisheries Agency of Japan.

"Last year Sea Shepherd rammed a ship, two years ago Greenpeace did, although Greenpeace insisted it was our vessel that moved."

Two crew members were also injured when Sea Shepherd activists threw bottles containing acid at them, he said.

The fleet was taking action to escape from the ships to avoid a repeat of past dangerous incidents - action that was disrupting its research.