DIARY: JONAH AND THE WHALE-CHASERS !

The BBC's Jonah Fisher is on a Greenpeace ship tracking the Japanese whaling fleet in the Southern Ocean. You can follow his travels for the next two months on the Ten O'clock News, and in this diary.

With Japan's whalers already likely to be starting work in Antarctic waters it may surprise you to know that the Greenpeace ship, the Esperanza is currently heading south at scarcely 8 knots - that's about 10mph on land.

Jonah cautiously wonders if the seas are officially rough yet

Minimising fuel consumption is Esperanza captain Frank's first priority.

That means running the ship on its slower but more efficient engines as much as possible.

Unlike the Japanese whaling fleet, the Esperanza cannot refuel at sea - so it's trying to save energy now to maximise the amount of time it can spend on the Antarctic ice edge. If and when the whalers are found the Esperanza can top 15 knots - but fuel consumption goes up markedly at those higher speeds.

Having chugged our way through the Roaring Forties with barely a rattle from the ship's china - the Furious Fifties have thrown us around with rather more enthusiasm.

For those like myself who are new to the Southern Ocean, mentioning that the conditions might be approaching rough is always a conversational gamble.

Having spent most of last night being tossed around in my bunk and then this morning thrown across the ship's mess food in hand, I voiced the opinion that perhaps the real Southern Ocean at last baring its teeth.

Certainly the German documentary crew thought so - they were out on deck filming the churning sea that they've been waiting impatiently for. But for the Southern Ocean veterans my comments just triggered knowing smiles and a chance to reminisce about huge waves on trips gone by which touched the ship's bridge - and to air tales of the day when one of the other Greenpeace vessels, the Arctic Sunrise rolled to 70 degrees.

Despite the relatively calm conditions on the 25th there was no sign of Father Christmas coming down the ship's chimney at the designated time.

Craftsmanship: the labour-intensive Secret Santa gift

Evidently the Southern Ocean veterans knew from prior experience that the Esperanza would prove a stocking too far - so a Secret Santa present scheme had been organised a few days previously.

I had the good fortune to receive a gift from Viktor - one of the ship's engineers.

Having worked on Russian nuclear submarines he's not your stereotypical Greenpeace volunteer. I'm told that Viktor laboured for three long evenings in the run-up to Christmas to carve me a beautiful miniature whale out of bone. And no it wasn't whale bone - though I'm glad I asked.

I felt decidedly unskilled handing over a BBC T-shirt in return.

News that the humpback whale had been spared came just 24 hours after solo yachtsman David Taylor set off on his lone protest to Antarctic waters.

Guide to the humpback Japan's point of view

A week previously I had been to speak with the 54-year-old New Zealander and do a feature on him in the eastern city of Tauranga.

David Taylor

As we sailed around the harbour in his yacht the Ann Marie, David told me that his prime motivation to go to Antarctica was the inclusion of 50 humpback on Japan's lethal research list.

Having swum with and studied humpbacks he said he had no choice but to embark on a two-month solo voyage to find the Japanese off the coast of Antarctica and make his protest. Ever since the news of the humpback's reprieve came through I have been trying to contact David to find out if he had heard the news and what it meant for his trip.

Would he be still be risking his life in the world's roughest seas now that his favourite whale had been saved? This afternoon he emailed me from his boat. "Good news about humpbacks, but at this stage I feel I should continue with protest," it said.

"Family understanding about the need to continue. Government suggested I just sail round New Zealand." At the moment the 73-metre (240ft) ship I am on is rolling from side to side as we approach the Southern Ocean. The chair I am sitting on is tied with a bungee cord to the wall to stop it sliding away.

I really like the Japanese people - it's just the whalers I can't stand David Taylor

It is hard to imagine what these treacherous waters will be like for David and his 10-metre homemade yacht.

But having spent a couple of days with him in Tauranga he is clearly not mad and knows all too well the risks involved.

To borrow some Kiwi slang, David Taylor is a yachtie.

Having built the Ann Marie himself he spends most of his time either sailing in it or building more boats. Eight years ago he competed in a race from Australia to Japan and crossed the line 65 days later in 12th and last place. This was the small matter of three weeks behind the boat that came in 11th.

In Japan, David and his crew were hailed as heroes for refusing to give up. "The Japanese thought we were great and were taking us out to dinner in all the fanciest restaurants when we arrived," he told me with a smile. "I really like the Japanese people - it's just the whalers I can't stand."

Coupled with that stubbornness of spirit is a real passion to try and act as an inspiration to get more people involved. "There's very little awareness in New Zealand about what's happening," he told me. "It's very quiet about the whaling - I hope by doing this I'm stirring up New Zealanders to take action and do something."

At the moment, David Taylor is sailing around the northern most tip of New Zealand and about to cross the Tasman Sea.

There are lots of smiles on the Esperanza this evening. News that humpbacks are being taken off this year's Japanese whale hunt had been rumoured for a few days but confirmation came just as the sun was setting.

Japan has suspend the culling of humpback whales

I am not sure if someone on board was privy to inside information but a party had already been planned for the helicopter hangar at the back of the ship.

I am told it went well. Unfortunately, the huge interest in this story meant drinking beer was the last thing on my mind.

It was more a question of working out which combination of tea, coffee and ginger nut biscuits would keep me standing the longest. The prevailing opinion on the ship is that the decision had come as a result of Australian pressure.

This week it was announced that Canberra would be sending a customs ship to the Antarctic waters to photograph and film the whalers, with a view to possibly taking Japan to court. With the Australians an important trading partner, it seems Tokyo was unwilling to allow things to slip too far.

For Greenpeace, no sooner had the news come out than it was playing down its significance. From the campaign room at the top of the ship, it was being stressed that this was just 50 of almost 1,000 whales which would still be killed.

Some 935 minke are on the list and 50 fin whales.The fins are considered an endangered species but, unluckily for them, they do not have the same sort of fan base as the humpbacks.

So, the Esperanza continues on its steady journey south. Friday was the smoothest day so far with beautiful crisp clear skies and albatrosses looping round behind the ship. On Saturday, the ship goes into port for the last time.

A two-hour pit stop in Bluff, on the southernmost tip of New Zealand, will ensure that the Esperanza's fuel tanks are full to the brim so that she can last even longer at sea.

At 0400 local time, water came racing through the rusty porthole on to the cabin floor.

After 10 days waiting for the Greenpeace ship - the Esperanza - to leave port in Auckland, my first night at sea was useful preparation for the tough conditions that lie ahead.

I'll have sea-sickness pills to hand in the infamous Southern Ocean

Luckily for me, my two room-mates quickly leapt out of their bunks and fastened the porthole shut before another wave crashed through its circular pane of glass.

Our cabin is at the very front of the Esperanza which means we hear and feel every contact between the ship's bows and the waves outside.

Technical problems with the Greenpeace helicopter delayed the ship's departure from New Zealand. The chopper is a vital part of this anti-whaling operation. Firstly, to locate the Japanese whaling fleet, and then to provide aerial video footage of the whalers' in action.

HAVE YOUR SAY The truth is that we live in a world in which humans hunt and kill animals, for recreation, food and resources. Bryan, Manchester Send us your comments

Greenpeace knows only too well that there is little point making its protest in the isolation of Antarctic waters if it does not have graphic television footage of its actions to quickly send around the world.

So there were glum faces in the Esperanza's mess when news of the ship's departure from Auckland was posted on the communal chalkboard.

"NO HELI" was scrawled underneath it - crucial parts needed for the maintenance of the helicopter had not arrived in time, so the decision was taken to leave without it. For the Greenpeace cameraman and the three-person German documentary crew - planning to film spectacular shots of icebergs and whalers from the air - it was particularly bad news.

The Esperanza is not the only ship heading to the Antarctic waters.

I am still not sure whether or not sending me on this trip is a big in-joke by BBC editors back in London Jonah Fisher

Sea Shepherd, a marine conservation group, has already made it to the ice with its ship, named after the late Steve Irwin.

But it has been forced to go north again to Australia for repairs to one of its engines.

The Australian government has also got plans to send a ship to monitor the whalers' activities.

The Japanese have been whaling under government-issued scientific permits since the moratorium on commercial whaling was introduced in 1986. But the number of whales killed has steadily risen from about 200 to more than 1,000 planned for this season.

This year, for the first time, 50 humpback whales are included. They are not just a favourite with whale-watchers, but population levels are considered to be vulnerable worldwide.

For the next two months, I'll be reporting for BBC News from the Esperanza as it journeys south down to the ice and searches for the Japanese whalers. It is no free ride. We are paying our way and, of course, I have absolute editorial independence to say what I want without fear of being taken off air or thrown overboard.

Once we reach the Antarctic ice, an elaborate game of hide-and-seek between whalers and environmentalists will begin.

If the Japanese prove better at hiding than the Greenpeace crew are at seeking, it is very possible that I may see very little and this web diary will turn into long discussions about the relative merits of passing icebergs and penguins.

I am still not sure whether or not sending me on this trip is a big in-joke by BBC editors back in London. I am certain that a colleague was only looking for a quick laugh (and found it) when they first suggested that they send a Jonah down to cover this whale story.

But, as the chuckles died away, the idea stuck and here I am preparing to cross the infamous Southern Ocean - sea-sickness pills firmly in hand.