The BBC's Jonah Fisher has been reporting from the Greenpeace ship Experanza as it tracked the Japanese whaling fleet in the Southern Ocean.
The fleet plans to kill about 900 minke whales and 50 fin whales by mid-April as part of what it describes as a scientific research programme.
Greenpeace said they were chasing the whalers who cannot hunt while being watched, but they had to abandon the chase after six weeks due to fuel shortages.
Below, Jonah Fisher and Sara Holden from Greenpeace answer your questions about Japanese whaling.
Can the Japanese explain exactly what their "Scientific research" involves? What are they researching?
Debra Jones from Oxford in England
JONAH FISHER: The best answer I have to that is to point you in the direction of the website of the Institute of Cetacean research. It's the Japanese body that overseas it's whaling programme. You can find its English site at www.icrwhale.org/eng-index.htm. In a nutshell, though, the Japanese say that their research is aimed at getting a better idea of the size and composition of the whale population in the Southern Ocean. By carrying out that research they are hoping to demonstrate that whales could be sustainably caught commercially.
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SARA HOLDEN: It's not scientific. None of the things that they want to research have to be done by killing whales, they can all be done non-lethally.
Are all the whales near extinction, or just some. If so, which?
John Kecsmar, Osaka, Japan
SARA HOLDEN: Not all whales are nearing extinction, there are some populations that are nearing extinction. Some of the whales that they are targeting in the Southern Ocean are endangered, such as fin whales. They are very slow growing and so that's one of the reasons why to try and claim that it's sustainable to hunt them doesn't stand up to scrutiny.
Would it not be more effective to mount a campaign encouraging people not to buy Japanese goods until they stop whaling. I suspect this would get the attention of the Japanese government more effectively than chasing their ships around the Southern Ocean.
Graham Bates London
SARA HOLDEN: We don't advocate a general boycott of Japanese goods because we want to make sure that the people who are pushing this particular whaling programme are the ones that feel the pressure. But what we do have running at the moment is a campaign against Canon the cameramakers because the head of Canon is also the head of the Japanese business federation and we do want to alert people to the fact that their image is being tarnished by their whaling programme. But a general boycott is not something we would advocate because it would target the people who aren't responsible. We want to target the Japanese government.
Is your real name Jonah Fisher? It cannot be true?
Iona Jefferson from Ledbury, England
JONAH FISHER: My parents obviously had a very good idea what I'd be doing 29 years after I was born.
What is preventing Greenpeace's Esperanza from refuelling back in Australia and returning to Antartica? Is the crew physically exhausted or are funds not being released from Greenpeace's HQ to refuel their ship?
Norma Caton Preston Lancashire
SARA HOLDEN: We think now is the time to put political pressure in Japan. We've started that process in the Southern Ocean and what we need to do is concentrate our resources where we will be most effective in stopping whaling for the entire season every year not just this year. It's neither a question of money or energy, it's a question of where we will be the most effective and we believe at this point having generated this amount of pressure that we will be most effective in Japan.
Greenpeace appears to lack the logistical capabilities to refuel and restock its ships at sea and consequently the whaling fleet will now be able to continue unimpeded with its hunting. Can Greenpeace put in place the necessary logistical capabilities to stay at sea for longer periods of time for next season?
Sean from Bath, in the UK
SARA HOLDEN: We took as much fuel as we could possibly carry. There is an opportunity to refuel at sea, we did that one year but this year we've decided what we need to do now is to use the pressure we've created in the Southern Ocean on the Japanese government in Japan. It's nothing to do with our logistical capabilities.
Can you shame the firms supplying the fleet with fuel? I mean the big boys in the domestic fuel market wouldn't care for it to be known that they help the whaling fleets.
BJ Nicholson Manchester
SARA HOLDEN: Well the big boys of the fuelling companies probably refuel this ship as well so that would be somewhat hypocritical but there is a big question over the refuelling vessel the Oriental Bluebird. She's flagged in Panama and doesn't have a licence to be part of the whaling fleet. We have raised that issue very strongly with the Panamanian government.
Why did the Esperanza not put itself between the tanker and the whaling ship?
Sylvia Johnson London England
SARA HOLDEN: One of the reasons we're objecting to what they were doing is that they were refuelling within Antarctic waters and there is quite clearly a risk of a spill in what is a protected area. We would not want to aggravate that by putting in a much larger ship. What we wanted to do was try and delay the process by using small inflatables without risking the environment.
What affect (if any?) did Jonah's close encounter with the humpbacks that day in the zodiacs have on him? Do encounters like that make it difficult to remain the hardened, impartial journalist, or do you have to put any emotional thoughts aside in the name of professionalism?
Jenni Barrett, Dublin, Ireland
JONAH FISHER: For me the morning when I got very close to the humpbacks was unforgettable and one of the most incredible things I've done in my life. To smell and hear the whales at such close quarters was the highlight of the trip for me. But that didn't change the reason why I had come down to Antarctica. That was to be an independent pair of eyes watching a story that is normally just recorded by the whalers and the campaigners.
I received reports that the Sea Shepherd organisation tried in vain to co-operate with Greenpeace. On a budget far less than Greenpeace's they, in my opinion, have done far more than Greenpeace to highlight the plight of the whales. Why will Greenpeace not co-operate with Sea Shepherd?
Nicki Edwards in Kent, England
SARA HOLDEN: We have a policy of non violence and non violence is non negotiable as far as Greenpeace is concerned. Sea Shepherd we believe doesn't have the same attitude towards the tactics that they use and that's why we don't work with them.
Will Sea Shepherd or the Australian Oceanic Viking be able to contunue where the Esperanza left off?
Malcolm Espley, Tattenhall near Chester
SARA HOLDEN: We expect that the same thing will happen as happened with us. That the Japanese do not want to be scrutinised and so they will not whale while the Oceanic Viking is there. And that's a good indication of the level of pressure they're under and the dramatic impact that those kind of images have on world opinion that they don't want them shown. If they're doing nothing wrong what are they hiding from?