The following script is from "Return of the Humpbacks" which aired on Oct. 20, 2013. The correspondent is Scott Pelley. Robert Anderson and Daniel Ruetenik, producers.
We very nearly lost one of the wonders of the world. The humpback whale was efficiently slaughtered until there were only a few thousand left. But in one of the great success stories in conservation the humpback is making a comeback. It's a good thing too because what we've learned about them lately makes the humpback one of the most fascinating animals ever to grace the Earth.
There are many species of whales and one by one they're coming off the endangered species list. Whale hunting is rare today but there is still a place on the high seas where there's a battle to eliminate the last vestiges of whaling. There we found a man who has risked life and limb to end any threat to whales once and for all.
You're watching the ramming of a Japanese whaling ship by a combative conservationist group, lead by American Paul Watson. He's trying to stop the transfer of a minke whale the Japanese just killed to the factory ship that will cut it up.
Commercial whaling is banned by international agreements. But the Japanese and a few others are still launching harpoons. These scenes were shot for the Animal Plant series "Whale Wars" -- and these scenes were shot by the whalers themselves who say this is evidence that Watson is nothing more than a pirate. The Japanese obtained an international arrest warrant for him. So, for the last year, this conservationist, or pirate, has lived on the world's oceans unable to set foot on land.
Scott Pelley: We are headed out to international waters where Watson lives on a ship beyond the reach of the law. But before he would meet with us, we had to agree that we wouldn't say where we are, or even what ocean this is. Suffice to say it involved several airplanes and many thousands of miles.
Towards the end of that journey, Watson sent this trimaran to pick us up. This boat once set the speed record for circumnavigating the Earth. He named the boat for an actress who's a supporter. But to us it looked more Darth Vader than Brigitte Bardot. Watson came to the Bardot from a floating hideout that we agreed not to show. He is one of the founders of Greenpeace. And now at the age of 62, he calls his new armada: Sea Shepherd.
Paul Watson: The simple fact is this, if the oceans die, we die.
Paul Watson: Sea Shepherd was set up to uphold those international laws and regulations protecting our oceans.
Scott Pelley: But why is that your job? Countries enforce laws. Why are you doing this?
Paul Watson: I just do not see the political will on the part of these governments to do anything.
Scott Pelley: But that makes you a vigilante. You're deciding on your own that you're going to enforce these laws. What gives you the right?
Paul Watson: Because I want to survive. And I want to make sure that my children survive. And I'm not going to sit back and watch the oceans be destroyed because governments don't have the political or economic will to uphold these laws.
The whaling ban makes an exception for research. And the Japanese proclaim that exception in tall letters on their ships. They set their own quotas about 900 minkes, 50 fin whales and 50 humpbacks. These are minkes. And even though the Japanese reserve the right to kill humpbacks, they haven't, according to the International Whaling Commission.
Paul Watson: There is no scientific basis for what they're doing. We have seen them take a whale onto the factory vessel. There's no scientist there. There's nobody measuring anything. They simply cut them up, send them down below, and package them. This is not science. It's bogus.
The International Court of Justice in The Hague will be deciding whether Japan's whaling is really for research or should be stopped. But while the whaling continues, Sea Shepherd fouls the Japanese plan with rope to catch their propellers. The Japanese fire back with water, and ear-splitting sirens. Sea Shepherd throws stink bombs. The Japanese return concussion grenades.
Scott Pelley: You called Sea Shepherd, which you founded, the most aggressive, no-nonsense conservation organization in the world. And you said, quote: "I don't believe in protests. That is far too submissive." What do you mean?
Paul Watson: Well protesting is sort of like, "Please, please, please, don't do that." But they'll do it anyway. But they just ignore you. So, protest is submissive. We're not a protest organization. We're an interventionist organization. We intervene against illegal activities.
But this is what happened recently when Sea Shepherd tried to intervene. The whaler kept coming and sheared the bow off Watson's $2 million boat which eventually sank. No one was seriously hurt. Watson claims he has cut the Japanese catch. Because of these tactics, the same tactics that the Japanese say are illegal.
Scott Pelley: You're in sort of a prison, aren't you?
Paul Watson: Well it's a pretty nice prison. It's you know-- I don't mind being on the ocean.
Scott Pelley: But when people call your tactics violent, how do you respond to that? I mean, you look at this footage, it looks violent. It's hostile.
Paul Watson: The Japanese are committing violence against living whales. We are not hurting anybody so we're not violent.
This battle is fought in the last place where humpback whales are considered "endangered" by the international agency that decides these things. These "South Pacific" humpbacks feed here in the Antarctic summer then journey north 4,000 miles to mate. This is where much of the research is done around a speck on the map called Rarotonga.