"If the ocean dies, we all die” warns the Greenpeace and Sea Shepherd founder, now leading the Captain Paul Watson Foundation and Neptune’s Pirates charge against whale “murder”. We sat down with the veteran conservationist aboard his ship the John Paul Dejoria at Dublin’s Sir John Rogerson's Quay on Sunday.

The 73-year-old sailed to Ireland so his crew would be close enough to Iceland to stop plans “to kill fin whales this summer”.

“We are here to make sure they don’t,” said Captain Watson.

Fin whales are the second largest whale species in the world and are endangered in the North Atlantic because they were hunted commercially for their oil, meat, and baleen up to last century.

While commercial whaling was banned globally in 1986, Iceland, Japan and Norway continue to hunt the much loved species that’s vital to the health of our seas.

The Icelandic government issued a licence allowing the Halvur company to kill 128 fin whales this summer despite animal welfare concerns. Paul says the hunt may not go ahead, but added: “We are watching Iceland very carefully because although they said they are not going whaling, they might.”

If the North Atlantic whales get a reprieve, Paul told us: “Our alternative plan is to go after the world’s largest whaling ship - the Japanese factory ship the Kangei Maru which was just launched a couple of months ago.

“Right now it is off the coast of Japan but it could be in the North Pacific... this vessel was built to go long range.” Where ever it is he says his team “will go after it”.

He added: “All whaling was declared illegal in 1986 and since then about 30,000 whales have been killed illegally. We target illegal activity, that’s why we do what we do.

“The Kangei Maru is operating in violation of the International Whaling Commission moratorium on commercial whaling.

“The signatories to the International Whaling Commission could stop them but there is a lack of political motivation to uphold international conservation law.

“It is practically useless on the high seas because it has no enforcement.”

Throughout his career campaigning for animal rights and environmental protection the Amazon Peace Prize winner has had his fair share of brushes with the law, but has no plan to stop fighting to protect our seas.

He said: “We’ve been shot at, we’ve been rammed at, we’ve been beaten. I am sort of used to all that stuff. I was shot down in Antarctica but I had a Kevlar vest on.

“It’s not risk free and... we weather an awful lot of horrendous storms and ice conditions but to me it’s all part of the whole thing. It’s an adventure.

“All my life people keep saying you are going to get yourself killed but I’m 73 and still here.

“My primary issue is stopping whaling,” he added.

“But the problems range from whaling to plastic pollution, chemical pollution, noise pollution, overfishing, illegal fishing... on an on.

“People should be concerned because if the ocean dies we all die. It’s as simple as that.

“Since 1950 there’s been a 40% diminishment in phytoplankton... [it] provides 70% of oxygen in the air we breathe and sequesters enormous amounts of C02. If phytoplankton were to disappear from the sea, we all die.

“All over the world commercial fisheries are collapsing because of greed.

“Fewer and fewer fish means its harder to catch them so you have to invest in $150 million ships with satellite technology.

“Fish prices go up relative to scarcity, so scarcity translates into demand which puts the prices up and more money is being made.

“I call it the economics of extinction.

“There should be a complete restriction on heavy gear, all these nets, all these long lines,” he added.

“A good 40% of plastic debris [in oceans] is from the fishing industry.”

Cork man, Trevor Kennedy, was volunteering on the John Paul Dejoria when we visited on Sunday.

He told us: “I joined the Captain Paul Foundation to help save the whales, save the planet and hopefully we’ll be able to pass it onto the next generations.”

Eve Turkington from Belfast leads the Northern Ireland chapter of the foundation and says she joined because she loves the ocean and wants to protect it.

“Whenever you open your eyes and see what’s happening in Iceland and the Pharaoh Islands [Grind] it’s time we made a change.”

The John Paul Dejoria is due to set sail from Dublin later this week.