Crew members aboard the Sea Shepherd vessel the Bob Barker react as the Japanese whaling vessel Yushin Maru 3 crosses close to its bow during a six-hour-long ordeal at close quarters in the Antarctic in 2014. (Simon Ager/Sea Shepherd Australia/Reuters)

Every year, Japanese boats with the word “RESEARCH” stenciled on the side head to the Southern Ocean to hunt for hundreds of whales. And every year since 2005, Paul Watson has used pirate-like tactics to try to stop them.

The ships of Watson’s Sea Shepherd Conservation Society nestle up to the back of the large Japanese factory boats that winch whale carcasses up a ramp for processing. Staying so close, Watson says, is a risky but nonviolent way of preventing the vessels from hauling in whales.

“We thought the best way to do this was to intervene directly,” Watson told The Washington Post. He and other international critics say the whales aren’t killed for research at all. “We block their ability to load dead whales and if we do that, they can’t hunt.”

But now, Sea Shepherd is stopping.

The organization said the Japanese have used military-grade satellite tracking to evade Watson’s whale-hunt-ending ships, which simply can’t get close enough.

In the past two years, Watson said, his organization’s ships have only caught glimpses of the Japanese whaling vessels.

“Every time we approached them, they would be just over the horizon,” he told The Post. “They knew where we were at every moment. We’re literally wasting our time and our money.”

It amounts to about $4 million per expedition, nearly a third of the nonprofit’s total yearly budget. And that wasted money could be better used to protect other marine animals around the world, Watson said, instead of endlessly chasing Japanese whalers.

The nonprofit group has been operating in the oceans near Antarctica since 2005, when it took the Farley Mowat, a “battered and slow vessel” out to thwart whalers, according to a news release.

Over the years, they added five other vessels, including one named after “Crocodile Hunter” Steve Irwin, and they claimed more and more successes.

At the same time, they’ve been engaged in other efforts to prevent poaching and illegal fishing across the globe. The battles aren’t just at close quarters in the high seas but are also in international courts of law.

[Feds review annual whaling quotas for Alaska Native hunters]

Watson said one judge deemed him a pirate because of his tactics. Over the past 40 years, Sea Shepherd has engaged in embargoes and sunk several ships in the 1970s and 1980s. That was decades ago, Watson said, but he conceded that even blocking the whaling vessels involves dangerous maneuvering at close quarters.

Watson was one of the founding members of Greenpeace in 1969, but was expelled seven years later for what the organization deemed violent actions. He said he took a club away from a man who was attacking baby seals.

A Post story in 1979 dubbed him the “angry shepherd of the seas.”

“People sometimes say I have a suicide complex,” Watson told The Post’s Henry Mitchell for that story, which detailed his attempt to get between whalers’ harpoons and their intended target. “Well, in fact I enjoy being alive, more than most people. But people can’t believe a man will risk death to save whales. That’s what they can’t understand. So they think I’m crazy or that I attach no value to my life.”

Watson conceded there’s an air of oceanic vigilantism to what he does, but he told The Post that in his four decades of protecting sea animals, no one has been killed or injured. And he believes some of the people he’s trying to combat are violating international laws. The rest, he said, are just outright poaching. He described Sea Shepherd as an “interventionist anti-poaching organization.”

“Our opposition are criminals,” he said Tuesday. “These people are operating against the law. We shouldn’t be out there doing this. The governments of the world should be doing this. We would gladly step aside if they would do what they’re supposed to be doing.”

The legalized whaling is particularly vexing, Watson said, because the Japanese say they are killing the animals in the name of research.

As The Post’s Rachel Feltman wrote in 2015: “Most of the whales won’t end up in laboratories, but on dinner plates. Japanese officials claim that the specimens will be used to study the health and migration patterns of minke whales, but some argue that these research vessels have never been anything but a way around commercial whaling bans imposed in 1986.”

Even then, Wired wrote in 2015, only a small percentage of Japanese eat whale meat. The magazine cited a 2006 poll conducted by the Nippon Research Center that found that 95 percent of Japanese people very rarely or never eat whale meat. And the amount of uneaten frozen whale meat stockpiled in Japan has doubled to 4,600 tons between 2002 and 2012.

And the Japanese government spends about $50 million a year to heavily subsidize whaling, according to National Geographic. The staunchest advocates say it is a centuries-old tradition — and that no outside nation or international treaty should be able to tell the sovereign nation what it can hunt.

“And just as the whale has become symbolic for environmental groups like Greenpeace, it has, in response, become symbolic for the Japanese, too,” Wired wrote.

Kazuhiko Kobayashi, an agronomy professor, told the magazine that the “strong condemnation of whaling by the foreigners is taken as harassing the traditional values.”

While Watson’s role in the conflict has been paused, he emphasized that his group isn’t abandoning whales in the south seas. They’re simply trying to be practical as they figure out a better way to do it.

They still claimed a victory of sorts, having saved whales for a dozen years, and shined a light on whalers’ practices.

“The Japanese whalers have been exposed, humiliated and most importantly have been denied thousands of lives that we have spared from their deadly harpoons,” a statement from Sea Shepherd said. “Thousands of whales are now swimming and reproducing, that would now be dead if not for our intervene.”

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