Ocean Raider: Defenders of the Wild (1993)

On the high seas, beyond the reach of the law, the ships that illegally kill whales, dolphins and seals can do so with little fear of punishment. But there is one sight that they have learnt to dread: the black pirate flag of the Sea Shepherd Conservation Society. 'Set a pirate to catch a pirate', is founder Captain Paul Watson's motto and for twenty-five years he has put those words into action. This film follows the exploits of Watson and the crew of two of Sea Shepherd's vessels, as they sails thousands of miles across the North Pacific to confront the drift-netting fleets of Taiwan, Japan and South Korea. The voyage culminates in a dramatic dawn attack on Japanese driftnetters and bring the armed intervention of US Coastguard cutters and patrol aircraft. Watson is rightly proud that, in all their actions, no-one has ever been injured. But can he justify putting fishermen and whalers out of work?

IMDb