As a Mariner. I am amazed the Coast Guard has not yanked the Captains License. Although I am against whaling and killing Dolphins.
The Irwin flies under the Dutch flag and the harpoon interceptor flies under either the Aussie flag or New Zealand flag (can't remember off the top of my head).
And Australia claims the waters that the Japanese hunt whales. Technically they are in international waters so really there is no authority. Sea Shepherd believes they are the coast guard.