CANBERRA: The futuristic anti-whaling protest boat struck by a Japanese harpoon vessel near Antarctica finally sank Friday, prompting Australia to voice official concern about safety in the remote Southern Ocean.

Senior diplomats in Tokyo made “high-level representations” about safety in Antarctica’s frigid waters. They also raised concerns about “spy flights” organized by Japanese whalers from Australian airports to track and foil protesters, Australia’s Environment Minister Peter Garrett said. Canberra, he said, was also keeping open the option of an international legal challenge to Japanese whaling if diplomatic negotiations with Tokyo failed to reach an outcome.

“If we don’t see substantial and significant achievement in respect of those negotiations, and if we don’t see it by the time the International Whaling Commission meets in June ... then the consideration of legal action will be one that will be fully in front of us,” Garrett told reporters in Sydney.

The hard-line Sea Shepherd Conservation Society’s powerboat Ady Gil sank after having its bow sheared off in a collision with the Japanese security ship Shonan Maru No. 2.

Each side has blamed the other for the incident in which one crewman aboard the protest vessel was injured. “We strongly protest actions that obstruct the course of Japanese vessels, or those that threaten lives and properties and are extremely dangerous,” Japanese Foreign Minister Katsuya Okada told a news conference on Friday, adding it may be necessary to talk with other governments to prevent this from happening again.