A U.S.-based marine wildlife conservation organization declared a "victory" in making the Antarctic Ocean a whaling-free zone after Japan announced its withdrawal from the International Whaling Commission to resume commercial catches in its economic zone in July.

"Sea Shepherd's objective of ending the slaughter of whales in the Southern Ocean Whale Sanctuary has been realized," the Sea Shepherd Conservation Society said in a statement Wednesday. Japan has caught whales in the Antarctic Ocean for what it claims are research purposes, but states that aren't part of the IWC are banned from conducting research whaling there.

Paul Watson, the organization's founder, said, "We look forward to continuing to oppose the three remaining pirate whaling nations of Norway, Japan and Iceland."

At the request of Japanese authorities, the International Criminal Police Organization has issued an international wanted persons alert for Watson in connection with two incidents that took place in 2010 against a Japanese whaling ship in the Antarctic Ocean.

The Sea Shepherd, which describes its activism as "innovative direct-action tactics" that "confront illegal activities on the high seas," has intervened in Japanese whaling in the Southern Ocean Whale Sanctuary since 2002, according to the nonprofit organization. In 2012, a U.S. appeals court ordered the group's activists to cease "physically attacking" and interfering with Japanese vessels in the Antarctic Ocean.