Japanese vessels left Friday to conduct what Tokyo calls “research whaling” in the Antarctic Ocean through March.

Japan is planning to hunt 333 Antarctic minke whales in its second whaling expedition in the Antarctic Ocean since an international court ruled against the practice in 2014, the Fisheries Agency said.

Responding to the International Court of Justice ruling, Japan submitted to the International Whaling Commission a new whaling plan to cut catches of minke whales by two-thirds to 333.

In fiscal 2014 through March 2015, the country only conducted visual surveys but resumed whaling based on the new plan the following year.

Nonprofit organization Sea Shepherd Australia has expressed its intention to block Japan’s whaling, and the agency is planning to monitor the group’s activities from one of its patrol ships.

Two whaling vessels — the 724-ton Yushin Maru and 747-ton Yushin Maru No. 2 — left the port in Shimonoseki, Yamaguchi Prefecture, on Friday morning. They will soon join two other whaling ships and the 8,145-ton mother ship Nisshin Maru to form a fleet with 185 crew members in total.