Whaling vessels left a western Japan port on Thursday to conduct what Tokyo calls "research whaling" in the Antarctic Ocean for the third time since an international court ruled against the practice in 2014.
Two vessels set sail from Shimonoseki, Yamaguchi Prefecture, on a mission to catch 333 minke whales through March and collect scientific data necessary to manage whale stocks and the ecosystem in the Antarctic, according to the Fisheries Agency.
They will join the 8,145-ton mother ship Nisshin Maru and two other ships departing from different parts of Japan before heading for the far south.
The International Court of Justice ruled in 2014 that Japan's whaling program was "not for purposes of scientific research" and ordered its suspension. Japan in response submitted a revamped plan to the International Whaling Commission, capping the number of catches to a third of what it was.
Based on the new plan, Tokyo resumed whaling in the Antarctic Ocean the following year.
Japan has been catching whales in the region for "scientific research" since 1987. But the program has drawn criticism with conservationists condemning the activity as commercial whaling in disguise, since the whale meat is sold on the open market in Japan.
Conservationist group Sea Shepherd said in August it is abandoning its annual antiwhaling activities in Antarctic waters, citing increased use of sophisticated technology by Japanese whalers.
The group had previously disrupted and interfered with the whale hunting operations of Japanese ships.