The Nisshin Maru, the mother ship of Japan's whaling fleet, left Innoshima port in Hiroshima Prefecture on Thursday, presumably to participate in the annual hunt in the Antarctic Ocean, Greenpeace Japan said.
Greenpeace sent staff to Innoshima to witness the Nisshin Maru leave port, the group's secretary general, Junichi Sato, said, adding that Greenpeace couldn't confirm if the ship left for the Antarctic Ocean. Kyodo Senpaku, the company that owns the Nisshin Maru, declined comment.
The departure is unusually late. The fleet set sail between Nov. 6 and Nov. 19 in each of the last 10 years until last year.
Greenpeace predicts the duration of research whaling, in which whalers kill the mammals to collect ear wax to check their age and bring their meat home for food, will be shorter this year because of decreasing demand for whale meat.
The fleet normally arrives in the Antarctic Ocean after a voyage of three to four weeks.