A Japanese fleet comprising five ships returned to port on Friday morning after killing 333 minke whales as part of what it has called “scientific research”. The fleet had flouted a global moratorium when it set sail for the Southern Ocean last November. Japan’s Fisheries Agency said three ships returned on Friday morning.

Japan has made use of a loophole in International Whaling Commission rules that allows only scientific whaling. The Fisheries Agency’s press release called the mission “research for the purpose of studying the ecological system in the Antarctic Sea”. It said its research was focused on the reproductive and nutritional cycles of minke whales. “Since a majority of both the males and females taken were mature, this indicates that the species is reproducing healthily,” Reuters reported the agency as saying.

In 2014, the International Court of Justice had ruled that the country must end all Antarctic whaling. The international moratorium on whaling has been in place since 1984.

Japan, however, appears intent to continue the practice, on the premise that it is conducting research towards its ultimate goal of resuming commercial whaling. The country has maintained for decades that the animal is not endangered and that eating whale is part of Japanese culture. According to Reuters, even though whale meat is still sold in Japan, much of it is no longer consumed.

Japan intends to cull 4,000 more whales over the next 12 years as part of its “research”.