Japan's whaling fleet returned Thursday with 333 whales it caught in its first Antarctic harvest since an international court ruling stopped its hunt two years ago.

The Fisheries Agency said that Japanese whalers in the four-ship fleet killed 333 minke whales, filling its catch quota, during the four-month expedition in the Antarctic.

The International Court of Justice in 2014 ruled that Japan's Antarctic whaling program was not scientific as Tokyo had claimed and must stop.

Japan last year conducted only non-lethal research into whaling, but it says killing whales is essential to obtain data on their maturing ages.

Scientific research is exempt from a 1986 international ban on commercial whaling. Opponents of Japan's Antarctic hunt say it's a cover for commercial whaling, since the surplus is sold.

The catch quota under the new research program is about one-third of what Japan used to kill.

Its actual catch has fallen in recent years in part because of declining domestic demand for whale meat. The government has spent large amounts of tax money to sustain the whaling operations.