The report, released by the International Whaling Commission, showed that 128 out of the 333 minke whales caught during the expedition in the Southern Ocean were female, and 122 of them were pregnant, Xinhua news agency reported on Thursday.
Some 114 of the 333 whales caught were not yet adults.
Japan's latest hunting season in the Antarctic Ocean ran from early December to late February, lasting about 12 weeks.
In March 2014, the International Court of Justice ruled against Japan's "research whaling", saying that it served as a front to allow commercial hunting and selling of whales under a scientific exemption.
But the Japanese government continued to claim that the Antarctic program is necessary to study the managing methods of minke populations and that hunting whale is "an ancient part of its culture".
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