Japan said Tuesday it killed 177 whales off its northeast coast in an annual hunt that sparks anger among animal rights activists and others.
Three ships which left port in June returned with 43 minke whales and 134 sei whales, the number stipulated beforehand, according to the country's fisheries agency.
Japan is a signatory to the International Whaling Commission's (IWC) moratorium on hunting, but exploits a loophole which allows whales to be killed in the name of scientific research.
The studies are "necessary to estimate the precise number of (sustainable) catches as we look to restart commercial whaling", agency official Kohei Ito told AFP.
Norway -- which does not consider itself bound by the 1986 moratorium -- and Iceland are the only countries in the world that authorise commercial whaling.
Tokyo claims it is trying to prove the whale population is large enough to sustain a return to commercial hunting for a traditional source of food.
But Japanese consumer demand for whale meat has declined significantly over the years, raising the question of whether such hunts still make economic sense.
Foreign pressure on Japan to stop whaling has only made conservatives and politicians more resolute about continuing. It is a rare thorny issue in Tokyo's otherwise amiable diplomacy.
In 2014 the United Nations' International Court of Justice (ICJ) ordered Tokyo to end a regular hunt in the Antarctic waters, saying the project did not meet conventional scientific standards.
Japan cancelled its 2014-15 hunt, only to resume it the following year under a new programme -- saying the fresh plan is genuinely scientific.
Its hunt in the Antarctic has seen clashes on the high seas between Japanese whalers and animal rights activists.