Five Japanese whaling ships set off Monday to begin the first commercial whale hunt in more than 30 years.

Japan stopped commercial whaling in 1988 after the International Whaling Commission (IWC) imposed a moratorium on killing the giant mammals.

But despite the global ban, Japan continued to hunt whales for what it claimed was scientific research. Critics have long disputed that claim, calling it commercial whaling in disguise.

In the 2017-2018 whaling season, Japanese sailors killed 333 minke whales in Antarctic waters. More than 120 were pregnant females.

In December, Japan announced it was leaving the IWC June 30.

The whaling fleet sailed from the port of Kushiro, on the northern island of Hokkaido. They will hunt minke, sei and Bryde’s whales in Japanese waters.

Japan’s return to commercial whaling has created an international outcry.

“Japan leaving the IWC and defying international law to pursue its commercial whaling ambitions is renegade, retrograde and myopic,” said Kitty Block, president of Humane Society International. “It is undermining its international reputation for an industry whose days are so clearly numbered, to produce a product for which demand has plummeted.”

But some experts say Japan’s move might be a blessing in disguise for some whales, because it will mean that Japan will stop hunting whales in the Southern Ocean, the Atlantic and other sensitive locations.

Japan’s Fisheries Agency set a quota at 227 whales for this year.

