TOKYO-Japan on Wednesday kicked off a whaling campaign in the northwestern Pacific, in a move sure to anger animal rights activists and others calling for an end to the hunts.

Three ships are leaving port on a three-month mission to catch 43 minke whales and 134 sei whales, according to the government.

The new mission comes after Japan on Sunday started an annual coastal whaling hunt along its northern Pacific shores, aiming to catch 47 minke whales until mid-July.

Japan is a signatory to the International Whaling Commission’s moratorium on whale hunting, but uses a loophole in the temporary ban allowing for lethal scientific research.

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.

Foreign pressure on Japan to stop whaling has hardened conservatives and politicians, making it a rare thorny issue for Japan’s otherwise amiable diplomacy. Japanese consumer demand for whale meat has declined significantly over the years, however, throwing a question domestically over whether whaling missions still make economic sense.

In 2014, the United Nations’ International Court of Justice (ICJ) ordered Tokyo to end its 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.

The Antarctic hunt has seen high seas clashes between Japanese whalers and animal activists.