Japan resumed commercial whaling for the first time in 31 years, and a fleet of vessels began catching its first whales on Monday.
Fleets that left from the city of Kushiro in Hokkaido, and from the port in Shimonoseki, Yamaguchi prefecture, were celebrated at local ceremonies after Japan withdrew from the International Whaling Commission, the Asahi Shimbun reported.
One of the species the Japanese ships are aiming to hunt, the Sei whale, is on the endangered species list.
"This is a sad day for whale protection globally," said Nicola Beynon of Humane Society International, according to the BBC.
Japan has begun a "new and shocking era of pirate whaling," Beynon added.
The mood may have been festive at Japanese ports, however.
Shimonoseki's mayor, Shintaro Maeda, expressed enthusiasm about the whaling expedition.
"I am proud and joyful the ceremony for the ships that are resuming commercial whaling after 30 years is being held in Shimonoseki," Maeda said.
Japan's agriculture minister Takamori Yoshikawa defended whale consumption at the same ceremony.
"Many people [in Japan] eat whale, and hope the whaling industry is permanent," Yoshikawa said, according to the Asahi.
The ships have a permit to catch 227 whales.
Whaling has adverse effects on the world's ecosystem. According to marine scientists, whales are critical to the food chain, stabilizing food flow and maintaining a healthy ocean.
Japan last hunted whales commercially in 1986. Despite its compliance with the International Whaling Commission for more than three decades, Japan used an exemption to the ban to allow the killing of anywhere from 200 to 1,200 whales annually, citing "scientific research."
According to U.S. nonprofit Whale and Dolphin Conservation, whales are highly intelligent mammals that are sociable and exhibit high levels of cooperation, intelligence and social learning.