With another boat to join the operation in June, a total of five boats are expected to catch 120 minke whales in waters off the Sanriku Coast and Hokkaido by late October, according to the Fisheries Agency.
Two boats left Ishinomaki, Miyagi Prefecture, early in the morning, before being joined by two other vessels that departed from Hachinohe in Aomori Prefecture. The fifth boat will leave from Abashiri, Hokkaido.
"We would like to provide fresh and delicious whales for everyone who is waiting," said Nobuyuki Ito, president of a whaling company in Ishinomaki.
Ito's company is planning to catch whales in the coastal waters of Aomori, Iwate and Miyagi prefectures until early June before heading north to the coastal waters off Hokkaido.
The two vessels that left Hachinohe are operated by companies in Minamiboso, Chiba Prefecture, and Taiji, Wakayama Prefecture.
Commercial whaling in offshore waters is also scheduled to start around June, according to the agency.
Japan resumed hunting whales for commercial purposes on July 1, 2019, a day after formally leaving the International Whaling Commission.
As an IWC member, Japan had halted commercial whaling in 1988 but continued catching whales for what it called research purposes, a practice criticized internationally as a cover for commercial whaling.