The 8,725 ton Hiyo Maru (飛鷹丸) was the largest member of the Japanese whaling fleet; providing fuel, resources, and stock storage space for that fleet and its crew.

According to Greenpeace, after a dispute with the Panamanian Government in 2008, it was de-flagged and re-registered to Japan.

[4] The Hiyo Maru served as the fuel tanker for Japan's whaling fleet,[5] and was alleged by Greenpeace to also transport whale meat.

During the 2007-2008 whaling season in the Southern Ocean, Greenpeace tried to stop a fuel transfer between the Oriental Bluebird and the Nisshin Maru by positioning a zodiac boat between the two ships.

Hours after the incident, the Sea Shepherd vessel the Farley Mowat rammed the Oriental Bluebird and tore a six-inch (150 mm) gash into the ship's hull.