Japan's whaling fleet was scheduled to leave port shortly for the South Pacific with orders to kill up to 50 humpback whales, the first known large-scale hunt of humpback whales harpooned since a 1963 moratorium put them under international protection. The Fisheries Agency has refused to release the fleet's departure date. But the lead whaling ship's operator, Kyodo Senpaku Ltd., said they could set sail from the southern city of Shimonoseki this weekend. The ships, led by the 8,030-ton Nisshin Maru, will embark on their largest-ever scientific hunt in the South Pacific. Besides humpbacks, they will take up to 935 Antarctic minke whales and up to 50 fin whales. Humpback whales have been off-limits since 1963 except for a small number caught under a subsistence whaling program by the semiautonomous Danish territory of Greenland and the Caribbean nation of Saint Vincent and the Grenadines. Last year, they caught one humpback each, according to the International Whaling Commission.