The International Whaling Commission opened its annual meeting Thursday in Shimonoseki, Yamaguchi Prefecture, with a fierce tug-of-war expected over Japan's plan to expand its "research whaling" and seek resumption of commercial whaling.

The 54th meeting of the 42-member IWC began in the Kaikyo Messe Shimonoseki convention center with a closed-door Science Committee session focusing on science and data.

But stormy debate is expected as Japan aims first to win the committee's support of its research-whaling program, including a new plan to catch sei whales, which the IWC wants protected, in the Northwest Pacific.

The key issue will be how scientists from the 42 member countries assess Japan's claim that there are 28,000 sei whales in the waters, outnumbering the estimated 25,000 minke whales, said Seiji Osumi, director general of Japan's Institute of Cetacean Research.