Japan plans to double its whale catch in the northwest Pacific Ocean and add sei whales to the list, a government official said, rebuffing international criticism of the country's whaling program. A total of 50 sei whales will be caught during the June-October season as part of Japan's research of whale feeding habits, migrations and life cycles, said Takanori Ohashi, an official with Japan's Fisheries Agency. Under the research program, Japan will hunt 150 minkes, 50 Bryde's and 10 sperm whales in the northwest Pacific as well as the sei whales. Sei whales grow as long as 85 feet. The hunt is permitted by the IWC*, but opponents say Japan's research is commercial whaling in disguise. Whale meat is often sold later in Japanese restaurants. Based on visual research conducted since 1994 by the Japan's Fisheries Agency, the Japanese government estimates there are around 100,000 sei whales in waters around the world, including about 28,000 in the northwest Pacific.