Bull. Jpn. Soc. Fish. Oceanogr. 71(2), Page 122-130, 2007   Estimation of annual bluefin tuna catch in weight by the troll fishery in Nagasaki Prefecture, based on the Japanese official fisheries statistics Harumi Yamada1†, Ken’ichi Yamamoto2 and Akira Nitta3 1 National Research Institute of Far Seas Fisheries, 5-7-1, Orido, Shimizu-ku, Shizuoka, Shizuoka 424-8633, Japan 2 Nagasaki Prefectural Institute of Fisheries, Taira, Nagasaki, Nagasaki 851-2213, Japan 3