1Marine Fisheries Research and Development Center (JAMARC), Fisheries Research Agency, Yokohama, Kanagawa 220-6115, 2Seikai National Fisheries Research Institute, Fisheries Research Agency, Nagasaki 850-0951, 3National Fisheries Research Institute, Fisheries Research Agency, Yokohama, Kanagawa 236-8648, 4Faculty of Marine Science and Technology, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, Japan.
The catch of red tilefish Branchiostegus japonicus in the East China Sea steeply decreased in the 1990s. Although life history of the red tilefish was studied before the 1970s, the life history traits of the red tilefish will have changed with the decline of population size in the 1990s. We validated the aging method of otolith observation and re-researched the growth and maturation of the fish using monthly samples in 1996-2000. Bertalanffy growth equations of female and male fish were estimated as l(t)=375(1−e−0.317(t+0.420)) and l(t)=520(1−e−0.194(t+0.761)), respectively. Fifty percent maturation sizes in total length were 302 mm and 253 mm for males and females, respectively. The spawning season was from May to December with a peak of September to October, and the main spawning season varied among fishing grounds. Obvious changes in age and growth, spawning period, and maturation characteristics were not detected after the steep decline in the 1990s. Based on the life history traits obtained in this study, fisheries management strategies should be re-examined focusing on the variation in spawning season among fishing grounds.