Stock Assessment and ABC Calculation for Japanese Sardine (Sardinops Melanostictus) in the Northwestern Pacific under Japanese TAC System

抄録

　Stock assessment for the Japanese sardine (Sardinops melanostictus) in the northwestern Pacific was conducted based on VPA and biomass surveys independent from commercial fisheries data. The stock size of Japanese sardines in the northwestern Pacific has shown a continuous decrease from 1987 to 2003 and the stock biomass estimate for 2003 was about 130 thousand tons. The spawning success (RPS: number of recruits/spawning biomass) has been 22 inds./kg in average and fluctuated between 5 and 61 inds./kg during the recent 10 years. From the historical perspective, the current stock status would not be in the conditions for rapid stock recovery. The acceptable biological catch (ABC), that is the biological criterion for the TAC, is set to rebuild the spawning biomass at least to the level at which the recruits are expected to be comparable with those of 1996 year-class. Some hypothetical scenarios for controlling the catch amount were explored, in order to avoid intensive fishing efforts on dominant recruits.