Changes of group construction accompanying with growth and maturity in blue-barred parrotfish (Scarus ghobban), and influences of the fishing targeting the immature group to the stock

The fishery at the studied area has mostly targeted the all female group to be about 85% of total numbers; thus, the fishing pressure to mature females was revealed to be very small. However, the VPA highlighted that the most individuals up to 3 years of age belonging to the all female group died either by fishing or naturally. Thus, a few individuals attained sexual maturity in each cohort. Extremely high fishing pressure against the mature age groups shortly added during the study period, thereafter spawning stock biomass (SSB) and %SPR rapidly decreased, the latter to the level of about 20%, beyonding the biological reference point. Cohort sizes during the years 1994-2012 have fluctuated in magnitude twice, and those of latter half period, coincide to both SSB and %SPR decreases, were smaller than those of earlier half but were stable without any trend of decreases.