Scalefish Purple Wrasse Catch MSY

Catch-MSY Results

Catch-MSY results based on the assumption of “medium” resilience suggest that Purple Wrasse biomass is depleting (Figure 1). However, this apparent trend is likely to be driven fishery changes rather than abundance, including a known substantial decline in fish trap use after 2006/07 and the recent lack of restaurant demand for live fish during the start of the COVID pandemic. Median estimates of biomass depletion peaked at 30% of unfished levels in 2012/13 (lower 90% CI = 20%) with depletion at 32% of unfished levels in the 2019/20 (lower 90% CI = 10%) (Figure 1).

Figure 1: Trends in estimated biomass depletion (biomass divided by unfished biomass) and associated confidence intervals (CIs). The dotted red line marks a common target reference point, which is the biomass assumed to deliver the maximum sustainable yield (Btarget). The continuous red line marks a limit reference point (Blimit).
Figure 2: Trends in harvest rate and associated confidence intervals (CIs) relative to the estimated target fishery mortality (Ftarget).
Figure 3: Trends in catch relative to the estimated maximum sustainable yield (MSY) and associated confidence intervals (CIs).