Trend in the state of the assessed European commercial fish and shellfish stocks in relation to the Good Environmental Status criteria for fishing mortality and reproductive capacity in the four regional seas

GES = good environmental status; MSY = maximum sustainable yield; F = fishing mortality; FMSY = the fishing mortality that will lead to MSY catches in the long term; SSB = spawning stock biomass (a measure of reproductive capacity); MSY Btrigger = either the biomass at the lower level of the range (5th percentile) of SSB able to produce MSY or Bpa (a stock status reference point above which the stock is considered to have full reproductive capacity, having accounted for estimation uncertainty).

This figure shows trends in the status of assessed commercially exploited fish and shellfish stocks between 1947 and 2018, expressed in two metrics — fishing mortality (F) and reproductive capacity (i.e. spawning stock biomass (SSB)) — relative to their policy thresholds for the Marine Strategy Framework Directive's 'good environmental status' (GES) (i.e. FMSY and MSY Btrigger, respectively). For fishing mortality, a value greater than 1 (F > FMSY) indicates that exploitation exceeds the level that would produce the maximum yield, and is likely to be less sustainable in the long term. For reproductive capacity, the basis of the value of MSY Btrigger differs by stock, either Bpa (a stock status reference point above which the stock is considered to have full reproductive capacity, having accounted for estimation uncertainty) or, for stocks that have been fished at or below FMSY for at least 5 years, the lower bound of SSB when the stock is fished at FMSY (the 5th percentile of the distribution of SSB when fishing at FMSY) if this is larger than Bpa. A value greater than 1 (SSB > MSY Btrigger) means that SSB is either above the lower bound of the SSB when the stock is fished at FMSY or above Bpa. Both indicate that the stocks are in a healthy condition with regard to reproductive capacity.