Fisheries science is geared to two parameters: the fishing mortality rate (F) and spawning biomass. If fishery is to be sustainable, F should be sufficiently low, and the spawning mass sufficiently large. Experience has shown that functioning fisheries management systems need limit reference points and target reference points. An adequately low F_Target should achieve a low mortality rate. An additional limit reference point (F_MSY) should prevent the fishing mortality rate from ever rising to critical levels, indicating that catches are too high. In future the F_MSY should replace the conventional F_PA-value. In practice these F-values are extremely important points of reference for the fisheries. In terms of total biomass, however, only a target reference point, the B_MSY, is specified. B_LIM is the crucial lower threshold for spawning stock which should never be reached. In this event the stock would be overfished.

Fig. 5.4 > © maribus