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 FTarget should achieve a low mortality rate. An additional limit reference point (FMSY) should prevent the fishing mortality rate from ever rising to critical levels, indicating that catches are too high. In future the FMSY should replace the conventional FPA-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 BMSY, is specified. BLIM 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