Three options for rebuilding the cod stock in the eastern Baltic Sea

• Published in: Marine Ecology Progress Series
• Main Authors: Froese, Rainer, Quaas, Martin
• Format: Article in Journal/Newspaper
• Language: English
• Published: Inter Research 2011
• Subjects: Gadus morhua
• Online Access: https://oceanrep.geomar.de/id/eprint/12042/; https://oceanrep.geomar.de/id/eprint/12042/1/BalticCodMEPS.pdf; https://oceanrep.geomar.de/id/eprint/12042/4/m434p197_supp.txt; https://doi.org/10.3354/meps09247

The cod Gadus morhua stock in the eastern Baltic Sea has seen a recent miraculous recovery, mainly due to a drastic decrease in fishing mortality (F). Here we explore 3 options for rebuilding the stock to the size (biomass that can produce the maximum sustainable yield, or Bmsy) that is required by international law and that can support high long-term yields. The first option implements a fishing mortality of F = 0.3, as is aimed for under the current European Commission management plan. The second option implements in addition the current constraint of a maximum annual increase of 15% in total allowable catches until a catch corresponding to F = 0.3 is reached. The third option freezes the 2010 catch for 2 yr before allowing a linear increase with spawning stock biomass towards 90% of the maximum sustainable yield. We show that the first option provides the highest catches for the first 3 yr, but fails to rebuild the biomass to the level of Bmsy. The second option rebuilds the biomass above Bmsy only temporarily and results in the lowest catches over a 10 yr period. The third option rebuilds the biomass above Bmsy and provides high catches and the highest profit within 10 yr. Within a decade, all 3 options provide several-fold higher biomasses, catches, and profits compared to the current situation, underlining the benefits that can be obtained from proper fisheries management. In comparison, the so-called precautionary management approach (F = 0.6) implemented until 2006 would perform worse in every respect.