Rebuttal to Froese and Proelss "Evaluation and legal assessment of certified seafood"

In a recent paper, Froese and Proelss [1] contend that 31% of stocks targeted by Marine Stewardship Council(MSC) certified fisheries are overfished and subject to ongoing overfishing and a further 8% are either overfished or subject to overfishing. Their results are derived using a definition of "overfished" that is not consistent with internationally accepted definitions and interpretations. In addition, the authors used unrealistic estimates of biomass that produce Maximum Sustainable Yields(BMSY) obtained through methods that are inconsistent with the approach used by the management agencies and scientific advisory bodies responsible for the stocks inquestion. Analyses such as that published by Froese and Proelss are an important part of the external, independent scrutiny of the programme that MSC welcomes. However there are a number of serious flaws in their analysis, data and resulting conclusions that this response seeks to correct. Using data for 45 stocks exploited by MSC certified fisheries(>60% of total fisheries in the programme and >80% of total certified catch), internationally accepted methods for determining MSY reference points, and internationally accepted definitions of the terms "overfished" and "overfishing", no stocks exploited by MSC certified fisheries can be defined as overfished (below their limit reference points).