Ecological risk assessments for the effects of fishing: A comparison and validation of PSA and SAFE
Zhou, S and Hobday, AJ and Dichmont, CM and Smith, ADM, Ecological risk assessments for the effects of fishing: A comparison and validation of PSA and SAFE, Fisheries Research, 183 pp. 518-529. ISSN 0165-7836 (2017) [Refereed Article]
Two tools to assess impacts of fisheries on fish species have been developed for use as part of the Ecological Risk Assessment for the Effects of Fishing (ERAEF) toolbox, namely, the Productivity and Susceptibility Analysis (PSA) and the Sustainability Assessment for Fishing Effect (SAFE). Both have been applied to major Australian Commonwealth fisheries and, with various modifications, adopted internationally. However, there has been no formal comparison between the two approaches and no validation against other data-rich assessment methods. Here, we conduct three comparisons: between PSA and SAFE, between PSA, SAFE and Fishery Status Reports (FSR), and between PSA, SAFE and data-rich quantitative stock assessments. PSA and SAFE use similar data. However, PSA typically downgrades quantitative information into an ordinal scale between 1 and 3, whereas SAFE uses the quantitative information as continuous numerical variables in equations at each assessment step. As intended in its original design, PSA is more precautionary toward protecting species, classifying many more species at medium or high risk than SAFE. A comparison with FSR for overfishing classification shows an overall misclassification rate of 27% (26 stocks) by PSA (overestimating risk in all these cases) and 8% (59 stocks) by SAFE (overestimating risk in 3% and underestimating risk in 5% of cases). A comparison with Tier 1 stock assessments (18 stocks) shows an overall misclassification rate of 50% by PSA and 11% by SAFE (all overestimating risk). These comparisons show that the performance of these two ERA tools may deliver the expected benefits in terms of prioritizing high risk species, but, in the case of PSA, the screening may be too precautionary. Validation with more quantitative methods is an important step to guide the further improvement of these important tools.
data-poor, bycatch, risk assessment, ecosystem approach to fishing