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EXECUTIVE SUMMARY
The Working Group on Stock Assessment of Small Pelagic Species (WGSASP) benchmark session for the assessment of sardine in the Alboran Sea (geographical subareas [GSAs] 1, 3, and 4) was held at FAO headquarters, Rome, Italy, on 10–14 December 2019. The objective of the meeting was to perform a full analysis and a review of the information and methods used to provide advice on the status of the stock(s), focusing on the considerations of old and new data sources as well as old and new (or improved) assessment models and assumptions. The session was attended by a total of 24 experts, including experts from the region and experts on the species and/or on stock assessment models discussed, as well as an external reviewer (Dr Alexandra Silva).
The session investigated all available input data and carried out an analysis of the performance of six different stock assessment methods: FLR assessment for all (a4a) models, surplus production in continuous time (SPiCT) models, virtual population analysis, length-cohort analysis models using VIT, a length-based spawning potential ratio (LB-SPR) and catch curves. GSAs were treated separately owing to heterogeneity in data availability, and different models were applied to different GSAs according to the data available. Thus, GSA 1 and GSA 3 were assessed using a4a and SPiCT, and validated assessments were produced with a4a; both stocks resulted in overexploitation, and qualitative and quantitative advice was provided, respectively. The stock in GSA 4 was assessed using a combination of data-limited methods (VIT, LB-SPR and catch curves), underlining the extreme influence of assumed life history parameters on stock status. The results were considered preliminary. Quality of advice was commented, uncertainties and model robustness discussed and suggestions for future work listed. The group decided to keep the benchmark open and ongoing in order to assess improvements in data and finalize it within the following year in the presence of an external reviewer
