General Fisheries Commission for the Mediterranean - GFCM

Benchmark sessions for the assessment of blackspot seabream in GSAs 1–3

Thu, May, 2020, 1am - Thu, May, 2020, 1am


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The Working Group on Stock Assessment of Demersal Species (WGSAD) benchmark session for the assessment of blackspot seabream (Pagellus bogaraveo) in geographical subareas (GSAs) 1 and 3 was held in different sessions over a two years period. The first session was held back-to-back to the third meeting of the Subregional Committee for the Western Mediterranean (Sète, April 2019), the second was held in parallel with the WGSAD (FAO headquarters, Rome, December 2019), and the third one was held online with successive sessions carried out between March and May 2020. It was attended by three experts from Morocco, three experts from Spain, two external reviewers and technical staff from the regional projects of the Food and Agriculture Organization of the United Nations (FAO) and the Secretariat of the General Fisheries Commission for the Mediterranean (GFCM). The sessions addressed various aspects of the assessment of blackspot seabream in the Strait of Gibraltar area, with a focus on issues related to the input data and assumptions, in particular on biological parameters including growth, mortality, length-weight relationship and maturity, and issues related to the suitability of assessment models. The benchmark assessment was produced for the reference year 2018, at the last session of 28 May 2020, by means of the GADGET model which was progressively adapted to this very particular fishery. In previous assessments of blackspot seabream within the framework of the WGSAD, five different methods had been used: three length-based (VIT, LCA, LBB) and two surplus production type methods (BioDyn and SpICT). All of them produced compatible results with those obtained in the last attempt with GADGET, which is a statistical model, thus providing more robustness to the estimated reference points.