General Fisheries Commission for the Mediterranean - GFCM

Report on the SGSABS benchmark session for Black Sea anchovy in geographical subarea 29

Tue, Jul, 2023, 1am - Thu, Jul, 2023, 1am

Download the report (available only in English): PDF


The benchmark session for the Black Sea anchovy (Engraulis encrasicolus ponticus) of the Subregional Group on Stock Assessment in the Black Sea (SGSABS) was held from 4 to 6 July 2023 in hybrid modality in Burgas, Bulgaria. The objective of the meeting was to perform a full analysis and review of the available information and methods used to provide advice on the status of the Black Sea anchovy. A particular focus was placed on the considerations of data sources needed to perform the assessment with the age-structured model SAM, which has been tried in previous meetings, and Surplus production models, particularly SPiCT. The session was attended by a total of 16 experts, including experts from the region and experts on stock assessment from the GFCM. An external reviewer (Patricia Gonçalves), a representative of the European Commission DG MARE (Mario Sbrana) and the BlackSea4Fish project team were also attending the meeting. The detailed exploration of all available data on biology and fisheries, as well as the results and diagnostics from the two models (SAM and SPiCT), indicated that the results of the assessment performed by SAM were jeopardized by poor cohort consistency, weak retrospective analysis and misunderstanding of fishery selectivity. Accordingly, the SPiCT model was used to provide quantitative advice, since thisassessment results and diagnostics met the criteria to accept the assessment. However, the group stressed the urgency of re-evaluating the existing historic otoliths and estimating at least one standard set of von Bertalanffy growth parameters and age-length keys representing the period dominated by the fast-growing anchovy before exploring the age-structured model again. 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.