Recommendation to TWG CMSA07 on a stock assessment model platform based on work completed as part of the TWG CMSA assessment modeling project

The TWG CMSA has been tasked to complete the stock assessment of chub mackerel as soon as possible in accordance with the terms of reference agreed at the TWG CMSA meeting in December 2017, even if such assessment is provisional, and provide advice and recommendations to the Commission (CMM for Chub Mackerel). An analysis of uncertainty has therefore been conducted by the Working Group following methods of Deroba et al (1995) to test the robustness of four stock assessment models to error via simulation, the results of which could help develop guidelines for the selection for a stock assessment model. Details of the ranking of performance measure and choice of summary metrics were developed through intersessional work conducted since the TWG CMSA06 meeting in September 2022 (See NPFC-2023-TWG CMSA07-WP01) Based on the comparison, with respect to the models investigated in this project (ASAP, KAFKA, SAM, VPA), the SAM should be the recommended model for stock assessment of chub mackerel.