21st Regular Session of the Scientific Committee

The last stock assessment was conducted in 2022; however, SC18 in 2022 did not achieve a consensus on the management advice for skipjack tuna in the WCPO and provided technical recommendations for future assessments (paragraphs 103-108, SC18 Summary Report). SC19 reviewed Follow-up work on 2022 skipjack assessment recommendations (SC19-SA-WP-07) and provided advice for further improvement (287-293, SC19 Summary Report)

SC21 will review the results of the 2025 skipjack tuna stock assessment, building upon recommendations from SC20 (paragraphs 203 – 206, SC20 Summary Report) and addressing outstanding issues from the 2022 assessment. The review will evaluate improvements in natural mortality and reproductive biology parameters, including new insights into age estimation using otolith analysis and radiocarbon validation, updated fecundity-at-size relationships, and spatial variability in growth. SC21 will also consider the latest CPUE index refinements, including adjustments for preferential sampling, effort creep, and regionally scaled indices, as well as enhancements to tagging data integration, particularly through spatial-temporal modeling and tag-mixing analyses. Emphasis will be placed on evaluating the impacts of effort creep on depletion and recruitment trajectories and on the application of orthogonal polynomial recruitment methods to better capture variability across years, regions, and seasons. 

SC21 will provide scientific advice on model structure, uncertainty characterization, and future stock assessment strategies.