22nd Regular Session of the Scientific Committee

SC22 will review SEAPODYM activities since its 2019 review to assess progress in addressing SC21 and 2019 review recommendations, evaluate the robustness and transparency of the modelling framework, and provide guidance on remaining gaps, priority areas for further work, and the appropriate role of SEAPODYM within WCPFC scientific processes, including its use in stock assessment and scientific advice.

• Updates on progress since the 2019 SEAPODYM Review will be presented through two papers covering methodological developments and applications to Pacific tuna species. The work will focus on actions taken in response to key recommendations from the 2019 review and SC21, including further validation of SEAPODYM through comparisons with alternative modelling approaches and, where relevant, testing with simulated data. The methodological paper is expected to report on improvements in model structure, estimation procedures, and diagnostics, including convergence diagnostics, sensitivity analyses for key parameters and assumptions, likelihood profiles, and evaluation of model behaviour under different data inputs and optimisation periods. It will also address the characterisation of uncertainty in model estimates. The applications paper is expected to demonstrate how SEAPODYM performs when applied to Pacific tuna stocks, including evaluation of population dynamics, spatial structure, and variability, and how model outputs compare with other assessment approaches.