Proposals of discussion for the re-evaluation of stock status for the Atlantic shortfin mako

Several issues to be solved in the next stock assessment of Atlantic shortfin mako were raised, especially for the northern stock. It is important to review the past assessment and clarify the problems in advance of the assessment meeting to progress the request by the Commission (re-evaluation of the stock status of Atlantic shortfin mako), on time. Thorough exploration of the stock assessment models, the verification of the output of models, and review of abundance index and major biological parameters to be used for the assessment, are required to improve the assessment. Regarding the stock assessment models, especially for the stock synthesis (SS3), model diagnostics, sensitivity analysis, and future projection are high priorities to complete. Regarding the biological parameter, developments of in-depth explanations to change the productivity (r) and natural mortality (M) are high priorities because the estimate of r in the northern stock in the 2017 assessment was changed to one-half of the amount of the 2012 assessment and M is one of the most influential biological parameters in stock assessment models. Furthermore, we propose a tentative inventory and timeline of these works for the next stock assessment.