Report of the 2019 shortfin mako shark stock assessment update meeting

ICCAT (2020) Report of the 2019 shortfin mako shark stock assessment update meeting. ICCAT Collect Vol Sci Papers 76:1–77

Shark Species Group update the projections of future stock status for shortfin mako shark based on the 2017 stock assessment during the 2019 intersessional meeting. The Group combined the Stock Synthesis MCMC projection results, which showed that although there is large uncertainty in the future productivity assumption for this stock, there is a long lag time between when management measures are implemented and when stock size starts to rebuild. The probability of success of several of the measures contemplated in ICCAT Rec. 17-08 were also reviewed through additional projections. Specifically, alternative TAC, size limit, and live release measures were explored with two tools: Stock Synthesis and the Decision Support Tool. In addition, the Group continued to review the effectiveness of potential mitigation measures to reduce by-catch and mortality of shortfin mako in ICCAT tuna fisheries. Finally, reviewed the activities and progress of the SRDCP, including habitat use based on electronic tagging; post-release mortality; genetic analysis of shortfin mako; movements, stock boundaries and habitat use of silky sharks and other species; movements and habitat use of porbeagle; and the 2020 workplan.