Simple target-based CMPs for southern bluefin tuna
reportposted on 12.03.2021, 08:21 by Doug Butterworth, Melissa Jacobs, Rebecca A Rademeyer, Mitsuyo Miyagawa
Simple target-type CMPs for SBT, first developed in 2018, and using CPUE, close kin mark recapture (CKMR) and gene tagging (GT) information, are further refined and tuned to median recovery of 30% and 35% of the pristine TRO in 2035 and 2040 respectively for the operating models as finalized for 2019. These tunings are carried out for each information type separately, and then selections are made amongst differently weighted combinations of the resultant three CMPs. Particular stress is placed on attempting to achieve greater values for the lower percentile for SSB depletion in the tuning year, especially for the robustness test involving low recruitment, which is best achieved by the GT index-based CMP. For that reason, the preferred combined CMP gives 60% weight to the GT-based CMP, with 20% to each of the other two.