Further results for three simple initial Candidate Management Procedures for the toothfish (Dissostichus eleginoides) resource in the Prince Edward Islands vicinity.

• Main Authors: Brandão, Anabela, Butterworth, Doug S
• Format: Report
• Language: English
• Published: Faculty of Science 2019
• Subjects: Butterworth; Tac; Prince Edward Islands
• Online Access: http://hdl.handle.net/11427/30786; https://open.uct.ac.za/bitstream/11427/30786/1/FISHERIES_2019_SEP_SWG-DEM_PTTT_02%20Further%20CMP%20for%20toothfish.pdf

Brandão and Butterworth (2019a) proposed a simple Candidate Management Procedure (CMP) control rule based upon recent trends in CPUE by to provide future TAC recommendations for the Prince Edward Islands toothfish resource. Several suggestions made by a Task Team that evaluated the performance of this CMP are addressed in this paper. In particular, the CMP considered is tuned to target median final depletion levels of 30%, 40% and 50% under OM10 (which is the Operating Model (OM) with a better fit to the last two low trotline CPUE indices). These three CMPs are referred to as CMP30, CMP40 and CMP50 respectively. These CMPs are able to secure an increase in the TAC without adversely affecting the status of the resource under most OMs, especially for the more conservative CMP50. However, the performance under OM17, which addresses the concern with the poor fit to the trotline CPUE data in the last two years by assuming an increased tag loss rate, is not satisfactory. In order to tune these CMPs to react satisfactorily under the scenario assumed by OM17 would heavily penalise TACs under the scenarios reflected by the other OMs. A CMP which incorporates other information, to hopefully be able in some sense to better distinguish what the status of the resource is, might perform better under all OMs. Deterministic projections of mean length and the cumulative number of tags recaptured are examined for this purpose, and are suggestive that incorporation of these data could improve CMP performance.