Results for a potential Candidate Management Procedure for the Toothfish (Dissostichus eleginoides) Resource in the Prince Edward Islands vicinity
Brandão and Butterworth (2019a) investigated various target-based Candidate Management Procedures (CMPs); however, their performances under operating models OM17 and OM18 were not satisfactory so that further investigation/adjustment of these CMPs was needed. An adjusted form of CMP(mean+tag) of Brandão and Butterworth (2019a), which incorporates trends in the cumulative number of recaptured tags as well as the recent mean of the trotline CPUE, is considered in this paper. This CMP seems to perform satisfactorily under most of the OMs, in that median catches increase for most of the projection period while catch rates keep increasing and the median final depletion remains above the specified target value under OM10. However, the performance of the CMP under OM17 is still not satisfactory. It might be that it will not be possible to improve the performance of the CMP under OM17 without decreasing TACs under other scenarios for which the status of the resource does not necessitate lower catches. However, as this OM assumes quite an extreme tag loss, perhaps less weight should be accorded to the performance of the CMP under this scenario, even perhaps considering it as a robustness test rather than part of this Reference Set.