Consideration of target reference points for WCPO stocks with an emphasis on skipjack tuna

Executive BLOCKINSummary This paper is one of a suite of three pieces of work contracted to inform the WCPFC Management Objectives Workshop, planned to be held prior to WCPFC9. This paper focuses on target reference points, and the other two papers focus on limit reference points and harvest control rules. The presentation of this work to SC8 will provide the feedback necessary to undertake further analysis (as necessary) and refine the material that will be presented to the participants of the WCPFC Management Objectives Workshop. This paper:  discusses biological, socioeconomic and empirical target reference points, their strengths and weaknesses, and decisions needed to operationalise them;  raises issues to be recognised when considering candidate target reference points, including concepts of risk and trade-offs;  provides a simple evaluation of the performance of five alternative target reference points for the WCPO skipjack tuna stock through stochastic projections;  provides a preliminary evaluation of the utility of empirical indicators for this stock. Tables and figures are presented examining the performance of alternative targets relative to:  the risk involved with each target reference point, evaluated relative to candidate limit reference points: 20%SB 0 , 20%SB CurrentF=0 and SB MSY ;  catch levels within the tropical purse seine fishery over the projection period;  the stock biomass vulnerable to the FAD associated purse seine fishery. The paper does not aim to identify which target reference point is 'best' for WCPO skipjack. Target reference points should be defined by managers based on their desired goals for the fishery. In turn, the performance measures to be used when evaluating their performance should be linked to the manager's aims for the fishery, and allow decisions on the 'acceptable' trade-offs between these and other consequences arising from a target reference point. OFP, SPC will be guided by the discussions at SC8 on future work in this area for presentation to the planned WCPFC Management Objectives Workshop. In particular, feedback is sought on:  the planned goals of fishery managers, to help identify new candidate target reference points for evaluation and presentation;  performance measures of interest to managers for evaluation, to allow a fuller analysis of the trade-offs inherent in alternative target reference points, and the timeframe for which they should be calculated;  definition of the limit reference points to be used within evaluations;  alternative empirical indicator reference points for examination.