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Further refinements of the BR CMP

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posted on 19.10.2021, 12:57 authored by Doug ButterworthDoug Butterworth, Rebecca A Rademeyer
This paper seeks improved performance of CMP BR_6 (Butterworth and Rademeyer 2021) to avoid possible very low TACs for the East area. This can be improved somewhat by placing caps on the East area TAC for the next 10 years, with an upper cap of 36 000 mt (equal to the current TAC for this area) suggested. A further modification indicated for BR_6 is lessening the maximum downward TAC change possible from 50% to 30%, which does not increase resource risk markedly. Stochastic results for the resultant BR10 CMP show a few instances of extirpation of the eastern stock for R2 OMs, indicating a possible need for further refinement of this CMP. Given strong differences in especially east stock trajectory projections for the different recruitment (R) scenarios, presenting CMP results separately for each R scenario is suggested, rather than some weighted average across the three, to provide a more informative basis to compare performances across CMPs. Appendices provide mathematical specifications of the BR CMP and indications for sensitivity of BR10 performance statistics to tuning to weighted rather than unweighted OMs.

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Department of Mathematics and Applied Mathematics, University of Cape Town