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    Progress in the evaluation of management strategies for the Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea region

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    Document Number:
    WG-SAM-15/48
    Author(s):
    S. Mormede, A. Dunn, S.J. Parker and S.M. Hanchet (New Zealand)
    Submitted By:
    Dr Rohan Currey (New Zealand)
    Abstract

    Management Strategy Evaluation (MSE) has been acknowledged as the best practice to take account of uncertainties in the assessment of stocks and as a method to ensure robust management approaches. The Scientific Committee of CCAMLR has recommended MSE be used to determine the extent to which the management objectives for toothfish fisheries are being met. While the choice of management targets used by CCAMLR has been based on MSE simulations, formal MSE studies have yet to be fully implemented.

    To date there have been a number of analyses and simulation studies reported for the assessment of toothfish that have evaluated the sensitivity of models and the resulting estimates of sustainable yields with respect to management objectives.

    In this paper we develop approaches using operating and estimation models and show how they can be used to assist in identifying aspects of model and parameter misspecification that could then be evaluated using more computationally complex MSE approaches. We apply this to the assessment of Antarctic toothfish in the Ross Sea region with some example parameters and parameter values.

    Our results can assist in prioritising further MSE analyses that fully account for the feedback mechanisms that the CCAMLRs decision rules provide. However, we note that different assessment models may be sensitive to different parameters and parameter values, and may require different approaches to MSE. We also note the importance of developing and maintaining data collections that can contribute to more accurate parameter specifications for any parameters identified as priorities through the MSE process.