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    Variants of the ASPM assessment of the toothfish (Dissostichus eleginoides) resource in the Prince Edward Islands vicinity which attempt to reconcile CPUE and catch-at-length data

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    Numéro du document:
    WG-FSA-SAM-04/12
    Auteur(s):
    Brandão, A., Butterworth, D.S.
    Point(s) de l'ordre du jour
    Résumé

    Two variants of the ASPM assessment of the Prince Edward Islands toothfish resource are examined. One allows for the possibility of changes in somatic growth rate in response to increased food availability as resource abundance drops. The other permits annual fluctuations about a deterministic stock-recruitment relationship. A fit of the first variant yields the biologically implausible result of a decrease in somatic growth rate as abundance drops. For the recruitment variability model, results remain highly sensitive to the relative weights given to CPUE and catch-at-length data in the model fitting processes. Therefore, unfortunately, neither of the variants examined appears able to resolve the discrepancy between the implications of the CPUE and the catch-at-length data regarding the current status of the resource.