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    Towards the development of an assessment of stock abundance for Subarea 88.2 SSRUs 88.2C–G – a discussion paper

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    Номер документа:
    S.M. Hanchet and S.J. Parker (New Zealand)
    Представлено (имя):
    Mr Doug Cooper (Секретариат АНТКОМ)

    This paper frames a discussion for improving the assessment of toothfish abundance for SSRUs 88.2C–G. We initially provide a characterisation of the fishery and a summary of available tagging and length frequency data. Although more than 700 tagged fish have been released in this region, only 2 fish have been recaptured. It is likely that the lack of tag recaptures in this region has been caused primarily by the poor spatial overlap of released tagged fish with subsequent fishing effort.

    By drawing on the success of tagging programmes in other CCAMLR fisheries, we develop an approach for improving the spatial overlap of the location of tagged fish and subsequent fishing effort. We identify four main grounds previously fished in SSRUs 88.2C–G. An upper catch limit could be set for each of these grounds based on historic CPUE and a maximum local exploitation rate. It should be noted that the catch limit for SSRUs 88.2C–G will be constrained by the total catch limit for the wider Amundsen Sea stock (SSRUs 88.2C–H) and a subjective decision regarding how it will be split between the 88.2H and 88.2C–G fisheries. We then explore mechanisms for encouraging vessels to complete some or all of their sets within these previously fished grounds. Noting the relatively small number of tags currently available for recapture in this region we further recommend that the tagging rate in this area be increased to 3 tags per tonne in the short term to obtain more precise estimates of abundance and improved data indicative of stock structure.