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    Revised research plan for toothfish in Division 58.4.4b by Shinsei maru No. 3 in 2015/16

    Request Meeting Document
    Document Number:
    Delegation of Japan
    Submitted By:
    Dr Kenji Taki (Japan)

    In this document, we revise stock status assessments of D. eleginoides in research blocks 58.4.4b_1 and 58.4.4b_2 using CPUE analogy method, Petersen method and CASAL model. Detailed results of reanalysis using CASAL models in research block 58.4.4b_1 are described in a separated document.

    We reset the revised research blocs drawn along the outer margin of grids because the previous block had not contained the eastern grids accurately, and recalculated the sea bed area sizes (600-1 800 m) using the same GIS software (GEBCO_08 Grid, version 20100927) as the latest CCAMLR Statistical Bulletin.

    The estimated stock size in block 58.4.4b_1 was 510, 336 and 333 tonnes in CPUE analogy method, Petersen method and CASAL OB_1b model (vulnerable biomass in 2014), respectively.

    The stock sizes of D. eleginoides in block 58.4.4b_2 is estimated at 654 tonnes only by using CPUE method, as the catch and tagging data in block 58.4.4b_2 was not enough to be applied to Petersen method and CASAL models.

    We propose to continue the current research operation for the next fishing season with the same survey design and total sample size of 60 tonnes in order to further strengthen the stock assessments in the area.