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    Research plan for the 2015/16 exploratory longline fishery of Dissostichus spp. in Division 58.4.1

    Request Meeting Document
    Document Number:
    Delegation of Japan
    Submitted By:
    Ms Chika Fukugama (Japan)

    The current season (2014/15) is the final one of the first three-season research which began in 2013 in data-poor fisheries. In the present report, catch, effort and biological data recorded by all effective vessels were analyzed for the improvement of stock assessment in the research blocks. Based on the result, the next three-season (2016-18) research plan in Division 58.4.1 is also presented.

    The stock sizes for five research blocks (58.4.1_1, 58.4.1_2, 58.4.1_3, 58.4.1_4 and 58.4.1_5) were estimated by the Petersen estimator and the CPUE x seabed analogy method using updated CCAMLR C2 data and reference area sizes.

    Although no toothfish fishery data along the shelf area in austral autumn – winter was available, SSRU 58.4.1 C may be also one of the important spawning grounds for D. mawsoni from the degrees in development of GSI in summer comparable with those in the north of Subarea 48.6 and Banzare Bank.

    Understanding of the resource structure through clarification of their life history is essential to establish stock assessment and robust stock/ fisheries management of Dissostichus spp. population(s) in data- poor exploratory fisheries. During the second three-season research, we will continue enhanced tagging program, and collection and analysis of biological data including otoliths and gonads to clarify migration route and associated life stages of the fish.

    To this end, we propose to follow the current research style in the current research blocks for the second three-season research with the sample sizes estimated following the procedure recommended at the WG-FSA in 2013 in order to maximize the expectation of tag-recapture to the extent possible under the precautionary exploitation rate.