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    A characterisation of the toothfish fishery in Subareas 88.1 and 88.2 from 1997–98 to 2010–11

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    M.L. Stevenson, S.M. Hanchet, S. Mormede and A. Dunn (New Zealand)

    The exploratory fishery for Dissostichus spp. has now been operating for fifteen years in Subarea 88.1 and for ten years in Subarea 88.2. This report summarises the timing, depth, and location of fishing together with the catch of Dissostichus spp. and bycatch species by year for the period 1997–98 to 2010–11. During the 2010–11 fishing year most of the catch in Subarea 88.1 came from the slope SSRUs 88.1H and 88.1I, and SSRU 88.1K. About 63% of the catch limit in the north was taken from 88.1C with the rest taken from SSRU 88.1B. The catch limit from the shelf was taken mainly from 881J. Most catch from Subarea 88.2 was taken from SSRU 88.2E but over 100 t was taken from each of SSRU 88.2D and 88.2F, and SSRU 88.2C was fished for the first time.

    Unstandardised raw catch and effort data examined during this study suggest that the median toothfish catch per set has generally increased over the course of the fishery whilst the median number of hooks per set has remained relatively constant. Other indicators of CPUE including unstandardised catch per set and catch per hook have varied considerably over time in each of the fisheries showing no trend. There is no evidence of any truncation of the overall length frequency distribution, but some evidence for a reduction in median fish length in SSRUs 88.1H and 88.1I over the last 1–2 years as a mode of smaller (c. 100 cm) fish is selected by teh fishery, most likely  related to fishing depth. We conclude that from data examined from the fishery to date there is no evidence for substantial changes in population structure or abundance at the regional (Subarea) or local (SSRU) level.