A characterisation of the toothfish fishery in Subareas 88.1 and 88.2 from 1997/98 to 2009/10

The exploratory fishery for Dissostichus spp. Has now been operating for 14 years in Subarea 88.1 and for 9 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 2009–10. During the 2009–10 fishing year most of the catch in Subarea 88.1 came from the slope SSRUs 881H and 881I, with a reduced catch from 881K due to ice conditions. The catch limit in the north was all taken from 881C, whilst the catch limit from the shelf was taken mainly from 881J. Most catch from Subarea 88.2 was taken from SSRU 882E, with little fishing occurring in the other SSRUs, and the catch limit was under caught by 250 t. Unstandardised catch per set and catch per hook have varied considerably over time in each of the fisheries showing no trend in the main fisheries in Subarea 88.1 and SSRU 88.2E, but a slight decline in SSRU 882CDFG over the last two years. We carried out a more detailed characterisation of Patagonian toothfish catches for the first time. A total of 124 t of Patagonian toothfish has been reported from the fishery, with catches mainly coming from the northwest of the Ross Sea region (SSRUs 881A and 881B). Some observers appear to have problems distinguishing the two toothfish species, and many small (<100 cm TL) toothfish which have been reported as Antarctic toothfish should in fact be Patagonian toothfish. We recommend that observers be made aware of this issue, and that the species identification be independently checked through examination of a subsample of otoliths from these small fish. A major source of uncertainty in the current stock assessment concerns the recruitment dynamics. It has been suggested that a pre-recruit longline survey be developed to collect data to better estimate these parameters. We recommend WG-FSA consider whether such a survey would be worthwhile and identify several fishing grounds on the Ross Sea shelf where such a survey could be carried out.