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    Descriptive analysis of the toothfish (Dissostichus spp.) tagging programme in Subareas 88.1 & 88.2 for the years 2000–01 to 2010–11

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

    Descriptive analyses of the toothfish tagging programme in Subareas 88.1 and 88.2 are updated, including summaries of data for the 2011 season. Overall, a total of 28 458 Antarctic toothfish have been reported as released and 1417 recaptured, and 1124 Patagonian toothfish released and 67 recaptured since 2001. In recent years, most vessels have achieved or exceeded the target tagging rate of one toothfish per tonne of catch in the Ross Sea region.

    Tag recapture data showed that most fish are recorded as being recaptured only a short distance from their point of release, typically less than 100 km. However, several long distance movements of tagged Antarctic toothfish between the north and slope regions have been observed. Long distance movements to the north were recorded for six fish that moved from SSRU 88.1H to 88.1C; two moved from SSRU 88.1H to 88.1B; and one from SSRU 88.1I to SSRU 88.1C. Long distance southwards movements were recorded for three fish that moved from SSRU 88.1B to SSRUs 88.1H; and one to SSRU 88.1I. In addition, several fish moved long distances on the slope and the shelf, with movements between SSRUs 88.1H, 88.1I, and 88.1K to grounds off Terra Nova Bay and Ross Island in SSRU 88.1J and vice versa..

    The total number of recaptures in 2010 and 2011 was at a similar level to 2007 and 2008 and about double that in 2009. The reason for the low number of recaptures in 2009 is unclear but is more likely to be related to the different locations of fishing in 2009 rather than a lower detection rate.