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    The random stratified trawl survey to estimate the abundance of Dissostichus eleginoides and Champsocephalus gunnari in the waters of Heard Island (Division 58.5.2) for 2016

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    Document Number:
    WG-FSA-16/23
    Author(s):
    G.B. Nowara, T.D. Lamb and D.C. Welsford
    Submitted By:
    CCAMLR Science Team at AAD (Australia)
    Approved By:
    Dr Dirk Welsford (Australia)
    Abstract

    The annual random stratified trawl survey (RSTS) of 2016 at HIMI was conducted during April, with the completion of 163 stations. The survey was conducted for the second year on the FV Atlas Cove. Sampling protocols such as the design and the duration of the hauls were similar to last year’s survey, but with a new set of randomly selected station points.

    The calculated density of D. eleginoides was half that of 2015 but similar to that of the long-term average for the survey. The C. gunnari density was five times that of 2015 and nearly three times the average. For the managed bycatch species catch rates were lower than the average for macrourids, close to average for C. rhinoceratus and only one-third the average for L. squamifrons. Conversely, the density of aggregated skates was higher than both 2015 and the long term average. The catch of invertebrates in the 2016 survey was two times higher than average, due in part to the greater abundance of jellyfish, which was almost five times higher than average.
    Length measurements were taken for nearly 19,000 fish and biological measurements for more than half of those. Otoliths were collected from 813 D. eleginoides and over 400 toothfish were tagged and released.