Skip to main content

    The annual random stratified trawl survey in the waters of Heard Island (Division 58.5.2) to estimate the abundance of Dissostichus eleginoides and Champsocephalus gunnari for 2015

    Request Meeting Document
    Document Number:
    G.B. Nowara, T.D. Lamb and D.C. Welsford (Australia)
    Submitted By:
    Dr Dirk Welsford (Australia)

    The annual random stratified trawl survey (RSTS) at HIMI was conducted during May of 2015, with the completion of 163 stations, an additional five stations compared with previous surveys. The extra five hauls were part of a redesign of the survey on the main trawl ground which consisted of sub-division into two boxes, one having 15 and the second 10 randomly allocated stations. In addition the survey was conducted on a new vessel, the FV Atlas Cove, following the retirement of the previous vessel, the FV Southern Champion, which had been used for all previous surveys. Other sampling protocols, including the net used were identical to previous surveys.

    The catch rate of D. eleginoides was twice that of 2014 and two and a half times that of the long-term average for the survey. The C. gunnari catch rate was at about half the average. For the managed bycatch species catch rates were higher than the average for C. rhinoceratus, macrourids and skates, but lower for L. squamifrons. The catch of invertebrates in the 2015 survey was 4.6 t, with the most abundant taxa being jellyfish and the poriferan sponges. Invertebrate catches were smaller the long-term average.

    Length measurements were taken for nearly 23,000 fish and biological measurements for nearly half of those. Otoliths were collected from 1,599 D. eleginoides and over 500 toothfish were tagged and released. The extra focus on bycatch species this year meant that 333 sets of otoliths were collected for L. squamifrons,  499 for C. rhinoceratus and 929 for macrourids.