Report on a random stratified trawl survey to estimate distribution and abundance of Dissostichus eleginoides and Champsocephalus gunnari conducted in the Heard Island region (Division 58.5.2), May–June 2007

Since the commencement of commercial fishing in Australian waters on the Heard Island plateau in 1997 an annual random stratified trawl survey (RSTS) has been conducted to assess the stocks of Patagonian toothfish (Dissostichus eleginoides) and mackerel icefish (Champsocephalus gunnari). The 2007 survey had two main aims:
• to assess the abundance of juvenile and adult Dissostichus eleginoides on the shallow and deep parts of the Heard Island Plateau;
• to assess the abundance of Champsocephalus gunnari on the Heard Island Plateau.
The survey had the same design as the 2006 RSTS survey in the number of stations chosen for sampling in each stratum. This paper describes the conduct of the survey on the FV Southern Champion during June to July 2007 and the resulting catches and biological sampling. The most abundant species in the catch was D. eleginoides, followed by Lepidonotothen squamifrons, Channichthys rhinoceratus, C. gunnari and Macrourus sp. Catches of these 5 main fish species were very similar to those in 2006, with the exception of Lepidonotothen squamifrons which was much more abundant in 2007. Holothurians, poriferans, medusae and anemones were the most common invertebrate biota caught in the net.