Results from the groundfish survey conducted in CCAMLR Subarea 48.3 in January/February 2011

The 2011 groundfish survey took place at South Georgia and Shag Rocks on the FV Sil between the 27th January and 6th February 2011. 87 random hauls were completed, with good coverage across the shelf. Catch-weighted length frequencies of mackerel icefish indicated that 3+ sized fish dominated at Shag Rocks, however 1+ and 2+ sized fish were present in larger proportions at South Georgia. A mean biomass of 49,353 tonnes was estimated for mackerel icefish, with a lower 1-sided 95% CL of 31,373 tonnes. Euphausiidae was the dominant prey item in the mackerel icefish diet with increased dietary importance compared to 2009/2010. As seen during the 2009 and 2010 survey, icefish remained close to the bottom and very few acoustic marks were observed in the water column. Themisto sp. was the only other prey that made a substantial contribution to the diet, occurring in 39.47% of stomachs.

Catches of Patagonian toothfish were greater than in 2009 and 2010, with a large haul of 40-45cm fish (1.6t) around Shag Rocks. These fish are likely to be the same cohort that was evident at Shag Rocks in 2010 (fish were then 29-39cm age 2+).