1. The 2017 UK groundfish survey took place over the South Georgia and Shag Rocks shelf on the FV Sil between the 30th January – 7th February 2017.
2. 72 random hauls were completed covering depths of between 100 and 350m.
3. Overall biomass of Mackerel icefish (Champsocephalus gunnari) was calculated at 91,049 t with a lower 1-sided 95% interval estimate of 37,514t. Mackerel icefish density was highest on the fishing grounds on the moraine banks of the NW stratum.
4. Clear regional differences in C. gunnari diet composition were observed. Krill were almost absent from fish sampled at Shag Rocks, at low levels in the northern strata of South Georgia and more abundant in the Southern strata. Although comprising 42% of diet by mass across all strata, the index of relative importance (IRI%) for krill was low (18%) whilst the amphipod Themisto sp. dominated diets (IRI% 77%).
5. Catches of juvenile Dissostichus eleginoides were low. A small peak in the length frequency distribution was present at lengths of 58-63cm (TL) indicating the presence of a cohort of 5+ fish.
6. Estimated biomass for the other icefish species were very similar to results obtained in 2015. However, the estimated biomass of Notothenia rossi was lower than observed in 2015 but was still the third highest seen in the survey time series.
7. HD camera footage was obtained from a headline-mounted camera at 12 trawl locations.