Report of the UK Groundfish Survey at South Georgia (CCAMLR Subarea 48.3) in February 2023

The 2023 South Georgia Groundfish Survey took place over the South Georgia and Shag Rocks shelf on the FV Robin M Lee between the 1st and 10th of February 2023. Seventy-five random trawls were completed covering depths of between 106 and 332 m, including 19 at Shag Rocks, 26 in the north west, 11 in the south west, 8 in the south east and 11 in the north east. Overall biomass of mackerel icefish, Chamsocephalus gunnari, was estimated at 61,567 tonnes with a lower 1-sided 95% confidence interval estimate of 38,231 tonnes. This estimate is the highest biomass estimate since 2017 and the highest lower 1-sided 95% confidence interval since 2013. Catches of juvenile toothfish (Dissostichus eleginoides) were the highest since 2011, with almost 1340 kgs caught in total.  Catches of toothfish were dominated by fish of 40-47 cm TL, with at least two other cohorts present (one larger, one smaller). Estimated biomass for the other species, such as the icefish Pseudochaenichtys georgianus and Chaenocephalus aceratus, and Gobionotothen gibberifrons were all higher than 2021 but roughly in line with earlier surveys. During the first two days of the survey, two Antarctic toothfish (Dissostichus mawsoni) were caught, representing the first time this species has been found in the history of the survey (since 1988/89). It is likely they had moved to South Georgia from the South Sandwich Islands on a current of cold water and had become trapped by warmer deep water, which was recorded on net sensors