The UK undertook a bottom trawl survey of CCAMLR Subarea 48.3 on the FV Robin M Lee from 7th to 17th May 2021. Seventy-seven random trawls were completed covering depths of 105 to 354 m, including 20 at Shag Rocks, 27 in the NW, 14 in the SW, 6 in the SE and 10 in the NE. The biomass of mackerel icefish, Chamsocephalus gunnari, was estimated at 18,013 tonnes with a lower 1-sided 95% interval estimate of 10,627 tonnes. This is one of the lowest biomass estimates in the survey series. The highest catches were in the SW area, with low catches in the NW area, that are the main commercial fishing grounds and usually have the largest survey catches.
Catches of juvenile toothfish (Dissostichus eleginoides) were good, with almost 500 kgs caught in total. Catches were dominated by fish of 40-50 cm TL, but with some smaller fish also caught. Estimated biomass for the other species, such as the icefish Pseudochaenichthys georgianus and Chaenocephalus aceratus, and Gobionotothen gibberifrons were similar to previous surveys. Whilst the total catch of Notothenia rossii was less than 2019, the species was caught in a high proportion of trawls.
During two nights of calm weather to the south of the island, the vessel had significant bird collision events, with more than 200 birds found on the vessel on the night of the 15/16 May. The majority of the birds were diving petrels and were released alive and uninjured, but four diving petrels were killed.