The stock of Antarctic toothfish (D. mawsoni) in CCAMLR subarea 48.4 is estimated from tagging returns to be 982 tonnes in 2018. Applying the CCAMLR agreed precautionary assumption of average biomass across the time series and harvest rate of γ = 0.038, implies a 2018/19 yield of 37 tonnes, unchanged from the 2017/18 catch limit.
Historically, a precautionary approach has been applied in treating the 48.4 Antarctic toothfish as a separate stock. Based on the biological characteristics of the catches in Subarea 48.4, and the surrounding regions, the Antarctic toothfish around the southern South Sandwich Islands are now hypothesised as being part of a much larger stock that extends south into Subarea 48.2, 48.6 and possibly 48.5. The current method of assessment, based on tag returns, consequently, is considered to provide an estimate of the local biomass.