Characterisation of the toothfish fishery in the Ross Sea region through 2020/21

This paper summarises fishing catch and fishing effort in the Ross Sea region (Subarea 88.1 and Small-Scale Research Units (SSRUs) 88.2A-B)) together with biological characteristics of the catch of Antarctic toothfish (Dissostichus mawsoni) up to and including the 2020–21 fishing season. The implementation of the Ross Sea region Marine Protected Area (RSrMPA) from 1^st December 2017 has concentrated subsequent fishing on the continental slope south of 70° S, with recent fishing effort extending east into SSRUs 88.2A-B. Scaled annual length and age distributions of the catch show several modes of strong recruitment progressing through time on the slope (south of 70°), while the size and age distributions in the north have not changed. There was a small change in the sex ratio of Antarctic toothfish, with a gradual pattern of more males caught in all areas until 2015. The number of Antarctic toothfish recaptured in 2020–21 was higher than the average annual number over the past decade, likely a consequence of the concentration of fishing effort on the Ross Sea slope with the implementation of the RSrMPA. In 2021, a tagged fish was recaptured after 17 years at liberty.