A 2-year programme was implemented in the 2019/20 and 2020/21 fishing seasons in the Ross Sea region to tag and release skates for population size estimation and to validate the thorn ageing method for Antarctic starry skate (Amblyraja georgiana). The program has been largely successful to date, with a total of 8990 skates tagged and released during the two fishing seasons in the Ross Sea and Amundsen Sea regions. An additional 1147 skates were tagged and released voluntarily in the 2021/22 fishing season, including additional sampling in the Bellingshausen Sea, for a total of 10 137 skates tagged and released over the three fishing seasons. Recaptures from these releases will be used to monitor trends in population size through time with additional tagging occurring periodically. In the 2019/20 and 2020/21 fishing seasons, at least 2408 individuals were injected (27% of the total tagged skates in those years) with a chemical (either oxytetracycline hydrochloride or strontium chloride) to act as an age validation marker. Since the 2019/20 fishing season, a total of 104 skates tagged and chemically marked during the program have been recaptured. Results from the age validation experiments are ongoing.
We recommend the following:
- Conservation Measure 41-01, Annex 41-01/C, paragraph 2 (x) should remain as is to ensure skates are sampled and thorns retained.
- We encourage Members to collect thorns for analysis. Sampling protocols and contact details are provided in Appendix 2.
- Another 2-year pulsed tagging event be considered in approximately five years, as specified under the Ross Sea Data Collection Plan.