Chemical marking protocols for Antarctic starry skate age validation

A field study is planned to validate the thorn ageing method for Antarctic starry skate (Amblyraja georgiana). This study is a fast, simple ‘add-on’ that will complement the aims of the skate tagging programme. The antibiotic terramycin (oxytetracycline hydrochloride, OTC) will be injected into skates brought into the boat for tagging during the 2019-20 skate tagging programme in the Ross Sea. Injections will be made intra-muscularly in the wings and/or the lateral tail base using a 1 ml auto-injector gun at a dose rate of 25 mg per kg of skate (± 10 mg/kg). Recaptured skates should be frozen whole, or a selection of caudal thorns removed and frozen, and returned to Wellington for lab analysis. The injection equipment and materials can be readily sourced from manufacturers provided by participating members. If necessary, New Zealand can provide injection equipment and terramycin to vessels transiting New Zealand prior to the 2019 fishery to encourage participation in this programme.