Movement and growth of tagged Dissostichus eleginoides around South Georgia and Shag Rocks (subarea 48.3)

• Main Authors: Marlow, T.R., Agnew, D.J., Purves, M.G., Everson, I.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: CCAMLR 2003
• Subjects: Marine Sciences; Zoology; Ecology and Environment; Shag Rocks; Patagonian Toothfish
• Online Access: http://nora.nerc.ac.uk/id/eprint/12776/; http://www.ccamlr.org/en/publications/science_journal/ccamlr-science-volume-10/ccamlr-science-volume-10101-111

In 2000 the UK started a Patagonian toothfish (Dissostichus eleginoides) tagging program to investigate the spatial and temporal movement of fish and to validate otolith-based growth estimates. Approximately 2 260 toothfish have been tagged and released during groundfish surveys and CCAMLR observer trips. This includes about 900 that have been injected with either strontium chloride or oxytetracycline that places a permanent chemical marker on the otolith indicating the date of injection and release. To date, 51 fish have been recaptured, mostly around Shag Rocks where there is greatest fishing activity. Most of the fish recaptured to date were tagged and released during experimental pot fishing in 2000 and 2001, and have been at liberty from one to two years. Four fish were tagged and recaptured from the same longline vessel in 2002 after up to two months at liberty The fish tagged during the groundfish surveys may not yet be large enough to be available to the longline fishery and there have been no reported recaptures of these fish tagged at South Georgia or elsewhere in the South Atlantic. Similarly, D. eleginoides tagged and released on the Patagonian Shelf have not been recaptured at South Georgia. Fourteen tags have been recovered from a high seas area on the Patagonian Shelf at 42degreesS after about one,year at liberty from some opportunistic tagging carried out on a toothfish pot vessel in international waters at that latitude in 2001.