IN November 2011, Matt Lansdell of CSIRO Hobart received a package containing numbered plastic tags recovered from southern bluefin tuna (SBT) caught on Indonesian fishing grounds.
Two of the tags had been deployed 21 years earlier, on a 50-centimetre tuna caught off South Australia from the vessel Glenley 111. When recaptured, the tuna was about 185 cm in length and weighed about 124 kilograms. Another of the returned tags had been deployed 16 years earlier by retired volunteer with CSIRO, Clive Stanley.
Matt Lansdell helps to enter and maintain data in the ‘TAG Database’, the repository for all types of CSIRO tag release and recapture records dating back to the 1950s. Some 135,000 SBT have been released (tagged) since the late 1950s.
The tuna have been tagged as part of international research programs aimed at understanding the dynamics of tuna populations and providing a scientific basis for fishery management. The recapture rate from 1970s releases is less than 10 per cent, making November’s find particularly valuable. Recaptures occur across eastern longitudes from South Africa to New Zealand, but are most concentrated around southern and western Australia.
For enquiries about CSIRO’s tagging research or to report CSIRO tags found please email tags@csiro.au or visit http://www.cmar.csiro.au/tagging/. To view displays of tracks for selected marine animals tagged by the CSIRO and partner agencies go to: http://www.oceantracks.csiro.au/.
