Tagging gives unprecedented insight to bluefin migration

One tag stayed in place for 391 days

July 2010: A tuna tagging project has revealed unprecedented insights into the behaviour of bluefin tuna in the Mediterranean.

The new understanding of the migratory behaviour of this enigmatic species made possible by WWF's On the Med tuna trail research will help make fisheries management more sustainable.

Starting in 2008, several tagging expeditions were carried out across the Mediterranean to determine Atlantic bluefin tuna trajectories and behaviour. That year tagging activities were centred on the western Mediterranean, while in 2009 the project expanded to the Adriatic Sea area, where tagging with ‘pop-up' satellite tags on wild adult tuna had never taken place before. Internal archival tags were used for juvenile tunas.

One 2008 archival tag was recovered after the tuna had roamed free for 391 days, providing unprecedented information on bluefin migratory behaviour for a full year's life cycle.

None of the tagged tunas left the Mediterranean Sea during the whole tracking period, while results even suggest a residence pattern for large adults north of the Balearic Islands in late summer - as well as a link between the Gulf of Lions and the Tyrrhenian Sea, and between the Adriatic Sea and the Libyan coast.

‘These results of WWF's tuna tagging work in the Mediterranean Sea have provided surprising and valuable insights into bluefin behaviour,' said Dr Sergi Tudela, Head of Fisheries at WWF Mediterranean.