THE WWF/GBYP MULTI-ANNUAL BLUEFIN TUNA ELECTRONIC TAGGING PROGRAM (2008-2013): REPERCUSSIONS FOR MANAGEMENT

SUMMARY During the duration of a multi-annual (2008-2013) bluefin tuna electronic tagging program, 130 electronic tags (99 pop-up satellite and 31 internal archival) were deployed in both adult and juvenile fish in the western and central Mediterranean and in the Atlantic coast of Morocco. For the 64 analyzed tuna, weight ranged from 17 up to 250 kg and time at liberty of their tags spanned from 19 up to 391 days. In the western and central Mediterranean, two behavioral patterns (migratory and resident) were observed to co-occur, and from all the tuna that were in the Mediterranean Sea at some point, none crossed over to the eastern Mediterranean basin. Noteworthy, none of the resident individuals left the Mediterranean during the whole tracking period. Furthermore, the occurrence of potential Mediterranean spawners in North Atlantic waters beyond the 45 o W was observed.