PRELIMINARY RESULT OF POP-UP ARCHIVAL TAGGING FOR ATLANTIC BLUEFIN TUNA (THUNNUS THYNNUS) RELEASED IN THE NORTHEASTERN ATLANTIC OCEAN

• Main Authors: Yasuko Semba, Yukio Takeuchi
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.534.3574; http://www.iccat.int/Documents/CVSP/CV064_2009/no_2/CV064020662.pdf

We report the preliminary analysis of migration of an Atlantic bluefin tuna which was tagged and released from the area off Ireland. This individual was caught on 29 September 2007 and released after the attachment of a pop-up archival tag (PAT) at the location (48º-16ºN, 11º-50ºW). The length estimated by eye was 160 cm (FL). On 29March 2008, this tag was popped off six months after the release as programmed, and transmitted the data for the past six months. This individual conducted transatlantic movement from the eastern to the western North Atlantic. Based on the distinct temporal pattern of maximum diving depth and average temperature (both on a daily basis), we identified three phases in movement pattern as follows. In the first phase (9/29-1/26), this individual stayed in a relatively limited area with shallow vertical movement in the warm water, and embarked on a long- distance movement to the west with deep vertical movement in the cold water in the second phase (1/27-2/6), and it stopped the large movement and stayed in the terminal area with shallow vertical movement in the cold water in the third phase (2/7-3/29). The oceanographic feature may be associated with this change of behavior, which needs to be confirmed in the future. In this result, the link between the eastern foraging ground and the western breeding area was not confirmed but the intercommunication between east and west in the Atlantic was supported. RÉSUMÉ