These two animations below detail the dynamics of preferred feeding habitat of the Atlantic Bluefin tuna (Druon et al., 2016) with, as an overlay, the locations of bluefin tunas equipped with an electronic tag (data not used to calibrate the model).
Atlantic bluefin tuna in the North Atlantic
This electronic tag was deployed by AZTI (Spain) on a juvenile bluefin tuna for two years. This exceptionally-long tag allowed to follow the fish migration between its summer feeding ground in the Bay of Biscay (NE Atlantic) and its winter exploration for new habitat in the Azores area on the first year and in the Canadian part of the Gulf Stream on the second year. The fish would certainly have fully crossed the Atlantic on the third year as the adults usually do following the Gulf Stream that acts as an ecological bridge.
Two electronic tags were deployed by IFREMER (France) during summer in the Gulf of Lions for one year on young adult bluefin tunas. This animation shows that both fish follow the seasonal habitat contraction and expansion as they spread in the Mediterranean Sea in winter and spring while they come back to the Gulf of Lions in summer, in the most important feeding ground as emphasized by the habitat prediction.
These seven regional Blue Shark animations overlay presence data (observer and electronic tagging) on the global habitat analysis by size and sex classes (Druon et al., in revision):
- North Atlantic Ocean: Small juveniles / Large juvenile females / Large juvenile males
- Northeast Pacific Ocean: Large juvenile females / Adult females / Adult males
- Indian and southwest Pacific oceans: Adult females
These habitat animations are derived from 14-day floating composites over 2003-2018.