Distribution of juvenile loggerhead turtles in the Western Pacific

Since 2006, the Aquarium has been working in collaboration with the Honolulu Laboratory of the National Marine Fisheries Service of Hawaii on a study of the migration of loggerhead turtles.

Two adult females were fitted with satellite transmitters (ARGOS), one in February 2007 and one in 2011. Their movements were thus monitored from their nesting site (Bourail, New Caledonia) to their feeding grounds on the other side of the Coral Sea, North East Australia.

During the night of 6 to 7 February, 2012, the Aquarium and the Association Bwärä were able to fit a satellite transmitter to the back of a loggerhead turtle on the beach at Bourail.

This adult female, measuring 89.4 cm, had come up the beach to lay her eggs, but was unable to do so, having been stopped by a dune of hard compacted sand. It was observed again, a couple of days later and still carrying its transmitter, when it returned to the beach to lay, this time successfully. An electronic chip was implanted for identification. Released early the next morning, it went back to sea and its travels have been followed by satellite tracking ever since.

 

This operation was the first step of a larger study in which juvenile turtles, raised in the Aquarium, are released at 18 months and their movements tracked by satellite. A first batch of 42 turtles were released in September 2008, and 46 more have just been released in september 2012. Their tracks can be followed on the maps updated regularly.

Initial results have shown that the major parameters affecting the presence and track of young turtles in the open ocean are temperature, magnetic field and current (measured by altimetry).

The study has also drawn maps of preferred habitats (Kobayashi et al., 2011).

A model of the distribution of turtles at age 1 year was derived from the data.

 

The animated map below shows the history of the migration of the young turtles towards Australia (2008).