Pretend to be a turtle:
The almost finalized version of the tag, whose design was entirely revised by the Ifremer and LIRMM (Montpellier Laboratory of Computer Science, Robotics and Microelectronics) teams (see Newsletter # 5), was put to the test in the open sea thanks to the help of some rather special divers. Two divers from the Indian Ocean delegation of Ifremer, Blandine and Magali, played the role of two sea turtles equipped with the tags.
For this test, three instruments were attached to the diving tanks:
- a high definition SBL (Short Baseline) acoustic system which transmits information from the surface to the autonomous board allowing the geolocation of divers to the nearest centimetre;
- an “openLogger” IOT system consisting of an accelerometer, a magnetometer and a gyroscope that measure acceleration, magnetic field and orientation in addition to speed and depth. These data will then be used to estimate a trajectory based on different algorithms;
This system is used to test the electronics of the IOT tag;
- an IOT logger system consisting of an accelerometer and a magnetometer which allows the data to be compared with that recorded by the openlogger system.
The objective of this test, carried out at Cap Lahoussaye in Reunion Island, was for divers to simulate the behaviour of a turtle equipped with an electronic IOT system in order to define the communication range of these new tags coupled with the autonomous board. The data collected will be used to analyse the underwater trajectories of the turtles.
To get as close as possible to the behaviour and movements of a sea turtle, the divers moved in breaststroke movements, alternating between swimming and resting phases on the seabed following a predefined circuit and timing within a 100-metre radius of the USV board in order to obtain the most precise and relevant geolocation possible.
First turtle deployments underway:
From 17 May to 24 June 2021, three members of the joint Ifremer-LIRMM team travelled to the island of Europa to carry out the first deployments of the final version of the IOT tag on one of the four study sites of the project. The objective of this second mission on Europa is to tag 8 juvenile green and/or hawksbill turtles with the new tags.