We attach very small satellite tracking devices, or tags, to neonate sea turtles to find out where their nursery areas are. Once we have devised a satisfactory way to attach the tags, we take the young turtles out to sea, release them and field-test the tags. This step involves releasing one or two turtles into the water with their tags and observing them swim, dive, come up to breathe and float.
Where we work, in Florida, USA, the sites are 15–20 kilometres offshore in the fast-moving Gulf Stream, where the water is clear and the sea floor is 800 metres below. This is familiar territory for our turtles and they swim away apparently unfazed. Watching the small turtles descend into blue water is a key part of the exercise. When they surface to take a breath we can check that the tags are holding fast and then leave them to do what comes naturally.
For us scientists it is a rewarding part of our work to watch the young turtles swim to freedom. Soon each one will be sending home, by means of its tiny antenna, messages of its travels.