  We present the first combined analysis of diving behaviour and dispersal
patterns in gravid leatherback turtles during 3 consecutive nesting seasons in
French Guiana. In total 23 turtles were fitted with Argos satellite
transmitters and 16 individuals (including 6 concurrently satellite-tracked)
were equipped with an electronic time-depth recorder for single inter-nesting
intervals, i.e. between two consecutive ovi-positions. The leatherbacks
dispersed over the continental shelf, ranging from the coastal zone to the
shelf break and moved over 546.2 $\pm$ 154.1 km (mean $\pm$ SD) in waters of
French Guiana and neighbouring Surinam. They mostly performed shallow (9.4
$\pm$ 9.2 m) and short (4.4 $\pm$ 3.4 min) dives with a slight diurnal pattern.
They dived deeper as they moved away from the coast suggesting that they were
predominantly following the seabed. Inter-nesting intervals could be divided
into two phases: during the first 75% of the time turtles spent at sea, they
dived on average 47 min h-1 before showing a lower and more variable diving
effort as they came back to the shore. The extended movements of leatherbacks
and the fine analysis of dive shapes suggest that in French Guiana leatherbacks
may feed during the inter-nesting interval, probably to compensate for the
energy costs associated with reproduction. This results in this endangered
species being exposed to high risks of interactions with local fisheries
throughout the continental shelf.

Populations and Evolution