ABSTRACT
This chapter will focus on the coastal and pelagic ocean habitats of leatherback turtles (Dermochelys coriacea) in terms of migration, foraging, physiology, and dive behavior with links to climate and oceanography. Satellite telemetry provides the framework by which scientists can track sea turtles in three dimensions such that crucial data can be acquired on migratory pathways, swim speed, dive behavior, and the ambient water temperature of the turtle’s marine environment. Whereas the oceanic habitats of loggerhead turtles are based on satellite-tracking studies of both males and females at multiple life history stages (Chapter 8), those of leatherback turtles are almost entirely based on the internesting and postnesting movements of mature females, with the exception of some regional studies that have tagged in-water adult and subadult males and females. The juvenile life history
7.1 Introduction .......................................................................................................................... 163 7.2 A Biophysical Oceanographic Context for Leatherback Prey: The Jellysh Diet ............... 164
7.2.1 Phytoplankton: The Base of the Marine Food Web ................................................. 164 7.2.2 Biological and Physical Controls of Gelatinous Zooplankton Biomass ................... 166
7.3 Migration and Foraging Areas ............................................................................................. 167 7.3.1 Adults ........................................................................................................................ 167
7.3.1.1 Western Atlantic Population ...................................................................... 167 7.3.1.2 Eastern Atlantic Population ....................................................................... 170 7.3.1.3 Western Indian Population ......................................................................... 170 7.3.1.4 Western Pacic Population ........................................................................ 171 7.3.1.5 Eastern Pacic Population ......................................................................... 172
7.3.2 Lost Years: Neonates and Juveniles .......................................................................... 172 7.3.3 Theoretical Ontogeny of Adult Migration/Foraging Area Fidelity .......................... 175 7.3.4 Adult Round-Trip Migration ..................................................................................... 176
7.4 Dive Behavior ....................................................................................................................... 177 7.4.1 Diel Vertical Migration ............................................................................................. 177 7.4.2 Foraging .................................................................................................................... 177 7.4.3 Thermoregulation ..................................................................................................... 179
7.5 An Oceanographic Context for Adult Foraging Hotspots .................................................... 179 7.5.1 Link between Diatoms, Temperature, and Leatherback Foraging Hotspots ............ 179 7.5.2 Oceanographic Fronts, Mesoscale Eddies, and Currents ......................................... 181
7.6 Bottom-Up Forcing and Climate Variability ........................................................................ 181 7.6.1 ENSO Inuence on Eastern Pacic Leatherbacks ................................................... 181 7.6.2 Interpopulation Differences in Phenotype, Fecundity, and Population Status ......... 183
7.7 Future Directions .................................................................................................................. 184 References ...................................................................................................................................... 185
stage of leatherbacks (curved carapace length [CCL] < 100 cm) is one of the biggest mysteries of sea turtle biology and has confounded researchers for decades. Therefore, the majority of the data presented in this chapter will be based on mature female leatherback studies although some work is presented on the in-water deployment of satellite tags of male and female subadults (CCL > 100 cm but not sexually mature), adults, and on the limited dataset of juvenile (CCL < 100 cm) sightings with inferences on their physiological constraints.
