Eastern Pacific populations of the leatherback turtle (Dermochelys coriacea) have declined by over 90%
during the past three decades. The decline is primarily attributed to human pressures, including
unsustainable egg harvest, development on nesting beaches, and by-catch mortality. In particular, the
effects of climate change may impose additional stresses upon already threatened leatherback populations.
This study analyzes how the pelagic habitat of Eastern Pacific leatherbacks may be affected by
climate change over the next century. This population adheres to a persistent migration pattern;
following nesting at Playa Grande, Costa Rica, individuals move rapidly through equatorial currents and
into foraging habitat within the oligotrophic South Pacific Gyre. Forty-six nesting females were fitted
with satellite tags. Based on the turtle positions, ten environmental variables were sampled along the
tracks. Presence/absence habitat models were created to determine the oceanographic characteristics of
the preferred turtle habitat. Core pelagic habitat was characterized by relatively low sea surface
temperatures and chlorophyll-a. Based on these habitat models, we predicted habitat change using
output from the Geophysical Fluid Dynamics Laboratory prototype Earth System Model under the Special
Report on Emissions Scenario A2 (business-as-usual). Although the model predicted both habitat losses
and gains throughout the region, we estimated that overall the core pelagic habitat of the Eastern Pacific
leatherback population will decline by approximately 15% within the next century. This habitat
modification might increase pressure on a critically endangered population, possibly forcing distributional
shifts, behavioral changes, or even extinction.