EPA's Vessel General Permit and Small Vessel General

Leatherback sea turtle (Dermochelys coriacea)
Species description and distribution
The leatherback is the largest of all sea turtles (up to 916 kg; Eckert & Luginbuhl 1988) and
the only species lacking a hard, bony carapace. Its slightly flexible carapace is made primarily of
tough, oil saturated connective tissue. The species has an extensive distribution, ranging from
tropical to subpolar latitudes. This unique reptile is able to withstand broad temperature
extremes because of its large body size (Paladino et al. 1990), thick peripheral insulation (Goff
and Stenson 1988), counter-current heat exchange (Greer et al. 1973), and thermoregulatory
behavior (Bostrom et al. 2010).
Status
The leatherback sea turtle has been listed as endangered under the ESA since 1973 and, prior to
that, under the Endangered Species Conservation Act (35 FR 8491). The species is considered to
be critically endangered worldwide (Sarti Martinez 2000).
Population designations, abundance, and trends
The global population of adult females has declined over 70 percent in less than one generation,
from an estimated 115,000 adult females in 1980 to 34,500 adult females in 1995 (Pritchard
1982, Spotila et al. 1996), driven by dramatic reductions in several Pacific populations (Sarti
Martinez 2000). Nesting aggregations occur in six broad geographic regions: eastern Atlantic,
western Atlantic, eastern Pacific, western Pacific, and Indian. Genetic studies indicate the
reproductive isolation of these designations, which are distinguished by the presence of unique
mitochondrial DNA haplotypes or significant differences in haplotype frequencies (Dutton et al.
1999, Dutton et al. 2007).
Eastern Atlantic. In 2007, the Turtle Expert Working Group provided a population estimate of
34,000-94,000 adult leatherbacks in the North Atlantic Ocean (TEWG 2007), including both
eastern and western Atlantic stocks. Based on genetic and tagging data, there are at least two
stocks (eastern and western Atlantic) and possibly as many as seven (TEWG 2007). Nesting
occurs in the eastern Atlantic, from Mauritania to Angola (Fretey et al. 2007). Gabon hosts the
world’s largest population of leatherbacks, estimated at 15,730- 41,373 females (Witt et al.
2009). Population dynamics are relatively stable in the Atlantic, but estimates fluctuate
considerably due to individual variance in remigration intervals, clutch number, and inconsistent
nest site fidelity (TEWG 2007).
Western Atlantic. In 2007, the Turtle Expert Working Group provided a population estimate of
34,000-94,000 adult leatherbacks in the North Atlantic Ocean (TEWG 2007), including both
eastern and western Atlantic stocks. In the western Atlantic and Caribbean Sea, nesting occurs
on beaches in Puerto Rico, St. Croix, Costa Rica, Panama, Colombia, Trinidad and Tobago,
Guyana, Sao Tome and Principe, French Guiana, Suriname, and Florida (Márquez 1990, Spotila
et al. 1996, Bräutigam and Eckert 2006). Population dynamics are relatively stable in the
Atlantic, but estimates fluctuate considerably due to individual variance in remigration intervals,
clutch number, and inconsistent nest site fidelity (TEWG 2007).
Eastern Pacific. In the eastern Pacific, the estimated number of adult females declined by from
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