EPA's Vessel General Permit and Small Vessel General

Life history
The best estimate of age at sexual maturity for hawksbill sea turtles is about 20-40 years
(Chaloupka and Limpus 1997, Crouse 1999a). Reproductive females undertake periodic (usually
non-annual) migrations to their natal beach to nest. Movements of reproductive males are less
well known, but are presumed to involve migrations to their nesting beach or to courtship
stations along the migratory corridor (Meylan 1999). Females nest an average of 3 – 5 times per
season (Meylan and Donnelly 1999, Richardson et al. 1999). Clutch size is larger on average (up
to 250 eggs) than that of other sea turtles (Hirth 1980). Hatchlings migrate to and remain in
pelagic habitats until they reach approximately 22-25 cm in straight carapace length (Meylan
1988, Meylan and Donnelly 1999). As juveniles, they take up residency in coastal waters to
forage and grow.
Habitat
Hawksbill sea turtles are highly migratory and use a wide range habitats during their lifetimes
(Musick and Limpus 1997, Plotkin 2003). Small juvenile hawksbills (5-21 cm straight carapace
length) have been found in association with Sargassum spp. in both the Atlantic and Pacific
Oceans (Musick and Limpus 1997) and observations of newly hatched hawksbills attracted to
floating weed have been made (Hornell 1927, Mellgren et al. 1994, Mellgren and Mann 1996).
Juvenile hawksbills may occupy a range of habitats that include coral reefs or other hard-bottom
habitats, sea grass, algal beds, mangrove bays and creeks (Musick and Limpus 1997, Bjorndal
and Bolten 2010), and mud flats (R. von Brandis, unpublished data in NMFS and USFWS 2007).
As adults, hawksbills are typically associated with coral reefs, which are among the world’s most
endangered marine ecosystems (Wilkinson 2000). Individuals of multiple breeding locations can
occupy the same foraging habitat (Bowen et al. 1996, Bass 1999, Diaz-Fernandez et al. 1999,
Bowen et al. 2007, Velez-Zuazo et al. 2008). Nesting sites appear to be related to beaches with
relatively high exposure to wind or wind-generated waves (Santana Garcon et al. 2010).
Diet
As adults, hawksbills feed on sponges and corals (Meylan 1988, Leon and Bjorndal 2002). Data
from oceanic stage hawksbills are limited, but indicate a diet of plant and animal material
(Bjorndal 1997).
Diving
Hawksbill diving ability increases with age and body size (Blumenthal et al. 2009). Hawksbills
have long dive durations, although dive depths are not particularly deep. Adult females along St.
Croix reportedly have average dive times of 56 min, with a maximum time of 73.5 min (Starbird
et al. 1999). Average day and night dive times were 34–65 and 42–74 min, respectively.
Immature individuals have much shorter dives of 8.6–14 min to a mean depth of 4.7 m while
foraging (Van Dam and Diez 1997).
Critical habitat
On September 2, 1998, NMFS established critical habitat for hawksbill sea turtles around Mona
and Monito Islands, Puerto Rico (63 FR 46693). Aspects of these areas that are important for
hawksbill sea turtle survival and recovery include important natal development habitat, refuge
from predation, shelter between foraging periods, and food for hawksbill sea turtle prey.
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