EPA's Vessel General Permit and Small Vessel General

turtles and eggs poses the most serious threat (NMFS & USFWS 1998). Many green sea turtles
exhibit fibropapillomatosis, a tumor forming disease, which may interfere with movement and
foraging (Aguirre and Lutz 2004). Very few green sea turtles are bycaught in U.S. fisheries
(Finkbeiner et al. 2011a), but low-level bycatch has been documented in longline fisheries
(Petersen et al. 2009). Hatchlings are preyed upon by seabirds and sharks; eggs are preyed upon
by dogs, pigs, rats, and crabs (Witzell 1981, Bell et al. 1994). Anthropogenic climate change
may further destroy nesting habitat via sea level rise and may cause the widespread failure of
nests via increased temperatures (Fuentes et al. 2010).
Life history
Female green sea turtles reach sexual maturity at 20 years of age or greater and reproduce for 17
– 23 years (Chaloupka and Musick 1997, Hirth 1997, Limpus and Chaloupka 1997, Zug and
Glor 1998, Seminoff et al. 2002b, Zug et al. 2002, Chaloupka et al. 2004)). They return to their
natal beaches to nest every 2 – 5 years (Hirth 1997) to deposit 1 – 7 clutches (usually 2-3) at 12-
14 day intervals. Mean clutch size is highly variable among populations, but averages 110-115
eggs/nest (Balazs 1983). Hatchlings emerge from the nest and orient towards a light source,
such as light shining off the ocean. Juvenile green sea turtles occupy pelagic, benthic, and
coastal foraging habitats until they mature and return to their natal beach for parturition (Carr et
al. 1978, Meylan et al. 1990). Green sea turtles exhibit slow growth rates, as a result of their
herbivorous diet (Bjorndal 1982). They reach a maximum size just under 100 cm in carapace
length (Tanaka 2009).
Migration and movement
Green sea turtles are highly mobile and undertake complex movements through geographically
disparate habitats during their lifetimes (Musick and Limpus 1997, Plotkin 2003). Green sea
turtles spend the majority of their lives in coastal foraging grounds, including open coastline and
protected bays and lagoons. Adult females migrate to their natal beaches to nest.
Diet
Green sea turtles are not obligate herbivores; they also forage on invertebrates especially as
juveniles (Godley et al. 1998, Heithaus et al. 2002, Seminoff et al. 2002a, Hatase et al. 2006,
Parker and Balazs in press). A shift to a more herbivorous diet occurs when individuals move
into neritic habitats, usually at 30 – 62 cm in carapace length (Cardona et al. 2010).
Diving
Based on the behavior of post-hatchlings and juvenile green turtles raised in captivity, we
presume that those in pelagic habitats live and feed at or near the ocean surface, and that their
dives do not normally exceed several meters in depth (NMFS and USFWS 1998, Hazel et al.
2009). The maximum recorded dive depth for an adult green turtle was just over 106 m
(Berkson 1967), while subadults routinely dive to 20 m for 9-23 min, with a maximum recorded
dive of over 1 h (Brill et al. 1995, I-Jiunn 2009).
Critical habitat
In 1998, critical habitat for green sea turtles was designated in coastal waters surrounding
Culebra Island, Puerto Rico (63 FR 46693). Aspects of these areas that are important for green
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