Marine Resources Assessment for the Marianas Operating ... - SPREP

AUGUST 2005 FINAL REPORT
levels in water are relatively high at 160 to 200 dB with a reference pressure of one dB re 1 µPa-m
(Lenhardt 1994). Not only are sea turtles receptive to sounds, they also emit sounds. Nesting leatherback
turtles produce sounds in the 300 to 500 Hz range (Mrosovsky 1972).
For more information on the biology, life history, and conservation of sea turtles, the following websites
can be consulted: seaturtle.org (http://www.seaturtle.org), the Caribbean Conservation Corporation
(http://www.cccturtle.org), and the Archie Carr Center for Sea Turtle Research (http://accstr.ufl.edu/
index.html). Other important resources include NOAA Fisheries and USFWS authored sea turtle recovery
plans (http://www.nmfs.noaa.gov/prot_res/ PR3/recovery.html), NOAA Fisheries compiled Proceedings of
the Annual Symposia on Sea Turtle Biology and Conservation (http://www.nmfs.noaa.gov/prot_res/
PR3/Turtles/symp osia.html), Bjorndal (1995), Lutz and Musick (1997), and Lutz et al. (2003).
3.2.2 Sea Turtles of the Marianas MRA Study Area
Four of the world’s seven living species of sea turtles have been reported in the waters around Guam and
the CNMI (Pritchard 1995; NMFS and USFWS 1998a, 1998b, 1998c, 1998d; Kolinski 2001). These
include the green (Chelonia mydas), hawksbill (Eretmochelys imbricata), leatherback (Dermochelys
coriacea), and olive ridley (Lepidochelys olivacea) turtles. The loggerhead turtle (Caretta caretta) is also
known to occur in the North Pacific Ocean but has never been sighted in the Marianas region (NMFS and
USFWS 1998e). However, due to this species’ wide-ranging nature, there is a slight possibility that it
could occur in this region. As a result, a total of five sea turtle species are known to occur, or have the
potential to occur, in the Marianas MRA study area (Table 3-2).
Table 3-2. Sea turtle species known to occur or potentially occurring in the Marianas MRA study
area. Taxonomy follows Pritchard (1997). [ 1 A species’ occurrence in the study area can be described as one
of the following: Regular⎯occurs as a regular or normal part of the fauna in the study area, regardless of how
abundant or common it is; Rare⎯occurs in the study area sporadically; or Extralimital⎯does not normally occur in
the study area and occurrences there are considered beyond the species’ normal range; 2 As a species, the green
turtle is listed as threatened. However, the Eastern Pacific nesting stock is listed as endangered. Since the nesting
areas for green turtles encountered at sea often cannot be determined, a conservative approach to management
requires the assumption that at least some of the greens found in the study area could be endangered].
Scientific Name ESA Status Occurrence 1
Order Testudines (turtles)
Suborder Cryptodira (hidden-necked turtles)
Family Cheloniidae (hard-shelled sea turtles)
Green turtle Chelonia mydas Threatened 2 Regular
Hawksbill turtle Eretmochelys imbricata Endangered Regular
Loggerhead turtle Caretta caretta Threatened Rare
Olive ridley turtle
Family Dermochelyidae (leatherback sea turtle)
Lepidochelys olivacea Threatened Rare
Leatherback turtle Dermochelys coriacea Endangered Rare
The threatened green turtle is the only sea turtle species that is routinely observed during surveys around
Guam and the CNMI (Wiles et al. 1995; Kolinski et al. 1999; Pultz et al. 1999; Kolinski 2001). As a result,
some scientists have concluded that it is the only sea turtle species that is common to the area (Kolinski
et al. 1999; Pultz et al. 1999; Kolinski 2001). Kolinski (2001) notes that the other resident sea turtle of the
Marianas archipelago, the endangered hawksbill turtle, should be classified as extremely rare. However,
others believe that hawksbill turtles are not rare inhabitants of the study area and vicinity, even though
they are far less abundant than green turtles (Wiles et al. 1995).
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