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

AUGUST 2005 FINAL REPORT
Figure 3-4. The post-nesting migration of a female green turtle satellite-tagged near Hagåtña,
Guam in June 2000. The sea turtle’s movements were monitored via the ARGOS satellite system
under the funding of the Commander, U.S. Naval Forces Marianas (COMNAVMARIANAS). The last
recorded location occurred in November 2000 in the Panguataran Islands, Philippines. Map
adapted from: Gutierrez (2004).
locations throughout the island’s shelf (Davis n.d.; Wiles et al. 1995; DoN 2003a; Abraham et al.
2004). Recreational SCUBA divers regularly see green turtles at the following sites off Guam:
Boulder Alley, Ane Caverns, Napoleon Cut, Gab Gab I, and the Wall (Franko’s Maps 2005).
Green turtle nesting on Guam is most prevalent at the northern and southern ends of the island.
At present, the Guam DAWR regularly surveys eight separate stretches of beach for green turtle
nesting activity (Gutierrez 2004). The most utilized nesting beaches at Guam are Tarague Beach,
Falcona Beach, Ritidian Beach, Asiga Beach, Urunao Point, and the beaches along Cocos Island
and Sella Bay (Davis n.d.; Pritchard 1995; Wiles et al. 1995; Gutierrez 2004). However, beaches
that are not currently being surveyed could be equally as important.
At Tinian, green turtle abundance and density are highest along the island’s relatively uninhabited
east coast. The most recent estimate of the number of green turtles inhabiting the nearshore
waters around Tinian was 832 turtles in 2001 (Kolinski et al. 2004). Green turtle numbers are
projected to be higher at Tinian than at Saipan, even though Saipan is a larger island with more
extensive seagrass habitats. The presence of seagrasses around Tinian is limited, so green
turtles occurring there likely feed on algae. At least 24 known forage species of algae were found
at Tinian during recent habitat surveys (Kolinski 2001). Since only juvenile age classes feed
primarily on algae, it is likely that Tinian does not serve as a resident foraging ground for adult
green turtles (Pultz et al. 1999). However, nesting surveys have indicated that adult green turtles
utilize most, if not all, beaches on Tinian for nesting (NMFS 1998). The beaches that are most
often utilized are Unai Dangkolo (Long Beach), Unai Barcinas, Unai Leprosarium, and Unai
Lamlam (Pultz et al. 1999; DoN 2005a; Figure 3-3). In 1995, an adult green turtle nesting at
Tinian was later recovered in the Philippines. This event provided evidence that adult green
turtles nesting in the Marianas archipelago have geographically distinct foraging grounds that are
often located thousands of kilometers away. In June 2002, a team of personnel from the Navy,
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