Hawksbill and Green Turtles Studied in Hawaii’s Coastal Habitats

During the summer of 2009, Hawaii marine turtle research advanced on several fronts. In June, PIFSC staff joined colleagues from the Hawaii Preparatory Academy in a study of hawksbill turtles in nearshore reef habitat at Oneuli Black Sand Makena Beach Park on Maui. The scientists captured three hawksbills reported by the public to frequent this area. Before releasing the turtles back to the ocean, they measured and tagged them and obtained tissue samples for mtDNA and stable isotope analysis. Measured lengths indicated that two of the turtles (70 and 71 cm shell length) were subadults and the other (36 cm) a juvenile. The hawksbill is the least abundant of Hawaii’s marine turtles. During the 33 years of sea turtle ocean-capture research in Hawaii, only 12 hawksbills have been encountered and tagged and only 79 of over 5000 documented Hawaii sea turtle strandings have been identified as hawksbills.

Other research focused on Hawaiian green turtles. The annual assessment of green turtle nesting was completed at East Island, French Frigate Shoals, determining that 295 green turtles nested there in 2009. The estimate was based on a 36-night partial-season survey of nesting beaches during which 270 individual nesters were identified and tagged. The number of green turtles nesting at East Island has been estimated annually since 1973 based on partial-season surveys of nesting activity conducted collaboratively by the PIFSC Marine Turtle Research Program and the U.S. Fish and Wildlife Service. Estimates of nesting activity at East Island are used as an index of abundance for the Hawaiian green turtle population and to monitor recovery status. Although there is inter-annual variation in the estimated number of nesters, the long-term trend of increasing annual nesting continues for the population.

Students from Okinawa and the Hawaii Preparatory Academy 
            helped PIFSC zoologist George Balazs capture juvenile green turtles on the Kona Coast of Hawaii and collect 
            biological data for research.
Students from Okinawa and the Hawaii Preparatory Academy helped PIFSC zoologist George Balazs capture juvenile green turtles on the Kona Coast of Hawaii and collect biological data for research.

A group of students from Okinawa, Japan, was hosted by PIFSC and the Hawaii Preparatory Academy in a project to capture immature green turtles foraging along the Keawanui coastline of the island of Hawaii. The students helped conduct health screening of the turtles and tag them before release. The students’ participation in the field studies was a result of their winning an essay contest on the topic of environmental stewardship sponsored by the Okinawa Churaumi Aquarium. They were guided during their Hawaii visit by Takashi Ishihara, a Tokyo University PhD student.