Eretmochelys imbricata (Linnaeus, 1766)

Meylan, Peter A., Meylan, Anne B. & Gray, Jennifer A., 2011, The Ecology And Migrations Of Sea Turtles 8. Tests Of The Developmental Habitat Hypothesis, Bulletin of the American Museum of Natural History 2011 (357), pp. 1-70 : 49

Eretmochelys imbricata

BERMUDA: Only two recaptures of Eretmochelys in Bermuda were made through 2005, one after four months and one after four years. The hawksbill recaptured after four years was found in the same set of reefs where it had originally been tagged. Its very slow rate of growth (1 cm /yr) suggests that hawksbills that arrive in Bermuda at approximately 20 cm SCL (see above) could reside there for periods of more than 30 years if this growth rate is typical and they stay to a size of 55 cm.

THE LITERATURE: Meylan (1999) suggest- ed that high rates of recapture of immature Eretmochelys on the foraging grounds where they were tagged indicate long-term residency in developmental habitats. At all sites report- ed in the literature (table 11), there was some evidence of residency or site fidelity. The most detailed study of immatures on a foraging ground is that of van Dam and Diez (1998a) at Mona Island, Puerto Rico. At this site, Eretmochelys that were recaptured an average of 465 ± 331 days after tagging had moved less than half a kilometer (0.45 ± 0.66 km). More detailed data using sonic tags for three immature hawksbills at Mona Island revealed home ranges between 0.07 and 0.21 km 2. These authors concluded that immature hawksbills at this site appear resident for periods of ‘‘at least several years’’. Limpus (1992) and Limpus et al. (2008) came to a similar conclusion about hawksbills on the southern Great Barrier Reef. They suggested that hawksbills there have home ranges that are restricted to a single reef and that individuals occupy small areas for extended periods that may regularly reach 10 years in length. Leon and Diez (1999) reported an average distance between capture and recapture sites for 36 hawksbills on the south coast of the Dominican Republic of 0.36 ± 0.32 km, less than that observed at Mona Island. Recapture rates of hawksbills at other foraging grounds dominated by immatures are consistent with the hypothesis that this species remains resident in a relatively small area over extended periods of time, at least on the order of 5– 10 years.