seaturtle.org : MTN : ARCHIVES : Sign In

Marine Turtle Newsletter 113:8, © 2006

Marine Turtle Newsletter-Online

First Report of Green, Chelonia mydas, and Kemp’s ridley, Lepidochelys kempii
Turtle Nesting on Wassaw Island, Georgia, USA

Kristina L. Williams, Michael G. Frick & Joseph B. Pfaller
Caretta Research Project, P.O. Box 9841, Savannah, Georgia 31412 USA
(E-mail: wassawcrp@aol.com -KLW, caretta05@aol.com -MGF)

The loggerhead sea turtle (Caretta caretta) is the most commonly observed marine turtle species to nest in Georgia, USA (Frick et al. 2002). Green turtles (Chelonia mydas) and leatherback turtles (Dermochelys coriacea) also nest within the state (Rabon et al. 2003; M. Dodd personal communication). To date, loggerhead turtles and a single leatherback turtle have been reported to nest on Wassaw Island (Chatham County), Georgia (Frick et al. 2002). Here, we report nesting by two additional sea turtle species on Wassaw Island: a green turtle and a Kemp’s ridley (Lepidochelys kempi). Additionally, we provide data on hatching success and hatchling size for both species as well as morphometric and epibiont data for each nester.

On 4 August 2003 the first green turtle to nest on Wassaw Island since monitoring began in 1973 was encountered at 2115 h. The turtle was tagged with inconel flipper tags (SSX-747/SSX-743) and a PIT tag (#407B1E0A7F) was implanted in her right-front flipper. She measured 102 x 97 cm (curved carapace length and width (CCL/CCW)) and hosted the following epibiont species: barnacles (Platylepas hexastylos and Chelonibia caretta) and leeches (Ozobranchus brachiatus).

The green turtle deposited 151 eggs, of which 144 hatched 60 days later (95.4 % hatch rate). The morphometrics and weights of twenty hatchlings were recorded. The average size (straight measurements using Vernier calipers) and weight, including range, of the hatchlings were as follows: mean carapace length = 51.4 mm (range = 49 - 54.5 mm), mean carapace width = 37.9 mm (35 - 40.5 mm), mean depth = 21.5 mm (20 – 23 mm), and mean weight = 30.0 g (29 – 39 g).

On 24 June 2005 we encountered a nesting Kemp’s ridley at 1400 h. The turtle was measured (71 x 74 cm CCL/CCW), tagged with inconel flipper tags (SSX-707/SSX-456) and implanted with a PIT tag in the right front flipper (#444F0C556A). Biopsy samples were taken from each side of the neck for isotopic analyses being conducted by the Archie Carr Center for Sea Turtle Research in Gainesville, Florida. The turtle was largely free of epibiota but did host a few specimens of the barnacle C. testudinaria along the sutures between costal scutes near the posterior region of the carapace.

The Kemp’s ridley laid 126 eggs of which 36 hatched 48 days later (29 % hatch rate). Four hatchlings that were encountered during nest excavation were weighed and measured. The average size and weight, including range, of the hatchlings were as follows: mean carapace length = 38.1 mm (37 – 40.5 mm), mean carapace width = 29.3 mm (27 – 32 mm), mean depth = 18 mm (17 – 19 mm) and mean weight = 17.1 g (16.1 – 18.2 g).

Records of sea turtle species, other than loggerheads, that have nested on beaches north of Florida have been reported before. Rabon et al. (2003) summarizes such accounts for leatherback turtles and Woodson and Webster (1999) present similar data for green turtles. Two reports by Anonymous (1992) and Bowen et al. (1994) describe nesting by Kemp’s ridleys in South Carolina and North Carolina, respectively. Ours is the first report of a Kemp’s ridley nesting in Georgia.

Interestingly, from 1973 to 2001, only loggerhead sea turtles were observed nesting on Wassaw Island. Since 2001, three additional species have been encountered nesting on the island. The factors surrounding this sudden increase in nesting sea turtle diversity on Wassaw Island are unclear. There are several possible reasons why these species have been documented for the first time on Wassaw Island. For instance, green and Kemp’s ridley nesting has increased dramatically in Florida and Mexico, respectively. The green turtle may be expanding its range to the north as nesting numbers increase in Florida. Similarly, increases in the Kemp’s ridley population in the Gulf of Mexico and northwest Atlantic may increase the chances of a random nesting event on the Atlantic coast.

Acknowledgements: We thank Randy Isbister, Charles Warnock, Robert A. Moulis, the U.S. Fish and Wildlife Service – Savannah Coastal Refuges, the Wassaw Island LLC., the Georgia Department of Natural Resources, Peter Eliazar and the Archie Carr Center for Sea Turtle Research. We also thank two anonymous reviewers for their helpful suggestions and revisions which improved the manuscript.

ANONYMOUS. 1992. First Kemp’s ridley nesting in South Carolina. Marine Turtle Newsletter 59:23.

BOWEN, M.W., T.A. CONANT & S.R. HOPKINS-MURPHY. 1994. Where are they now? The Kemp’s ridley headstart project. Conservation Biology 8:853-856.

FRICK, M.G., K.L. WILLIAMS & D.C. VELJACIC. 2002. A record of the northernmost, verified leatherback sea turtle nesting event on the East Coast of the USA. Marine Turtle Newsletter 97:12-13.

RABON, D.R., S.A. JOHNSON, R. BOETTCHER, M. DODD, M. LYONS, S. MURPHY, S. RAMSEY, S. ROFF & K. STEWART. 2003. Confirmed leatherback turtle (Dermochelys coriacea) nests from North Carolina, with a summary of leatherback nesting activities north of Florida. Marine Turtle Newsletter 101:4-8.

WOODSON, H.M. & W.D. WEBSTER. 1999. Chelonia mydas (Green turtle). Nesting distribution. Herpetological Review 30: 224-225.