MTN 97:11 Apparent Beach Basking of an Atlantic Green Turtle (<i>Chelonia mydas</i>) at Dry Tortugas National Park, Florida

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Apparent Beach Basking of an Atlantic Green Turtle (Chelonia mydas) at Dry Tortugas National Park, Florida

Chad Smith
19852 Dayton Hollow Lane, Fergus Falls, MN 56537, U.S.A. (E-mail: chadsmith14@yahoo.com)

Dry Tortugas National Park (24°38' N, 82°52' W) is a remote cluster of islands located approximately 113 kilometers (70 miles) west of Key West, Florida in the Gulf of Mexico. The park encompasses seven islands within its 260 square kilometer (100 square mile) boundary. At 30 acres (12 ha), Loggerhead Key is the largest of the seven islands. The Dry Tortugas Sea Turtle Monitoring Program was initiated in 1995 to monitor and document all sea turtle nesting activity within the park. Since 1995, daily beach surveys have been performed during the green turtle (Chelonia mydas) and loggerhead turtle (Caretta caretta) nesting seasons.

On August 19, 2001, at approximately 11:30 a.m. EDT, a juvenile green turtle was observed just above the high tide line on the southeastern beach of Loggerhead Key at Dry Tortugas National Park (photos presented to editor and available from author). The event occurred shortly after high tide on the day of a new moon. The sex and exact length of the turtle were undetermined, but carapace length was estimated at 50 cm. Assuming it was injured, researcher Nicole Ryan lifted the turtle to examine it. The turtle began thrashing its flippers, at which time the researcher set it down and it rushed into the sea. The track width measured 55 cm. Two other crawls of the same width were found on the same day along the eastern side of Loggerhead Key, presumably earlier crawls from the same turtle. No other green turtle tracks were documented on park beaches during the 2001 nesting season.

It is the first time in seven years of daily beach monitoring at Dry Tortugas National Park that an apparent basking turtle has ever been documented. Green (1998) noted "It is noteworthy that apart from the avoidance behaviour of female green turtles on Ascension Island (Mortimer 1981) there are no accounts in the literature of basking in Atlantic green turtles."

Acknowledgements: Special thanks to Anne Meylan for sharing her vast knowledge of sea turtles as well as editing the text. Additional thanks to Russell Reardon for his editing skills.

GREEN, D. 1998. Basking in Galapagos green turtles. In: S.P. Epperly & J. Braun (Compilers). Proceedings of the Seventeenth Annual Sea Turtle Symposium. NOAA Technical Memorandum NMFS-SEFSC-415: pp. 60-62.

MORTIMER, J.A. 1981. Reproductive ecology of the green turtle, Chelonia mydas, at Ascension Island. Ph.D. diss., University of Florida, Gainesville. 162 pp.