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Marine Turtle Newsletter 94:, © 2001
Link Between Green Turtles Foraging in Brazil and Nesting in Costa Rica?
Eduardo H.S.M. Lima1 & Sebastian Troëng2
1Projeto TAMAR-IBAMA, Caixa Postal 0162.592-990 Almofala-Ceará (E-mail: aruana@terra.com.br)
2Caribbean Conservation Corporation, Apdo. Postal 246-2050 San Pedro, Costa Rica (E-mail: sebasgre@racsa.co.cr)
The largest known foraging and nesting populations of green turtles (Chelonia mydas) in the Atlantic are found along the Caribbean coasts of Nicaragua and Costa Rica (Bjorndal et al. 1999, Hirth 1997). A recent analysis of male and female individuals from the foraging grounds in Nicaragua found that the majority of individuals came from the nearby nesting grounds of Tortuguero, Costa Rica with a small percentage coming from the Suriname nesting populations (Bass et al. 1998). Nesting females from Ascension and Suriname largely forage in waters off of Northeastern Brazil (Carr 1975; Pritchard 1976), hence one may expect to find relatively low-level exchange between these southern populations and that of Tortuguero. This was recently confirmed by a tag return of an individual turtle tagged on the Brazilian feeding grounds and later recaptured in Nicaraguan waters (Lima et al. 1999). Here we present data on a tag return of an adult green turtle that moved in the opposite direction: from Tortuguero to Brazil. On 7 February 2001, a dead green turtle in the early stages of decomposition was found on the beach of Goiabeiras located in the municipality of Fortaleza, Ceará (3° 43’ S, 38° 32’ W). An external inspection revealed several perforations in the neck from different fishing hooks. The turtle had two external inconel tags, bearing the numbers 83028 and 83029, attached to the front flippers, and it measured 107 cm in curved carapace length (CCL) and 93cm in curved carapace width (max). This turtle had been originally tagged on the nesting beach of Tortuguero (10º 35’ N, 83º 31’ W to 10º 21’ N, 83º 23’ W) on 25 March 1999, and at that time had a CCL of 106 cm. This individual was seen during nesting events on 7 and 20 April of the same year, but was never seen on the beach again after this date. The minimum distance traveled by the turtle between Tortuguero and Brazil was approximately 5000 km. We suggest that genetic studies, satellite telemetry, and capture-mark-recapture programmes be integrated together to provide information on the origin and behavior of sea turtles in foraging areas such as Ceará, Brazil.
Acknowledgements: We thank CCC research assistant Ana Maria Suárez (Colombia) for her skillful application of the Inconel tags that remained attached to green turtle 83028/83029 after almost two years. Bass, and Luiziane Moreira do Nascimento of IBAMA/Fortaleza who found and reported the turtle in Brazil. We also thank Peter Eliazar of the Archie Carr Center for Sea Turtle Research for facilitating exchanges of tag return information, and Matthew Godfrey for help. Projeto TAMAR-IBAMA is comanaged by the Fundação Pró-TAMAR and officially sponsored by Petrobras. The Frankfurt Zoological Society generously supports the work at the TAMAR station in Almofala.
Bass, A.L., C.J. Lagueux & B.W.Bowen. 1998. Origin of green turtles, Chelonia mydas, at “Sleeping Rocks” off the northeast coast of Nicaragua. Copeia 1998: 1064-1069.
Bjorndal. K.A., J.A. Wetherall, A.B. BOLTEN & J.A. Mortimer. 1999. Twenty-six years of green turtle nesting at Tortuguero, Costa Rica: An encouraging trend. Conservation Biology 13: 126-134.
Carr, A. F. 1975. The Ascension Island green turtle colony. Copeia 1975: 547-555.
Hirth, H.F. 1997. Synopsis of the Biological Data on the Green Turtle Chelonia mydas (Linnaeus 1758). Biological Report 97(1), August 1997, Fish and Wildlife Service, U.S. Department of the Interior, Washington, D.C. 120 pp.
Lima, E.H.S.M., C.J. Lagueux, D. Castro. & M.A. Marcovaldi. 1999. From one feeding ground to another: green turtle migration between Brazil and Nicaragua. Marine Turtle Newsletter 85:10.
Pritchard, P.C.H. 1976. Post-nesting movements of marine turtles (Chelonidae and Dermochelyidae) tagged in the Guianas. Copeia 1976: 749-754.