Long-Term Nesting Beach Studies: Insights And Outcomes From The Tortuguero Program

Long-Term Nesting Beach Studies: Insights And Outcomes From The Tortuguero Program

Sebastian Troëng
Caribbean Conservation Corporation, Apartado Postal 246-2050, San Pedro, Costa Rica

Dr. Archie Carr began green turtle studies at Tortuguero, Costa Rica, in 1955. In 1959, he formed Caribbean Conservation Corporation that continues his work today. This presentation focuses on key findings from the long-term program that could not have been learned from shorter studies. Tagging of nesting females at Tortuguero has revealed reproductive longevity of up to 24 years for green turtles. At least 14 female green turtles have been observed to be reproductively active for more than 20 years.

Repeated carapace measurements show that female green turtles display very limited growth (more than 0.3 cm/year) once they are reproductively active. Long-term monitoring of remigration intervals has demonstrated modulated reproductive periodicity in green turtles, possibly influenced by environmental conditions. This would help to explain the large interannual variation in nest numbers observed at Tortuguero and other nesting beaches. Several important conclusions regarding the outcome of sea turtle conservation have been learned from the Tortuguero program. For late-maturing species such as green turtles, conservation efforts have to be sustained for decades to produce tangible results.

This emphasizes the need for long-term commitments to fund and implement conservation actions in order to recover reduced nesting populations. The Tortuguero program shows that the policy changes and economic incentives needed for successful sea turtle conservation can take decades to attain. At Tortuguero, long-term protection of the nesting beach and adjacent waters in order to reduce egg collection and turtle hunting have contributed to a remarkable 417% increase in green turtle nest numbers between 1971 and 2003.

Abstract of paper presented at 25th International Symposium, 2005