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Marine Ecology Progress Series

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MEPS 318:255-262 (2006)  -  doi:10.3354/meps318255

Estimating body mass in leatherback turtles Dermochelys coriacea

Jean-Yves Georges1,*, Sabrina Fossette1,2

1Département d’Ecologie, Physiologie et Ethologie, Institut Pluridisciplinaire Hubert Curien, Centre National de la Recherche Scientifique, 23 rue Becquerel, 67087 Strasbourg, France
2Université Louis Pasteur, 4 rue Blaise Pascal, 67070 Strasbourg, France

ABSTRACT: Body mass is a major life-history trait and provides a scale for all living processes of organisms. Unfortunately body mass cannot be easily measured for many species, because of the logistical difficulties involved in actually catching and weighing them. This is particularly true for sea turtles, which are large vertebrates that spend most of their life at sea. Here, we developed a general linear model to predict body mass from 17 morphometric measurements obtained from 49 leatherback turtles Dermochelys coriacea nesting on Awala Yalimapo beach, French Guiana, South America. A stepwise backward analysis removing independent parameters with p > 0.001 indicated that body mass can be estimated with 93% accuracy by body mass (kg) = –709.146 + 3.391 MedianBodyCirc (cm) + 2.664SCCL (cm), where SCCL is the standard curvilinear carapace length and MedianBodyCirc is body circumference at half of SCCL. A sensibility test showed that this parsimonious model is robust, as estimated body mass may change by 0.7 to 1.3% for 1 to 2 cm changes in SCCL and by 0.9 to 1.7% for 1 to 2 cm changes in circumference. Leatherback turtles from French Guiana were larger and heavier than at all other nesting sites studied so far, suggesting either that gravid leatherbacks feed during the nesting season in French Guiana and/or that this species may exhibit site-specific growth strategies. Further studies are required to test these hypotheses, including implementation of similar simple models for other nesting populations, in order to better understand the life history of this endangered species.

KEY WORDS: Biometry · Body mass · Dermochely coriacea · General linear model · Leatherbackturtle · Life history · Meta-analysis · Sea turtles

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