Fine scale geographic residence and annual primary production drive body condition of wild immature green turtles (Chelonia mydas) in Martinique Island (Lesser Antilles)

• Main Authors: Marc Bonola, Marc Girondot, Jean-Patrice Robin, Jordan Martin, Flora Siegwalt, Lorène Jeantet, Pierre Lelong, Clément Grand, Philippine Chambault, Denis Etienne, Julie Gresser, Gaëlle Hielard, Alexandre Arqué, Sidney Régis, Nicolas Lecerf, Cédric Frouin, Fabien Lefebvre, Emmanuel Sutter, Fabien Vedie, Cyrille Barnerias, Laurent Thieulle, Robinson Bordes, Christelle Guimera, Nathalie Aubert, Myriam Bouaziz, Adrien Pinson, Frédéric Flora, Matthieu Duru, Abdelwahab Benhalilou, Céline Murgale, Thomas Maillet, Lucas Andreani, Guilhem Campistron, Maxym Sikora, Fabian Rateau, Francis George, Joffrey Eggenspieler, Thierry Woignier, Jean-Pierre Allenou, Laurent Louis-Jean, Bénédicte Chanteur, Christelle Béranger, Jessica Crillon, Aude Brador, Caroline Habold, Yvon Le Maho, Damien Chevallier
• Format: Article
• Language: English
• Published: The Company of Biologists 2019-12-01
• Series: Biology Open
• Subjects: green turtles; juveniles; body mass; body condition; biometry
• Online Access: http://bio.biologists.org/content/8/12/bio048058

The change of animal biometrics (body mass and body size) can reveal important information about their living environment as well as determine the survival potential and reproductive success of individuals and thus the persistence of populations. However, weighing individuals like marine turtles in the field presents important logistical difficulties. In this context, estimating body mass (BM) based on body size is a crucial issue. Furthermore, the determinants of the variability of the parameters for this relationship can provide information about the quality of the environment and the manner in which individuals exploit the available resources. This is of particular importance in young individuals where growth quality might be a determinant of adult fitness. Our study aimed to validate the use of different body measurements to estimate BM, which can be difficult to obtain in the field, and explore the determinants of the relationship between BM and size in juvenile green turtles. Juvenile green turtles were caught, measured, and weighed over 6 years (2011–2012; 2015–2018) at six bays to the west of Martinique Island (Lesser Antilles). Using different datasets from this global database, we were able to show that the BM of individuals can be predicted from body measurements with an error of less than 2%. We built several datasets including different morphological and time-location information to test the accuracy of the mass prediction. We show a yearly and north–south pattern for the relationship between BM and body measurements. The year effect for the relationship of BM and size is strongly correlated with net primary production but not with sea surface temperature or cyclonic events. We also found that if the bay locations and year effects were removed from the analysis, the mass prediction degraded slightly but was still less than 3% on average. Further investigations of the feeding habitats in Martinique turtles are still needed to better understand these effects and to link them with geographic and oceanographic conditions.