1. Energy expenditure of freely swimming adult green turtles (Chelonia mydas) and its link with body acceleration.
- Author
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Enstipp, Manfred R., Ciccione, Stéphane, Gineste, Benoit, Milbergue, Myriam, Ballorain, Katia, Ropert-Coudert, Yan, Kato, Akiko, Plot, Virginie, and Georges, Jean-Yves
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GREEN turtle ,SEA turtles ,WILDLIFE conservation ,COLD-blooded animals ,AQUATIC animals ,ACCELEROMETRY - Abstract
Marine turtles are globally threatened. Crucial for the conservation of these large ectotherms is a detailed knowledge of their energy relationships, especially their at-sea metabolic rates, which will ultimately define population structure and size. Measuring metabolic rates in free-ranging aquatic animals, however, remains a challenge. Hence, it is not surprising that for most marine turtle species we know little about the energetic requirements of adults at sea. Recently, accelerometry has emerged as a promising tool for estimating activity-specific metabolic rates of animals in the field. Accelerometry allows quantification of the movement of animals (ODBA/PDBA, overall/partial dynamic body acceleration), which, after calibration, might serve as a proxy for metabolic rate. We measured oxygen consumption rates (V̇
O 2 ) of adult green turtles (Chelonia mydas; 142.1±26.9 kg) at rest and when swimming within a 13 m-long swim channel, using flow-through respirometry. We investigated the effect of water temperature (Tw ) on turtle V̇O 2 and tested the hypothesis that turtle body acceleration can be used as a proxy for V̇O 2 . Mean mass-specific V̇O 2 (sV̇O 2 ) of six turtles when resting at a Tw of 25.8±1.0°C was 0.50±0.09 ml min-1 kg-0.83 . sV̇O 2 increased significantly with Tw and activity level. Changes in sV̇O 2 were paralleled by changes in respiratory frequency (fR ). Deploying bi-axial accelerometers in conjunction with respirometry, we found a significant positive relationship between sV̇O 2 and PDBA that was modified by Tw . The resulting predictive equation was highly significant (r2 =0.83, P<0.0001) and associated error estimates were small (mean algebraic error 3.3%), indicating that body acceleration is a good predictor of V̇O 2 in green turtles. Our results suggest that accelerometry is a suitable method to investigate marine turtle energetics at sea. [ABSTRACT FROM AUTHOR]- Published
- 2011
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