WALLACE, B.P. ; PALADINO, F.V.; KILHAM, S.S.; SPOTILA, J.R.; Drexel University; Indiana-Purdue University, Fort Wayne; Drexel University; Drexel University : First Field Metabolic Rates for Dermochelys coriacea: Climate and Fisheries Deal a One-Two Punch to Pacific Leatherbacks

Leatherback turtles, Dermochelys coriacea, are critically endangered and their unique physiological and life history traits make quantification of their energetic requirements crucial to conservation of the species. However, metabolism of free-swimming marine turtles has never been measured. We used doubly labeled water (DLW) on adult female leatherbacks to obtain the first field metabolic rates (FMRs) for free-swimming marine turtles and used these FMRs to calculate the leatherback reproductive energy budget. The FMRs were within the range of reported values of resting metabolic rates for nesting leatherbacks and below values for active leatherbacks on land. These low FMRs suggest that leatherbacks use less energy while actively swimming than in their terrestrial activities. Using these data, we calculated the energy costs of reproduction, migration, and foraging activities. Our energy budget estimations indicate that resource limitation might lengthen remigration intervals for Pacific leatherbacks as compared to Atlantic leatherbacks, thus decreasing the Pacific population�s reproductive success and increasing its exposure to risk of pelagic fisheries mortality. Stochastic resource availability related to El Ni�o-Southern Oscillation (ENSO), combined with energetic constraints, is probably exacerbating the effects of a high incidental fisheries mortality rate currently responsible for plummeting Pacific leatherback populations. Therefore, management strategies for fisheries should be more conservative and allow little, if any, take of leatherbacks if there is to be any reasonable hope for recovery of this species.