Affiliation: | 1. Global Diving Research SL, Valencia, Spain;2. Clearwater Marine Aquarium, Clearwater, Florida Contribution: Investigation, Resources;3. Clearwater Marine Aquarium, Clearwater, Florida Contribution: Investigation, Resources, Supervision;4. Gulf World, Panama City Beach, Florida Contribution: Investigation, Resources, Supervision;5. The Dolphin Company, Cancún, Mexico Contribution: Investigation, Resources, Supervision;6. Kolmården Wildlife Park, Kolmården, Sweden Contribution: Data curation, Formal analysis, Investigation, Writing - review & editing |
Abstract: | We measured resting metabolic rate (RMR), tidal volume (VT), breathing frequency (fR), respiratory flow, and end-expired gases in rough-toothed dolphins (Steno bredanensis) housed in managed care after an overnight fast and 1–2 hr following a meal. The measured average (± standard deviation) VT (4.0 ± 1.3 L) and fR (1.9 ± 1.0 breaths/min) were higher and lower, respectively, as compared with estimated values from both terrestrial and aquatic mammals, and the average VT was 43% of the estimated total lung capacity. The end-expired gas levels suggested that this species keep alveolar O2 (10.6% or 80 mmHg) and CO2 (7.6% or 57 mmHg), and likely arterial gas tensions, low and high, respectively, to maximize efficiency of gas exchange. We show that following an overnight fast, the RMR (566 ± 158 ml O2/min) was 1.8 times the estimated value predicted by Kleiber for terrestrial mammals of the same size. We also show that between 1 and 2 hr after ingestion of a meal, the metabolic rate increases an average of 29% (709 ± 126 ml O2/min). Both body mass (Mb) and fR significantly altered the measured RMR and we propose that both these variables should be measured when estimating energy use in cetaceans. |