Meeting Abstract
65.4 Jan. 7 Comparing heat loss and O2 consumption rates in captive bottlenose dolphins (Tursiops truncatus) MEAGHER, E/M*; MCLELLAN, W/A; WILLIAMS, T/M; BLUM, J/E; PABST, D/A; UNC Wilmington; UNC Wilmington; UC Santa Cruz; UNC Wilmington; UNC Wilmington emm3005@uncw.edu
Measurements of heat loss have been used to estimate marine mammal metabolic rate (MR), but few studies have directly tested the accuracy of this experimental approach. This study compared MR, estimated by using multiple heat flux (HF, W/m2) measurements, to those measured via O2 consumption rate in two captive, adult male bottlenose dolphins under three different metabolic states [resting (n=11), post-feeding (n=11), post-exercise (n=7)]. HF measurements at the lateral body wall (thoracic, tailstock) and appendages (dorsal fin, pectoral flipper, flukes), and O2 consumption rates were collected near-simultaneously for each dolphin under each metabolic state. MR determined from total heat loss was calculated by multiplying body and appendage surface areas (m2) by HF from those sites. Resting MRs measured via HF were significantly lower than post-feeding and post-exercise MRs (p=0.0026; ANOVA), which were similar to each other. Resting and post-feeding MRs measured by O2 consumption were similar, but both were significantly lower than post-exercise MRs (p<0.0001; ANOVA). Across all metabolic states, there was a weak, but significant positive relationship between HF and O2 consumption MRs (p=0.0285; ANOVA). MRs estimated via HF were always lower than those measured using O2 consumption, but the relationship between these values was dependent upon metabolic state. Thus, it appears as though heat flux measurements can predict trends in MR, but not absolute MR, for captive bottlenose dolphins. Differences between the MR estimates obtained via HF and O2 consumption may be partially explained by heat losses not assessed in our study, such as waste excretion, and changes in vasomotor state caused by exercise that could affect HF measurements.
