Breathing patterns indicate cost of exercise during diving and response to experimental sound exposures in long-finned pilot whales

• Published in: Frontiers in Physiology
• Main Authors: Isojunno, Saana, Aoki, Kagari, Curé, Charlotte, Kvadsheim, Peter, Miller, Patrick
• Other Authors: Office of Naval Research, University of St Andrews. Sea Mammal Research Unit, University of St Andrews. School of Biology, University of St Andrews. Scottish Oceans Institute, University of St Andrews. Marine Alliance for Science & Technology Scotland, University of St Andrews. Institute of Behavioural and Neural Sciences, University of St Andrews. Centre for Social Learning & Cognitive Evolution, University of St Andrews. Bioacoustics group
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Aerobic diving limit; Anthropogenic noise; Code:R; Dtag; Field Metabolic Rate (FMR); Globicephala melas; Respiratory rate; Sonar; QH301 Biology; QP Physiology; DAS; SDG 14 - Life Below Water; QH301; QP; Killer Whale; Killer whale
• Online Access: http://hdl.handle.net/10023/16335; https://doi.org/10.3389/fphys.2018.01462

This work was funded by NL Ministry of Defence, NOR Ministry of Defence, United States Office of Naval Research (N00014-08-1-0984, N00014-10-1-0355, and N00014-14-1-0390), and FR Ministry of Defence (DGA) (public market n°15860052). KA was supported by the Japan Society for the Promotion of Science Bilateral Open Partnership Joint Research Program. Air-breathing marine predators that target sub-surface prey have to balance the energetic benefit of foraging against the time, energetic and physiological costs of diving. Here we use on-animal data loggers to assess whether such trade-offs can be revealed by the breathing rates (BR) and timing of breaths in long-finned pilot whales (Globicephela melas). We used the period immediately following foraging dives in particular, for which respiratory behavior can be expected to be optimized for gas exchange. Breath times and fluke strokes were detected using onboard sensors (pressure, 3-axis acceleration) attached to animals using suction cups. The number and timing of breaths were quantified in non-linear mixed models that incorporated serial correlation and individual as a random effect. We found that pilot whales increased their BR in the 5-10min period prior to, and immediately following, dives that exceeded 31m depth. While pre-dive BRs did not vary with dive duration, the initial post-dive BR was linearly correlated with duration of >2 min dives, with BR then declining exponentially. Apparent net diving costs were 1.7 (SE 0.2) breaths per min of diving (post-dive number of breaths, above pre-dive breathing rate unrelated to dive recovery). Every fluke stroke was estimated to cost 0.086 breaths, which amounted to 80-90% average contribution of locomotion to the net diving costs. After accounting for fluke stroke rate, individuals in the small body size class took a greater number of breaths per diving minute. Individuals reduced their breathing rate (from the rate expected by diving behavior) by 13-16% during playbacks of killer whale sounds and their first ...