Energy expenditure of southern right whales varies with body size, reproductive state and activity level
Abstract
Quantifying the energy expenditure of animals is critical to understanding the cost of anthropogenic disturbance relative to their overall energy requirements. We used novel drone focal follows (776 follows, 185 individuals) and aerial photogrammetry (5372 measurements, 791 individuals) to measure the respiration rate and body condition loss of southern right whales (Eubalaena australis) on a breeding ground in Australia. Respiration rates were converted to oxygen consumption rate and field metabolic rate (FMR) using published bioenergetic models. The intra-seasonal loss in body condition of different reproductive classes (calves, juveniles, adults, pregnant and lactating females) was converted to blubber energy loss and total energy expenditure (TEE). Using these two metrics, we tested the effects of body size, reproductive state and activity level on right whale energy expenditure. Respiration rates and mass-specific FMR decreased exponentially with an increase in body size, as expected based on allometric scaling. FMR increased curvilinearly with an increase in swim speed, probably as a result of increased drag and increased locomotion costs. Respiration rates and FMR were 44% higher for pregnant and lactating females compared with those of adults, suggesting significant costs of fetal maintenance and milk production, respectively. The estimated FMR of adults based on their respiration rates corresponded well with the estimated TEE based on body condition loss. The rate of decline in body condition of pregnant and lactating females was considerably higher than expected based on respiration rates, which probably reflects the milk energy transfer from mothers to calves, which is not reflected in their FMR.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 01, 2023
- Source ID
- 10.1242/jeb.245137
Entities
People
- Fredrik Christiansen
- Kate R Sprogis
- Lars Bejder
- Maria Glarou
- Mia L K Nielsen
Organizations
- Aarhus Institute of Advanced Studies, Aarhus Universitet
- Aarhus Universitets Forskningsfond
- Aarhus University
- Framework Programmes for Research and Technological Development
- Murdoch University
- Office of Naval Research
- University of Exeter
- University of Hawaiʻi at Mānoa
- University of Western Australia
- World Wide Fund for Nature