Deep-Diving California Sea Lions: Are they Pushing their Physiological Limit
Abstract
The 500-m diving capacity of the California sea lion (Zalophus californianus) represents a model in which a generally considered shallow-diving species is potentially approaching its physiological limit during dives greater than 300 m in depth. The physiology of these extreme dives is relevant to the development of the sea lion as a model for deep-diving physiology and to the performance and training of California sea lions used as part of the U.S. Navy s Marine Mammal Program. In addition, the limits of a species physiological response to diving, especially during extreme dives, is key to understanding how the animal may respond to disturbances in the environment (i.e., sound, temperature, prey availability). In this study we will determine the rate and magnitude of O2 store depletion during dives, and investigate its relationship to heart rate and workload, thereby improving our understanding of O2 management during diving, specifically the role of lung O2 stores and O2 delivery to tissues. This study will utilize backpack digital recorders to measure blood oxygen depletion, heart rate, and flipper stroke rate in dives of California sea lions during maternal foraging trips to sea from San Nicolas Island. The goals of this research are 1) determination of the rate, pattern and magnitude of blood O2 store depletion during both shallow and deep dives at sea, 2) documentation of heart rate profiles of shallow and deep dives, and assessment of the relationship between changes in heart rate to blood O2 profiles, and 3) documentation of flipper stroke rate profiles during shallow and deep dives, and assessment of the relationship of stroke rate to both changes in heart rate and changes in blood O2 profiles.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 2013
- Accession Number
- ADA599008
Entities
People
- Birgitte I McDonald
- Paul J. Ponganis
Organizations
- Scripps Institution of Oceanography