Comparative Respiratory Physiology in Cetaceans.

Area of Science:

• Marine Mammal Physiology
• Comparative Respiratory Physiology
• Cetacean Biology

Background:

• Understanding cetacean respiratory physiology is crucial for assessing lung health and physiological limits.
• Previous studies have provided limited data on breath-by-breath respirometry in cetaceans.

Purpose of the Study:

• To evaluate respiratory physiology under voluntary control in beluga and false killer whales.
• To compare cetacean respiratory parameters with allometric predictions from terrestrial mammals.
• To establish allometric relationships for respiratory flow in cetaceans.

Main Methods:

• Breath-by-breath respirometry was employed in a beluga calf and false killer whales.
• Respiratory frequency (fR) and tidal volume (VT) were measured.
• Data were compared with published data from other cetacean species and terrestrial mammals.

Main Results:

• Beluga and false killer whales exhibited lower breathing frequency (fR) and significantly greater tidal volume (VT) than predicted for terrestrial mammals.
• Allometric mass-exponents for VT and fR in cetaceans were similar to those in terrestrial mammals.
• An allometric relationship for respiratory flow was identified, with expiratory flow averaging 30% higher than inspiratory flow.

Conclusions:

• Cetacean respiratory physiology differs from terrestrial mammals, particularly in tidal volume and breathing frequency.
• The study provides valuable data for understanding cetacean lung function and potential physiological limitations.
• Established allometric relationships enhance our ability to predict respiratory parameters in cetaceans.