Abstract

Electrocardiography (ECG) studies of dolphins have previously been performed,^1-4 but ECGs have not been routinely employed in field studies to monitor physiologic status during handling. A health assessment of bottlenose dolphins (Tursiops truncatus) was conducted by the National Oceanic and Atmospheric Administration (NOAA) in August 2009. This study took place near the Turtle/Brunswick River Estuary in Glynn County, Georgia, USA. The health assessment was designed to assess heavy metal and organochlorine exposure and its effects on dolphin health and movement patterns of individual dolphins in the study area. During this capture event, electrocardiography was utilized to monitor individual animals continuously during the sample collection procedures to determine their cardiovascular stability and ensure safer handling. The ECG readings were analyzed in real time for heart rate and rhythm disturbances. The ECG leads were attached using suction cups made of a soft silicone with embedded glass electrodes. These leads were placed on the body of the dolphins after they were brought aboard the processing boat. The first lead was placed cranial to the dorsal fin, while the other two leads were placed caudal to the pectoral fins. The lead wires were attached to a transmitter that was housed in a small waterproof case positioned next to the dolphin. The ECG data were sent wirelessly to a laptop computer in a water-safe zone of the boat where it was evaluated by a veterinarian. A stethoscope was used intermittently to monitor the animal's heart rate directly to compare the accuracy of the new technology. We were able to event mark the continuous ECG data with all sample procedures that were performed on the dolphin. These event marks were later evaluated to compare the individual dolphin's response to each procedure. Electrocardiography is useful for monitoring dolphin health during live capture procedures and could be used in conjunction with traditional monitoring of respiratory and heart rate.

This research was conducted under NMFS Scientific Research Permit Number 932-1905/MA-009526 and IACUC permit number HZ-2009-001.

References

1.  Hamlin RL, Jackson RF, Himes JA, Pipers FS, Townsend AC 1970. Electrocardiogram of bottle-nosed dolphin (Tursiops truncatus). Am J Vet Res 31:501-505.

2.  Noren SR, Cuccurallo V, Williams TM 2004. The development of diving bradycardia in bottlenose dolphins (Tursiops truncatus). J Comp Physiol B 174:139-147.

3.  Williams TM, Haun JE, Friedl WA 1999. The diving physiology of bottle nose dolphins (Tursiops truncatus). J Exp Biol 202:2739-2748.

4.  Williams TM, Friedl WA, Haun JE 1993. The physiology of bottle nose dolphins (Tursiops truncatus). J Exp Biol 179:31-46.