3pAB7. Acoustic measurement of cardiac function on northern elephant seals.

Session: Wednesday Afternoon, December 4

Time: 3:55

Author: William C. Burgess
Location: Monterey Bay Aquarium Res. Inst., Moss Landing, CA 95039
Author: Peter L. Tyack
Location: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543
Author: Burney J. LeBoeuf
Location: Univ. of California at Santa Cruz, Santa Cruz, CA 95064
Author: Daniel P. Costa
Location: Univ. of California at Santa Cruz, Santa Cruz, CA 95064


A self-contained acoustic recording tag has obtained signatures of heartbeat from both captive and free-ranging northern elephant seals (Mirounga angustirostris). Simultaneous electrocardiogram (ECG) and acoustic signatures obtained from the submerged captive seal confirm that seal heartbeat can be monitored acoustically. Recordings from the free-ranging seal demonstrate shallow-water apneic heart rates of 40 to 55 beats per minute, comparable to past observations with ECG tags. Observation of a sixfold increase in beat amplitude at the surface (110 dB re: 1 (mu)Pa) over that at depth (94 dB re: 1 (mu)Pa) may reflect increases in stroke volume at the surface. The findings suggest the feasibility of long-term, reliable, quantitative, and noninvasive cardiac monitoring of a variety of free-ranging marine animals using acoustic logging techniques. [Work supported by MBARI and ONR.]

ASA 132nd meeting - Hawaii, December 1996