Behavioral Impacts of a 69 kHz Acoustic Transmitter on Aquarium-Housed Harbor Seals (Phoca vitulina) and Harp Seals (Pagophilus groenlandicus)
Abstract
Acoustic telemetry is extensively used for studies of habitat use and survival of wild aquatic animals. The most frequently used acoustic transmitters, which are either externally attached or surgically implanted into animals, produce a short succession of acoustic “pings” at 69 kHz at a predetermined interval and between 137–158 dB, which can then be detected on acoustic hydrophones deployed in their environment.1,2 This informative technology, initially developed for fishes, is generating interest to address important knowledge gaps in wild pinniped populations. Since the emitted sound frequency is at the threshold of the hearing capacity of seals,3 questions regarding the welfare impact of these transmitters arise. The objective of this study was to determine if and how the sound produced by these transmitters would influence the behavior of seals in a controlled environment. The impact of the presence of an underwater acoustic transmittera on the behavior of four aquarium-housed harbor seals and three harp seals was assessed. Preset animal welfare endpoints were reached on the second day of exposure to the transmitter, prematurely terminating the study. Reluctance to get in the water, decreased appetite, and agitation were observed. Despite the study’s early interruption, it was obvious that the seals could hear the sound produced by the transmitter and appeared negatively affected. It remains unclear how these findings in geriatric animals in a controlled environment might translate to wild phocids. Furthermore, longer-duration studies are needed to determine if habituation may occur but may be difficult to achieve in a controlled environment without compromising animal welfare.
Endnotes
a. V13 acoustic transmitter, InnovaSea Systems Inc., Halifax, NS, Canada
Acknowledgements
The authors wish to thank the team of trainers for their collaboration with this project.
*Presenting author
+Student presenter
Literature Cited
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