The effects of high-intensity, low-frequency active sonar on rainbow trout

• Published in: The Journal of the Acoustical Society of America Vol. 122; no. 1; pp. 623 - 635
• Main Authors: Popper, Arthur N., Halvorsen, Michele B., Kane, Andrew, Miller, Diane L., Smith, Michael E., Song, Jiakun, Stein, Peter, Wysocki, Lidia E.
• Format: Journal Article
• Language: English
• Published: Woodbury, NY Acoustical Society of America 01-07-2007; American Institute of Physics
• Subjects: Acoustic Stimulation; Acoustics; Animals; Auditory Threshold; Ear, Inner - ultrastructure; Evoked Potentials, Auditory, Brain Stem; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Hearing Loss, Noise-Induced - etiology; Hearing Loss, Noise-Induced - pathology; Hearing Loss, Noise-Induced - physiopathology; Microscopy, Electron, Scanning; Oncorhynchus mykiss; Physics; Pressure; Sound Spectrography; Ultrasonics - adverse effects; High frequency
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.2735115

This study investigated the effects on rainbow trout (
Oncorhynchus mykiss
) of exposure to high-intensity, low-frequency sonar using an element of the standard Surveillance Towed Array Sensor System Low Frequency Active (LFA) sonar source array. Effects of the LFA sonar on hearing were tested using auditory brainstem responses. Effects were also examined on inner ear morphology using scanning electron microscopy and on nonauditory tissues using general pathology and histopathology. Animals were exposed to a maximum received rms sound pressure level of
193
dB
re
1
μ
Pa
2
for 324 or
648
s
, an exposure that is far in excess of any exposure a fish would normally encounter in the wild. The most significant effect was a
20
-
dB
auditory threshold shift at
400
Hz
. However, the results varied with different groups of trout, suggesting developmental and/or genetic impacts on how sound exposure affects hearing. There was no fish mortality during or after exposure. Sensory tissue of the inner ears did not show morphological damage even several days post-sound exposure. Similarly, gross- and histopathology observations demonstrated no effects on nonauditory tissues.