title: The effects of high-intensity, low-frequency active sonar on rainbow trout.
abstract: 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 microPa(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.
authors.affiliation: Department of Biology and Center for Comparative and Evolutionary Biology of Hearing, University of Maryland, College Park, Maryland 20742, USA. apopper@umd.edu
authors.forename: Arthur N
authors.initials: AN
authors.lastname: Popper
authors.forename: Michele B
authors.initials: MB
authors.lastname: Halvorsen
authors.forename: Andrew
authors.initials: A
authors.lastname: Kane
authors.forename: Diane L
authors.initials: DL
authors.lastname: Miller
authors.forename: Michael E
authors.initials: ME
authors.lastname: Smith
authors.forename: Jiakun
authors.initials: J
authors.lastname: Song
authors.forename: Peter
authors.initials: P
authors.lastname: Stein
authors.forename: Lidia E
authors.initials: LE
authors.lastname: Wysocki
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001309:Auditory Threshold; D007758:Ear, Inner / Q000648:ultrastructure; D016057:Evoked Potentials, Auditory, Brain Stem; D006317:Hearing Loss, Noise-Induced / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D008855:Microscopy, Electron, Scanning; D017686:Oncorhynchus mykiss; D011312:Pressure; D013018:Sound Spectrography; D014465:Ultrasonics / Q000009:adverse effects*