Temporary hearing threshold shift in harbor seals (Phoca vitulina) due to a one-sixth-octave noise band centered at 16 kHz
Abstract
Temporary hearing threshold shifts (TTSs) were investigated in two adult female harbor seals after exposure for 60 min to a continuous one-sixth-octave noise band centered at 16 kHz (the fatiguing sound) at sound pressure levels of 128–149 dB re 1 μPa, resulting in sound exposure levels (SELs) of 164–185 dB re 1 μPa2s. TTSs were quantified at the center frequency of the fatiguing sound (16 kHz) and at half an octave above that frequency (22.4 kHz) by means of a psychoacoustic hearing test method. Susceptibility to TTS was similar in both animals when measured 8–12 and 12–16 min after cessation of the fatiguing sound. TTS increased with increasing SEL at both frequencies, but above an SEL of 174 dB re 1 μPa2s, TTS was greater at 22.4 kHz than at 16 kHz for the same SELs. Recovery was rapid: the greatest TTS, measured at 22.4 kHz 1–4 min after cessation of the sound, was 17 dB, but dropped to 3 dB in 1 h, and hearing recovered fully within 2 h. The affected hearing frequency should be considered when estimating ecological impacts of anthropogenic sound on seals. Between 2.5 and 16 kHz the species appears equally susceptible to TTS.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 01, 2019
- Source ID
- 10.1121/1.5130385
Entities
People
- John M. Terhune
- Lean Helder-hoek
- Léonie A. E. Huijser
- Ronald A. Kastelein
- Suzanne Cornelisse
Organizations
- United States Navy
- University of New Brunswick
- University of Queensland