TY - JOUR
TI - Temporary Shift in Masked Hearing Thresholds in a Harbor Porpoise (Phocoena phocoena) after Exposure to Seismic Airgun Stimuli
AU - Lucke, K
AU - Siebert, U
AU - Lepper, P
AU - Blanchet, M
T2 - Journal of the Acoustical Society of America
AB - An auditory study was conducted to derive data on temporary threshold shift (TTS) induced by single impulses. This information should serve as basis for the definition of noise exposure criteria for harbor porpoises. The measurements of TTS were conducted on a harbor porpoise by measuring the auditory evoked potentials in response to amplitude-modulated sounds. After obtaining baseline hearing data the animal was exposed to single airgun stimuli at increasing received levels. Immediately after each exposure the animal's hearing threshold was tested for significant changes. The received levels of the airgun impulses were increased until TTS was reached. At 4 kHz the predefined TTS criterion was exceeded at a received sound pressure level of 199.7 dB(pk-pk) re 1 mu Pa and a sound exposure level (SEL) of 164.3 dB re 1 mu Pa(2)s. The animal consistently showed aversive behavioral reactions at received sound pressure levels above 174 dB(pk-pk) re 1 mu Pa or a SEL of 145 dB re 1 mu Pa(2)s. Elevated levels of baseline hearing sensitivity indicate potentially masked acoustic thresholds. Therefore, the resulting TTS levels should be considered masked temporary threshold shift (MTTS) levels. The MTTS levels are lower than for any other cetacean species tested so far.
DA - 2009/06//
PY - 2009
VL - 125
SP - 4060
EP - 4070
UR - http://scitation.aip.org/content/asa/journal/jasa/125/6/10.1121/1.3117443
DO - 10.1121/1.3117443
LA - English
KW - Noise
KW - Marine Mammals
KW - Cetaceans
ER -