Kastelein Ronald A, Helder-Hoek Lean, Cornelisse Suzanne A, Defillet Linde N, Huijser Léonie A E, Terhune John M
Sea Mammal Research Company (SEAMARCO), Julianalaan 46, 3843 CC Harderwijk, the Netherlands.
Cetacean Ecology and Acoustics Laboratory (CEAL), University of Queensland, 37 Fraser Street, Dunwich, Queensland 4183, Australia.
J Acoust Soc Am. 2020 Dec;148(6):3873. doi: 10.1121/10.0002781.
This study concludes a larger project on the frequency-dependent susceptibility to noise-induced temporary hearing threshold shift (TTS) in harbor seals (Phoca vitulina). Here, two seals were exposed to one-sixth-octave noise bands (NBs) centered at 0.5, 1, and 2 kHz at several sound exposure levels (SELs, in dB re 1 μPas). TTSs were quantified at the center frequency of each NB, half an octave above, and one octave above, at the earliest within 1-4 min after exposure. Generally, elicited TTSs were low, and the highest TTS occurred at half an octave above the center frequency of the fatiguing sound: after exposure to the 0.5-kHz NB at 210 dB SEL, the TTS at 0.71 kHz was 2.3 dB; after exposure to the 1-kHz NB at 207 dB SEL, the TTS at 1.4 kHz was 6.1 dB; and after exposure to the 2-kHz NB at 215 dB SEL, TTS at 2.8 kHz was 7.9 dB. Hearing always recovered within 60 min, and susceptibility to TTS was similar in both seals. The results show that, for the studied frequency range, the lower the center frequency of the fatiguing sound, the higher the SEL required to cause the same TTS.
本研究是一个关于港海豹（Phoca vitulina）对噪声诱发的暂时性听阈偏移（TTS）频率依赖性易感性的更大项目的一部分。在此，两只海豹在几个声暴露水平（SEL，以dB re 1 μPa为单位）下，暴露于以0.5、1和2 kHz为中心的1/6倍频程噪声带（NB）中。在暴露后最早1至4分钟内，在每个NB的中心频率、中心频率上方半个倍频程以及一个倍频程处对TTS进行量化。一般来说，诱发的TTS较低，最高的TTS出现在疲劳声音中心频率上方半个倍频程处：在210 dB SEL下暴露于0.5 kHz的NB后，0.71 kHz处的TTS为2.3 dB；在207 dB SEL下暴露于1 kHz的NB后，1.4 kHz处的TTS为6.1 dB；在215 dB SEL下暴露于2 kHz的NB后，2.8 kHz处的TTS为7.9 dB。听力总是在60分钟内恢复，并且两只海豹对TTS的易感性相似。结果表明，在所研究的频率范围内，疲劳声音的中心频率越低，引起相同TTS所需的SEL越高。
