Department of Biology and Center for Comparative and Evolutionary Biology of Hearing, University of Maryland, College Park, Maryland 20742, USA.
J Acoust Soc Am. 2012 Jan;131(1):599-607. doi: 10.1121/1.3664082.
Caged fish were exposed to sound from mid-frequency active (MFA) transducers in a 5 × 5 planar array which simulated MFA sounds at received sound pressure levels of 210 dB SPL(re 1 μPa). The exposure sound consisted of a 2 s frequency sweep from 2.8 to 3.8 kHz followed by a 1 s tone at 3.3 kHz. The sound sequence was repeated every 25 s for five repetitions resulting in a cumulative sound exposure level (SEL(cum)) of 220 dB re 1 μPa(2) s. The cumulative exposure level did not affect the hearing sensitivity of rainbow trout, a species whose hearing range is lower than the frequencies in the presented MFA sound. In contrast, one cohort of channel catfish showed a statistically significant temporary threshold shift of 4-6 dB at 2300 Hz, but not at lower tested frequencies, whereas a second cohort showed no change. It is likely that this threshold shift resulted from the frequency spectrum of the MFA sound overlapping with the upper end of the hearing frequency range of the channel catfish. The observed threshold shifts in channel catfish recovered within 24 h. There was no mortality associated with the MFA sound exposure used in this test.
笼养鱼暴露在 5×5 平面阵中的中频主动（MFA）换能器产生的声音中，该换能器模拟的 MFA 声音的接收声压级为 210dB SPL（re 1 μPa）。暴露声音由 2.8 到 3.8 kHz 的 2 秒频率扫描组成，随后是 3.3 kHz 的 1 秒音调。该声音序列每 25 秒重复 5 次，导致累积声暴露水平（SEL（cum））为 220dB re 1 μPa（2）s。累积暴露水平不会影响虹鳟鱼的听力敏感性，虹鳟鱼的听力范围低于所呈现的 MFA 声音的频率。相比之下，一个盲鲷鱼队列在 2300Hz 处显示出统计学上显著的暂时阈值偏移 4-6dB，但在较低的测试频率处没有变化，而第二个队列没有变化。这种阈值偏移很可能是由于 MFA 声音的频谱与盲鲷鱼听力频率范围的上限重叠所致。盲鲷鱼的观察到的阈值偏移在 24 小时内恢复。在本试验中使用的 MFA 声音暴露下没有与死亡率相关。
