Modern active sonar systems can (almost) continuously transmit and receive sound, which can lead to more masking of important sounds for marine mammals than conventional pulsed sonar systems transmitting at a much lower duty cycle. This study investigated the potential of 1–2 kHz active sonar to mask echolocation-based foraging of sperm whales by modeling their echolocation detection process. Continuous masking for an echolocating sperm whale facing a sonar was predicted for sonar sound pressure levels of 160 dB re 1 μPa², with intermittent masking at levels of 120 dB re 1 μPa², but model predictions strongly depended on the animal orientation, harmonic content of the sonar, click source level, and target strength of the prey. The masking model predicted lower masking potential of buzz clicks compared to regular clicks, even though the energy source level is much lower. For buzz clicks, the lower source level is compensated for by the reduced two-way propagation loss to nearby prey during buzzes. These results help to predict what types of behavioral changes could indicate masking in the wild. Several key knowledge gaps related to masking potential of sonar in echolocating odontocetes were identified that require further investigation to assess the significance of masking.

中文翻译：

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模拟暴露在连续1-2 kHz海军声纳中的回声定位抹香鲸的潜在掩蔽

现代有源声纳系统可以（几乎）连续地发送和接收声音，与以低得多的占空比发送信号的传统脉冲声纳系统相比，它可以导致对海洋哺乳动物重要声音的更多掩盖。这项研究通过对回声定位检测过程进行建模，研究了1–2 kHz有源声纳掩盖基于回声定位的抹香鲸觅食的潜力。鲸面对声纳的echolocating精子连续掩蔽预测为声纳声压级160分贝重新1μPa ²在水平，与间歇屏蔽的120分贝重新1μPa ²，但是模型的预测很大程度上取决于动物的方位，声纳的谐波含量，点击源水平和猎物的目标强度。即使能量源水平低得多，该掩蔽模型预测的嗡嗡声咔嗒声的掩盖潜力也要比常规咔嗒声低。对于蜂鸣声，通过降低蜂鸣声对附近猎物的双向传播损失来补偿较低的源电平。这些结果有助于预测哪些类型的行为变化可能表示野外掩盖。确定了与回声定位牙本质中声纳掩蔽潜能有关的几个关键知识差距，需要进一步研究以评估掩蔽的重要性。