Marine Mammal Research, Department of Ecoscience, Aarhus University, Aarhus, Denmark.
Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Odense, Denmark.
Sci Rep. 2024 Feb 29;14(1):4988. doi: 10.1038/s41598-024-55481-z.
Seal scarers (or acoustic harassment devices, AHDs) are designed to deter seals from fishing gear and aquaculture operations, as well as to prevent seals from entering rivers to avoid predation on valuable fish. Our study investigated the potential effects of AHDs on non-target species, specifically the Eurasian otters (Lutra lutra), by testing the reaction of two rehabilitated otters to simulated AHDs sounds at 1 and 14 kHz, with a received sound intensity of 105-145 dB re 1 µPa rms. The 1 kHz sounds were used to investigate alternative frequencies for scaring seals without scaring otters. The otters reacted to both 1 and 14 kHz tonal signals when retrieving fish from a feeding station 0.8 m below the surface. Their diving behaviour and time to extract food progressively increased as sound intensity increased for all tested sound levels. Notably, the sound levels used in our tests were significantly lower (40-80 dB) than the source levels from commercial AHDs. These findings highlight the importance of caution when using AHDs in river and sea habitats inhabited by otters, as AHDs can change their behaviour and potentially result in habitat exclusion.
驱鲨器（或声学骚扰装置，AHDs）旨在阻止海豹靠近渔具和水产养殖作业，防止海豹进入河流以避免捕食有价值的鱼类。我们的研究通过测试两只康复水獭对 1 和 14 kHz 模拟 AHD 声音的反应，来调查 AHD 对非目标物种（欧亚水獭（Lutra lutra））的潜在影响，模拟声音的接收声强为 105-145 dB re 1 µPa rms。1 kHz 的声音用于研究在不惊吓水獭的情况下驱赶海豹的替代频率。当水獭从离水面 0.8 米的投喂站取回鱼时，它们对 1 和 14 kHz 音调信号做出了反应。随着测试的所有声级的声强增加，它们的潜水行为和取出食物的时间逐渐增加。值得注意的是，我们测试中使用的声级（40-80 dB）明显低于商业 AHD 发出的声源级。这些发现强调了在水獭栖息的河流和海洋栖息地使用 AHD 时要谨慎，因为 AHD 可能会改变它们的行为，并可能导致栖息地排斥。
