Mid- to high-frequency noise from high-speed boats and its potential impacts on humpback dolphins.
The impact of noise made by vessels on marine animals has come under increased concern. However, most measurements on noise from vessels have only taken into account the low-frequency components. For cetaceans operating in the mid- and high-frequencies, such as the Indo-Pacific humpback dolphin (Sousa chinensis), mid- to high-frequency noise components may be of more concern, in terms of their potential impacts. In this study, noise made by a small high-speed boat was recorded using a broadband recording system in a dolphin watching area focusing on the effects on humpback dolphins in Sanniang Bay, China. The high-speed boat produced substantial mid- to high-frequency noise components with frequencies to >100 kHz, measured at three speeds: ∼40, 30, and 15 km/h. The noise from the boat raised the ambient noise levels from ∼5 to 47 decibels (dB) root-mean-square (rms) across frequency bands ranging from 1 to 125 kHz at a distance of 20 to 85 m, with louder levels recorded at higher speeds and at closer distances. To conclude, the noise produced by the small high-speed boat could be heard by Sousa chinensis and therefore potentially had adverse effects on the dolphins.
Sanya Key Laboratory of Marine Mammal and Marine Bioacoustics, Sanya Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China.
Songhai
S
Li
Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Department of Marine Science, College of Ocean, Qinzhou University, Guangxi 535099, China.
Haiping
H
Wu
Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Department of Marine Science, College of Ocean, Qinzhou University, Guangxi 535099, China.
Youhou
Y
Xu
Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Department of Marine Science, College of Ocean, Qinzhou University, Guangxi 535099, China.
Chongwei
C
Peng
Sanya Key Laboratory of Marine Mammal and Marine Bioacoustics, Sanya Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China.
Liang
L
Fang
Sanya Key Laboratory of Marine Mammal and Marine Bioacoustics, Sanya Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China.
Mingli
M
Lin
Sanya Key Laboratory of Marine Mammal and Marine Bioacoustics, Sanya Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China.
Luru
L
Xing
Sanya Key Laboratory of Marine Mammal and Marine Bioacoustics, Sanya Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China.
Peijun
P
Zhang
D000819:Animal Communication; D000818:Animals; D001309:Auditory Threshold; D061006:Bays; D002681:China; D004289:Dolphins / Q000502:physiology*; D056727:Endangered Species; D006802:Human Activities; D009622:Noise / Q000009:adverse effects*; D009624:Noise, Transportation / Q000009:adverse effects*; D010470:Perceptual Masking; D012767:Ships; D013016:Sound; D013018:Sound Spectrography