Underwater Noise Level Recordings from a Water Intake Pontoon and Possible Impacts on Yangtze Finless Porpoises in a Natural Reserve

Underwater noise pollution caused by human activities may affect freshwater cetaceans to different degrees. To analyze the impacts of water intake pontoons on Yangtze finless porpoises (Neophocaena asiaeorientalis), this study collected underwater noise data from such a pontoon in a nature reserve, plotted the power spectral density of acoustic signals, and calculated the root mean square sound pressure levels and the magnitude of sound source levels. The 1/3-octave sound pressure level root mean square values at the transient holding pens were