Study On The Impact Of Underwater Pile-driving Noise On Rare Marine Mammals(Chinese White Dolphin And Spotted Seal)in China Sea

Along with the construction and development of human society, the industry has given a new focus on exploring ocean resources. But accompany with the construction activities, the underwater noise pollution will seriously disturb the living creatures in the sea, including marine mammals. Like bridges, offshore wind farms, harbor piers, oil and gas platforms, etc., the underwater pile-driving is a necessary stage, and also is the noisiest stage among these projects.Chinese white dolphin and spotted seal are national protected marine mammal species in China; and both have stable habitats in China Sea. Underwater auditory and vocalization are their unique abilities living in turbid shallow sea, helping them to be sensitive to environment, avoid prey, foraging, making communication with each other. Besides, like other cetaceans, Chinese white dolphin also use echolocation clicks to navigate.Foreign researches and reports showed that underwater pile-driving noise could seriously injure the hearing system of marine mammals; meanwhile it also could mask the vocalization signals. The animals which disturbed by these noises could be lead to threshold shift, or have to abandon their original active areas or habitats.In order to protect spotted seals and Chinese white dolphins from the effects of the underwater pile-driving noise, it’s necessary to monitor the construction process and give assessments to the project. By analyzing the preferences and characteristics of underwater pile-driving noise, give an assessment to the pile-driving noise source level and propagation effecting area; combining with the analysis of hearing and vocal sound signals of spotted seal and Chinese white dolphin, study and discuss the impact of the animals received from the noise, so as to give preliminary suggestions to the noise control and sound protection of these marine mammals.The man contents of this paper include:1) Simple introduction of research frontiers about underwater pile-driving noise and bio-sonar of cetacean and pinipped, including hearing threshold and vocalizations, and local and foreign protection status and act. 2) Preliminary discussed the system components meets the require of underwater pile-driving noise monitoring, described the parameters which should be report for noise description, and their calculation method, by using MATLAB programing.3) Conducted a preliminary comparison of different methods in underwater pile-driving noise source level assessment by calculating field monitoring data.4) Sea fieldwork monitoring and sound-recording of wild Chinese white dolphins and spotted seals, conducted waveform and spectral analysis of the data sample based on MATLAB and Adobe Audition.5) Compare the underwater pile-driving noise to hearing thresholds and vocalizations of both animals, discussed about the impacts and harms of the noise to them, give some suggestion on their acoustic protection.