Title page for etd-0619113-124907


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URN etd-0619113-124907
Author Jian-ming Liu
Author's Email Address No Public.
Statistics This thesis had been viewed 5537 times. Download 523 times.
Department IAMPUT
Year 2013
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Passive Acoustic Study on the Distribution of Chinese White Dolphins, Sousa chinensis, and Ambient noise
Date of Defense 2013-06-13
Page Count 86
Keyword
  • Offshore Distance
  • Ambient Noise
  • Whistle
  • Depth
  • Chinese White Dolphin
  • Abstract Cetaceans is a kind of marine mammals that lives by sound, which uses high-frequency echolocation click to probe the environment, as well as uses low-frequency whistle to identify different individuals for social activities. However cetacean surveys are often limited by climate and depth of the coastal water , in order to compensate for the shortage of visual observation, this study used sonobuoy acoustic system to measure the whistle of Chinese White Dolphins, to observe its appearance in time and spatial distribution, and analyze the local ocean ambient noise. Three experiments were conducted at southern end of river mouth of Tadu River in July-August 2010, sonobuoys were deployed at different depth and distance from shore. Statistics of recorded whistles show 40% of appearance every hour, the main appearance time of white dolphins were 06:00~12:00 and 16:00~24:00. The activity range of white dolphins is 13m of depth (most frequently at 5m) and within 4.4km offshore. The foraging behavior of white dolphins was inferred by means of this activity model. In terms of tidal variance, white dolphins had different preferences for tidal activities according to the distances from shore observed from the three experiments, but their whistles centered from ebb to dry tide. For the ambient noise analysis of the habitat of white dolphins, the nighttime ambient noise was noisier than the daytime, which was probably caused by frequent night fishing and fish sounds. In addition, the far-shore ambient noise was noisier than the near-shore since most of fishing operations were far away from shore. Furthermore, it was found in the ship noise experiment conducted in the Kaohsiung Harbor that the noise generated by out board boats tended to shadow the whistles of white dolphins, approximately at 3-6 kHz, more likely than the noise generated by fishing boats. Nevertheless, the influence of noise on the activities of Chinese white dolphins is still uncertain so far. It was proved in this study that underwater acoustical measurements can be employed to establish references for future long-term research on Chinese white dolphin.
    Advisory Committee
  • Hin-Kiu Mok - chair
  • Linus Y.S Chiu - co-chair
  • Ruey-Chang Wei - advisor
  • Files
  • etd-0619113-124907.pdf
  • Indicate in-campus at 5 year and off-campus access at 5 year.
    Date of Submission 2013-08-26

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