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Sonar gain control in echolocating finless porpoises (Neophocaena phocaenoides) in an open water
Songhai Li1, Ding Wang, Kexiong Wang
1Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, 430072, People's Republic of China.
Abstract:
Source levels of echolocating free-ranging Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) were calculated using a range estimated by measuring the time delays of the signals via the surface and bottom reflection paths to the hydrophone, relative to the direct signal. Peak-to-peak source levels for finless porpoise were from 163.7 to 185.6 dB re: 1 microPa. The source levels are highly range, dependent and varied approximately as a function of the one-way transmission loss for signals traveling from the animals to the hydrophone.
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