The echolocation transmission beam of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis)

While the transmission beam of odontocetes has been described in a number of studies, the majority of them that have measured the transmission beam in two dimensions were focused on captive animals. Within the current study, a dedicated cross hydrophone array with nine elements was used to investiga...

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Bibliographic Details
Published in:The Journal of the Acoustical Society of America
Main Authors: Fang, Liang, Wu, Yuping, Wang, Kexiong, Pine, Matthew K., Wang, Ding, Li, Songhai
Format: Report
Language:English
Published: ACOUSTICAL SOC AMER AMER INST PHYSICS 2017
Subjects:
Acoustics
Audiology & Speech-Language Pathology
FALSE KILLER WHALE
TURSIOPS-TRUNCATUS
PSEUDORCA-CRASSIDENS
PHOCOENA-PHOCOENA
HARBOR PORPOISE
HONG-KONG
CLICKS
PATTERN
SIGNALS
PARAMETERS
Pacific
Killer Whale
Phocoena phocoena
Online Access:http://ir.ihb.ac.cn/handle/342005/31495
https://doi.org/10.1121/1.4996499
Description
Summary:While the transmission beam of odontocetes has been described in a number of studies, the majority of them that have measured the transmission beam in two dimensions were focused on captive animals. Within the current study, a dedicated cross hydrophone array with nine elements was used to investigate the echolocation transmission beam of free-ranging Indo-Pacific humpback dolphins. A total of 265 on-axis clicks were analyzed, from which the apparent peak to peak source levels ranged between 168 to 207 dB (mean 184.5 dB +/- 6.6 dB). The 3-dB beam width along the horizontal and vertical plane was 9.6 degrees and 7.4 degrees, respectively. Measured separately, the directivity index of the horizontal and vertical plane was 12.6 and 13.5 dB, respectively, and the overall directivity index (both planes combined) was 29.5 dB. The beam shape was slightly asymmetrical along the horizontal and vertical axis. Compared to other species, the characteristics of the transmitting beam of Indo-Pacific humpback dolphins were relatively close to the bottlenose dolphin (Tursiops truncatus), likely due to the similarity in the peak frequency and waveform of echolocation clicks and comparable body sizes of the two species. (C) 2017 Author(s).

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