[MARMAM] New publication on Heaviside's dolphin acoustics

Tadamichi Morisaka chaka at wrc.kyoto-u.ac.jp
Sun Feb 6 18:24:34 PST 2011

Dear Marmam subscribers,

The following paper has recently been published online in the Journal
of the Acoustical Society of America.
For a copy, you can check the journal website at
http://link.aip.org/link/?JAS/129/449, or contact:
chaka at wrc.kyoto-u.ac.jp .

Echolocation signals of Heaviside's dolphins (Cephalorhynchus heavisidii)
Tadamichi Morisaka, Leszek Karczmarski, Tomonari Akamatsu, Mai Sakai,
Steve Dawson, Meredith Thornton, J. Acoust. Soc. Am. 129, 449-457

The abstract is as follows;

Field recordings of echolocation signals produced by Heaviside's
dolphins (Cephalorhynchus heavisidii) were made off the coast of South
Africa using a hydrophone array system. The system consisted of three
hydrophones and an A-tag (miniature stereo acoustic data-logger). The
mean centroid frequency was 125 kHz, with a -3 dB bandwidth of 15 kHz
and -10 dB duration of 74 µs. The mean back-calculated apparent source
level was 173 dB re 1 µPap.-p.. These characteristics are very similar
to those found in other Cephalorhynchus species, and such narrow-band
high-frequency echolocation clicks appear to be a defining
characteristic of the Cephalorhynchus genus. Click bursts with very
short inter-click intervals (up to 2 ms) were also recorded, which
produced the "cry" sound reported in other Cephalorhynchus species.
Since inter-click intervals correlated positively to click duration
and negatively to bandwidth, Heaviside's dolphins may adjust their
click duration and bandwidth based on detection range. The bimodal
distribution of the peak frequency and stable bimodal peaks in spectra
of individual click suggest a slight asymmetry in the click production

URL: http://link.aip.org/link/?JAS/129/449
DOI: 10.1121/1.3519401
Permalink:      http://dx.doi.org/10.1121/1.3519401


Tadamichi MORISAKA, Ph.D.

Assistant Professor
Wildlife Research Center of Kyoto University

3F, 2-24, Tanaka-Sekiden-cho, Sakyo-ku,
Kyoto 606-8203, Japan

Tel: 075-771-4388; Fax: 075-771-4394
chaka at wrc.kyoto-u.ac.jp

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