Sperm whale sound production - The Journal of Experimental ...

1902
P. T. Madsen and others
Depth (m)
0
–200
–400
–600
–800
0
0 500 1000 1500 2000
Click number
Fig. 4. Inter-click interval (open circles) and dive depth as a function
of click number during each of the 1804 usual clicks produced
during the dive profiled in Fig. 3.
re. 1 µPa (peak to peak, pp), and the amplitudes of the
following clicks increase to approximately 178 dB re. 1 µPa
(pp). The acoustic output is independent of depth within a
20 dB range from 170 to 190 dB re. 1 µPa (pp) (Fig. 5).
As seen from the data presented in Table 1, there are marked
differences between the waveforms of usual clicks and coda
clicks. The coda clicks (N=54) have a mean recorded level of
165±5 dB re. 1 µPa (pp), which is significantly lower than
the mean recorded level of usual clicks (N=1804) of
178±4 dB re. 1 µPa (pp) (P