Fig. 1 Experimental site of the south-western part of Jeju Island (33°15'8.58"N, 126°11'35.94"E).
Fig. 2. Spectrogram of signal recorded in the south-western part of Jeju Island on 14 June 2017, (a) full data, (b) whistle signals (FFT size : 1024, overlap size : 512, frequency resolution : 375 Hz, window : hanning).
Fig. 3. Comparison of power spectral density between echolocation click signal of Indo-Pacific bottlenose dolphin (solid line) and ambient noise (dotted line) (a) spectrogram, (b) power spectral density (FFT size: 1024, frequency resolution: 375 Hz, window: hanning).
Fig. 4. Waveforms and energy spectral densities of 8 types of echolocation clicks emitted by Indo-Pacific bottlenose dolphin and acoustic parameters [signal duration (ΔT), 1st peak frequency (Fp1), 2nd peak frequency (Fp2), 3 dB bandwidth (ΔF3dB), 10 dB bandwidth (ΔF10dB)], (a) - (d) click signals with 1st peak frequency of ~ 100 kHz,(e) - (h) click signals with 1st peak frequency of ~ 60 kHz.
Fig. 5. Distribution of acoustic parameters of echolocation clicks emitted by Indo-Pacific bottlenose dolphin (N = 1597) (a) signal duration (ΔT), (b) 1st peak frequency (Fp1), (c) 2nd peak frequency (Fp2), (d) 3 dB bandwidth (ΔF3dB) , (e) 10 dB bandwidth (ΔF10dB).
Fig. 6. Scatter plots of (a) signal duration (ΔT) versus 1st peak frequency (Fp1), (b) 3 dB bandwidth (F3dB) versus 1st peak frequency (Fp1), and (c) 3 dB bandwidth (ΔF3dB) versus signal duration (ΔT).
Fig. 7. Scatter plots of (a) signal duration (ΔT) versus 1st peak frequency (Fp1) [Fp1 < 75 kHz], (b) 3 dB bandwidth (ΔF3dB) versus 1st peak frequency (Fp1) [Fp1 < 75 kHz], (c) signal duration (ΔT) versus 1st peak frequency (Fp1) [Fp1 > 75 kHz], and (d) 3 dB bandwidth (ΔF3dB) versus 1st peak frequency (Fp1) [Fp1 > 75 kHz]. The equation of the least square linear regression line through the data, its correlation coefficient are indicated in the upper of each plot.
Table 1. Comparisons of acoustic parameters of echolocation clicks emitted by Indo-Pacific bottlenose dolphin by habitat (Jeju Island of South Korea and Exmouth Gulf North West Cape of Australia).
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