Underwater noise levels in Indian waters off the coast of Mormugao Port

Figures & data

Figure 1. Mormugao port general view on Indian map.

Figure 2. Hydrophone deployment location and Mormugao port ship traffic lane. Map obtained from Marine traffic.com website.

Table 1. Hydrophone specifications.

Make	Keltron
Model	KE10
Sampling frequency	25 kHz
Data duration	30 sec
Receiving sensitivity	−162 dB

Table 2. Data collected period.

Deployment location	Start date	End date	No. of days
Goa	17 May 2012	31 May 2012	15 days
Goa	04 June 2012	27 June 2012	24 days

Table 3. Meteorological data.

Dataset (Mean value)	May 2012	June 2012
Wind speed	7 m/s	7.5 m/s
Zonal wind speed	4.2 m/s	5.2 m/s
Sea Surf Temp	28.3 degc	27.9 degc
Sea level pressure	1008.40 mb	1007.40 mb
Salinity 5, 15 and 25 m depths	35.42 psu 35.42 psu 35.46 psu	35.30 psu 35.30 psu 35.38 psu
i current 5, 15 and 25 m depths (x-direction)	0.0165 m/s −0.0070 m/s −0.015 m/s	0.0161 m/s −0.0130 m/s −0.035 m/s
j current 5, 15 and 25 m depths (y-direction)	−0.0303 m/s −0.021 m/s 0.004 m/s	−0.0307 m/s −0.026 m/s −0.0045 m/s

Figure 3. Ocean noise levels spectrum indicating peak noise levels at 6.7 kHz.

Figure 4. The peak sound pressure levels (SPL) histograms indicating the noise levels occurrences in a month (A) May (B) June.

Figure 5. Comparison of ship noise and ambient noise spectrums in the frequency range up to 6 kHz.

Figure 6. Ship noise 1/12 octave frequency spectrum from a dataset with 30-sec duration in a day.

Figure 7. Low-frequency day-wise shipping noise levels (A) May (B) June.

Figure 8. Range of sound levels of ship datasets for both May and June months.

Figure 9. The Fish noise spectrogram indicating the disturbances in (A) High frequency (B) low frequency.

Figure 10 . The Ocean noise spectrogram indicating the ambient and ship passage disturbance (A) Ambient on 19 May 2012 at 10:00 AM (B) Ship disturbance 19 May 2012 at 4:00 AM.

Figure 11. The time series representation of ocean noise levels for the 30-sec duration (C) Ambient 19th May 2012 at 10:00 AM (D). Ship disturbance 19 May 2012 at 4:00 AM.