High-Speed Vessel Noises in West Hong Kong Waters and Their Contributions Relative to Indo-Pacific Humpback Dolphins (Sousa chinensis)
Figure 4
The various sound pressure level contributions of a high-speed ferry (R66; a), at West Lantau number 3 with a Beaufort sea state of 2. The orange line indicates the ambient sounds of Southwest Lantau number 2, located between the Soko Islands with very little boat traffic and no vessels present during recording. The red line indicates South Lantau Vessel Fairway, a busy traffic area, especially for ferries. South Lantau Vessel Fairway was recorded with several ferries and a shrimp trawler present. (b) shows selected sound spectra of the above high-speed ferry in comparison to the spectra of humpback dolphin communication sounds at a distance of ≤100 m. (c) The various sound pressure level contributions of a high-speed ferry (R92), at Northwest Lantau number 5 with a Beaufort sea state of 4. The ambient noise level (represented in purple) was taken from Northwest Lantau number 1, an area with very little boat traffic, located within the Sha Chau and Lung Kwu Chau Marine Park. The red line is the same as that in (a). Sound spectra are represented below (d) for the high-speed ferry, including the same humpback dolphin spectra as (b).
