Fewer ferries lead to more Chinese white dolphin activity, Hong Kong group finds
- Wildlife group calls on government to divert cross-border ferry operations in the Southern Lantau Fairway
- Noise produced by high-speed vessels interferes with dolphins feeding habits, says project manager
Chinese white dolphins were found to be significantly more active in southern Hong Kong waters after the frequency of cross-border ferry services was reduced during the Covid-19 pandemic, according to a green group’s study.
The findings have prompted WWF-Hong Kong to call on the government to divert cross-border ferry operations in the Southern Lantau Fairway.
The group said on Thursday that the acoustic and visual data they collected in the area between February 2020 to January 2021 showed a 50 per cent increase in the activities of Chinese white dolphins.
During the period when Hong Kong-Macau ferry services were suspended because of the pandemic, an average of 32.4 seconds per hour of dolphin occurrence and activities were recorded in a day, in comparison to the 21.6 seconds recorded between January 2019 to February 2020 when the vessels were in operation.
The green group has been using passive acoustic monitoring stations to record dolphin occurrences since 2016. These stations operate 24 hours a day, and they record underwater noises from ferries, as well as the echoes from dolphins to indicate their activities.
Six stations were set up at Kai Yat Kok, Fan Lau, Tai A Chau, Tau Lo Chau and Mong Tong Wan, areas where Chinese white dolphins and finless porpoises can be found.
Chinese white dolphins were more relaxed and sociable with reduced underwater noise disturbances, according to the group’s boat-based visual survey conducted from May 2020 to April 2021.
