WWF-Hong Kong has called for the government to reduce the impact of high-speed ferries on the endangered dolphin population off South Lantau.

It says the AFCD should consider rerouting ferries away from dolphin habitats or set up a speed restriction zone in the South Lantau waters as part of a holistic plan to reduce the effect of marine traffic.

The conservation group has just completed a 12-month underwater sound survey off southwest Lantau that found Chinese white dolphins and finless porpoises have altered their foraging patterns to avoid marine vessels.

Just 47 dolphins remain in Hong Kong waters, a result of continuous construction on the north side of Lantau and the heavy traffic on the southern side.

Dozens of ferries between Hong Kong and Macau pass through the channel between South Lantau, Cheung Chau and the Soko Islands every day, impacting on dolphins directly and on their food sources.

“Fast moving boats and ferries can inhibit their ability to locate food and increase stress levels,” said Dr Matthew Pine, a marine scientist and underwater noise specialist.

He says the survey found fewer dolphins were detected off Fan Lau between 3am-7am, suggesting they were being limited in their movement during the heavily-trafficked periods during the day.

They were using the quiet period in the early morning to cross to the Soko Islands, a key foraging habitat. Pine added:

“Ship strikes are a great risk for the mammals since we see them travelling across the ferry channel to forage around the Soko Islands, including at night when there’s no chance of ferries seeing them. Chronic exposure to high noise levels from vessels can cause desensitisation to vessel presence and inhibit communication between the animals, which may be a factor in a potential strike.”

Samantha Lee, WWF-Hong Kong’s conservation manager for oceans, says the AFCD, the marine sector and experts needed to work together to identify measures that would lower the impact of ferries on dolphins and safeguard their habitats.

“The Agriculture, Fisheries and Conservation Department must develop a holistic fisheries management and enforcement plan to facilitate the recovery of fisheries resources for the dolphins to prey on inside the marine park. With more to eat and a haven away from high-speed vessels, the Chinese white dolphin population can begin to recover.”

The government has proposed combining two marine parks off South Lantau to create the territory’s largest marine sanctuary as an offset to the arrival of the Shek Kwu Chau incinerator, which will add further to marine traffic density in South Lantau waters.

WWF is holding a public seminar at HKPC Building, Kowloong Tong, 11am today.