A mainland power company has won approval to build a large-scale wind farm in the Pearl River mouth southwest of Lantau.

But the 4.2 billion yuan (HK$4.98b) scheme by a China Southern Power Grid subsidiary has prompted fears  that it will pose yet another threat to the endangered Chinese White Dolphin.

The 120MW wind farm is to be built on Sanjiao Mountain Island in the centre of the Pearl River, about 8 km southwest of Fan Lau.

The Guangdong Dept of Oceans and Fisheries announced its approval for the project last November, declaring the project environmentally “feasible,” local news site The Stand News reported.

The Hong Kong Dolphin Conservation Society said the wind generators would be just 2.5km from regular dolphin haunts. It points out that the construction would involve percussive piling and on completion the turbines would operate 24 hours a day. The result will be significant noise on the sea bottom and a “serious impact on highly noise-sensitive dolphins.”

The Chinese White Dolphin population has shrunk by more than half in the past decade as a result of reclamation and construction work for the Hong Kong-Macau bridge and the airport third runway and higher sea traffic volumes. It is listed as a near-threatened species under the 2010 IUCN red list and as a species threatened with extinction under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

Meanwhile, the Marine Department has set up two temporary acoustic monitoring stations along the path of the Chek Lap Kok-Tuen Mun Link, now under construction. The stations, at Siu Ho Wan on north Lantau and Lung Kwu Tun, Tuen Mun, will collect data on dolphin vocalisations.