Clear Water before disturbance © Alan Leung

Site visit in Tung Chung Stream, Aug 2006 © Alan Leung

WWF has grave concerns following the apparent loss of aquatic life, including fish and insects, in the Tung Chung stream on Lantau. Our site inspection near Shek Mum Kap at the midstream section of the Tung Chung stream on 14 August 2006 revealed significant sediment runoff from upstream water. Virtually no fish and insects were observed in the stream. Tung Chung stream has been identified as one of Hong Kong’s most ecologically important streams which supports more than 20 indigenous species of freshwater fish as well as many species of conservation importance.

The water quality of the stream used to be excellent and crystal clear. In 2003, a 330-metre section of Tung Chung Stream was damaged by illegal excavation work by a sub-contractor supplying boulders to Disneyland. After months of intense restoration effort the stream was back to life. However, the current threats facing by the stream may be even worst than the excavation incident.

Freshwater fish - Acrossocheilus beijiangensis © Alan Leung

During a thirty-minute inspection over a 30-metre stream section, only a small number of aquatic insect larvae and no fish were found in the stream. Species observed during our visits in the same section last year, including the rare fish Beijiang Thick-lipped Barb Acrossocheilus beijiangensis and the common Predaceous Chub Parazacco spilurus, had disappeared. It was suspected that the impacts may extend more than two kilometres along the stream.

Increase in runoff in the stream not only will cause a direct impact to the stream biotic communities, it may also affect the water quality in Tung Chung Bay. An ecologically sensitive area, the seagrass bed in San Tau, is only a kilometre away from the river mouth of the Tung Chung Stream.