Hong Kong (AsiaNews/Agencies) – In the past three years, 28 white dolphins have been found dead in Hong Kong waters, a report to the Territory’s legislative council (LegCo) said. For Choy So-yuk, a LegCo member with the Democratic Alliance for the Betterment and Progress of Hong Kong, damages to dolphins’ natural habitat are to be blamed for the deaths.
“The carcass of a Chinese white dolphin was found off the Butterfly Beach at Tuen Mun in February this year. As no visible injury was found on the dolphin, it is not ruled out that its death was caused by excessive accumulation of heavy metals in its body,”' Mr Choy said.
In replying to the LegCo member, Hong Kong’s Secretary for the Environment, Transport and Works Sarah Liao Sau-tung said that about 200 Chinese white dolphins lived in waters in and around the territory. Of these, 28 were found dead, including 12 adults, in the past three years, five in 2006, 13 in 2005 and 10 in 2004.
Most of the dolphins live near the Pearl River estuary. Many of those that died “were mainly found in the waters and along the coast of Lantau Island, Tuen Mun, Sha Chau and Lung Kwu Chau,” Ms Liao said. However, she added that most carcasses did not have excessive levels of contamination.
The Territory’s Agricultural Fisheries and Conservation Department in 2005 commissioned the City University of Hong Kong to conduct a two-year study into heavy metals and organic contamination in dolphins. In an earlier study it examined liver tissue samples from 25 Chinese White Dolphins and found that their level of heavy metal contaminants was within norm.
The carcass found in February was so badly decomposed that the cause of death could not be determined, Ms Liao said.
None the less, she informed the council that the territorial government was planning a dolphin conservation programme, which would include monitoring dolphins’ numbers and distribution on a long-term basis, assessing heavy metals and organic contaminants in dolphin carcasses, establishing marine parks to protect them and their habitat, and working with Guangdong authorities to protect dolphins in the Pearl River Estuary.
According to the Hong Kong Dolphin Conservation Society, the territory’s dolphin population has declined considerably in the last decade. Its website speaks of a 40 per cent drop between 1996 and 2005.
For the society's, the main culprit is the dredging work carried out to build Chek Lap Kok Airport. The reclamation project, which led to the airport opening in 1998, caused widespread damage to the marine habitat.
“Reclamation devastates coastal ecology and reduces the amount of fish available to dolphins to feed on,” the society said.
Injuries from ship propellers as well as sea-borne pollution are also a threat.
The World Wide Fund for Nature Hong Kong also blamed dredging related to reclamation work for the dolphins’ predicament, lamenting that “dredging for West Kowloon reclamation resulted in millions of tonnes of toxic mud needing a disposal site.” And “once again,” it said, “an important area for dolphins was chosen to dump the waste.”
The WWF warned that toxic materials can enter the dolphins' food chain, leading to “heavy metals and other pollutants accumulating in their bodies.”
The Chinese White Dolphin is found in coastal waters in many Asian countries, including the Arab states and Malaysia.