Contaminated White Dolphin carcasses being found in HK waters: lawmaker

PUBLISHED : Wednesday, 18 April, 2007, 12:00am
UPDATED : Wednesday, 18 April, 2007, 12:00am

Twenty-eight Chinese White Dolphins have been found dead in Hong Kong waters since 2004, new statistics released in the Legislative Council on Wednesday showed.

Legislator Choy So-yuk, of the Democratic Alliance for the Betterment and Progress of Hong Kong, told Legco he was concerned about dolphins dying because of damage to their natural habitat.

'It has been reported that 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, hence it is not ruled out that its death was caused by excessive accumulation of heavy metals in its body,'' Mr Choy said.

He asked the government for statistics of dolphin numbers and deaths in Hong Kong waters.

Secretary for the Environment, Transport and Works Sarah Liao Sau-tung replied that about 200 Chinese white dolphins were living in waters around the territory.
The dolphins were mainly distributed in the western waters of Hong Kong near the Pearl River Estuary, she explained.

Some dolphins were getting stranded in waters close to Hong Kong.

'These stranded Chinese White Dolphins were mainly found in the waters and along the coast of Lantau Island, Tuen Mun, Sha Chau and Lung Kwu Chau,'' Dr Liao said in a written reply.

She said that in the past three years, 28 dead white dolphins had been found. Five were found dead in 2006, 13 in 2005 and 10 in 2004. Statistics for 2007 were not provided.

The environment secretary said 12 of the carcasses were over two metres long, indicating they were adults. The remaining dead dolphins were juveniles or babies.

Dr Liao said most carcasses had not showed excessive levels of contamination.

'The AFCD [Agricultural Fisheries and Conservation Department] had previously analysed liver tissue samples of 25 Chinese White dolphins and the results indicated that the level of heavy metal contaminants in them was all at normal level,' Dr Liao told the Legco.

The carcass found in February was badly decomposed and the cause of death could not be determined, she said.

Dr Liao said the government was planning a dolphin conservation programme. This would include:

  • Monitoring the number of dolphins and their distribution on a long-term basis;
  • Assessing heavy metals and organic contaminants accumulated in dolphin carcasses;
  • Establishing marine parks to protect dolphins and their habitat; and
  • Working with Guangdong authorities to protect dolphins in the Pearl River Estuary.

'The AFCD commissioned the City University of Hong Kong to conduct a two-year study on the heavy metals and organic contaminants in the dolphins' bodies in late 2005,' she added.

The study would be completed by the end of 2007.

Hong Kong's dolphin population has declined considerably in the last decade, according to the Hong Kong Dolphin Conservation Society. The society's website says that between 1996 and 2005 there was a 40 per cent drop in local dolphin numbers.

The society said the AFCD estimates the dolphin population is probably between 91 and 207 in Hong Kong waters. But this depends on seasonal variations.

It said dredging work carried out to build Chek Lap Kok extensively damaged the marine habitat. The airport, one of the world's largest, was opened in 1998.

'Reclamation devastates coastal ecology and reduces the amount of fish available to the dolphins to feed on,' the society said.
It added that injuries from ship propellers are also a threat as well as sea-borne pollution.

The World Wide Fund for Nature Hong Kong has also blamed dredging related to reclamation work. 'Dredging for West Kowloon reclamation resulted in millions of tonnes of toxic mud needing a disposal site. Once again an important area for dolphins was chosen to dump the waste,' it said.

The WWF said toxic materials could 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 around many Asian countries, including the Arab states and Malaysia.