Hong Kong's pink dolphins driven out by bridge project

Just 61 dolphins were spotted in Hong Kong waters last year - the fewest in a decade and less than half the number seen back then.

That's according to a study by the Dolphin Conservation Society, which says the drop in the number of dolphins has been particularly acute in the past two years.

The society puts the decline down to construction of the bridge across the southern Pearl River Delta - linking Hong Kong with Macau and Zhuhai - which began in December 2011.

Society chairman Dr Samuel Hung Ka-yiu yesterday described the situation as "dire".

The city's iconic pink dolphins, also known as Chinese white dolphins, are usually found near Lantau Island. The average number fell dramatically from 159 in 2003 to 78 in 2011.

Hung said yesterday that just 17 dolphins were seen in the waters west of Lantau last year - 70 per cent fewer than a decade ago. The number has been more stable in the waters northwest of Lantau in recent years, where 40 were seen last year, he said.

But the biggest decline was in the area northeast of Lantau, where only four dolphins were seen last year. That was 80 per cent fewer than in 2003. The number of dolphin sightings was down 60 per cent in that area from 2011 to 2012, Hung said.

Reclamation work is under way to create a 150-hectare island to be used for border-crossing facilities for the bridge.

Hung said the increase in marine traffic and noise since the work began in 2011 had driven dolphins away from the area. For a few months this year, the society didn't see any dolphins at all near the project site, he said.

He added that building work on the bridge under way in mainland waters was also having an impact on the dolphins, which were most abundant in the Pearl River estuary.

"It's out of Hong Kong's control, but there's no borders when it comes to pollution," Hung said.

He called on the government to set up a promised marine park - in which building, fishing and high-speed vessels would be banned - as soon as possible rather than in 2016, when the bridge is completed. Hung said by then, all the dolphins could have already left the area because of pollution and destruction of their habitat, and any park at that stage would be pointless.

Pollution and noise was also affecting breeding, and Hung said many dolphin calves had been found dead soon after they were born.

He accused the Highways Department of not keeping its promise that the dolphin habitat would be unharmed by the bridge at the time it approved the project. "The damage will be irreversible if the situation continues to deteriorate," Hung said. "I've been working on dolphin conservation for over a decade, and this is the worst situation I've seen."

A spokeswoman for the Highways Department said it had taken measures to minimise the impact of the project on marine ecology. She said the declining numbers could be caused by many factors, including other traffic such as high-speed boats and dolphin-watching tours.