‘No optimism’ for survival of Chinese white dolphin in Hong Kong waters
Experts warn of a critical juncture in the species regional existence, as construction works invade its habitat and marine parks don’t seem to help
The Chinese white dolphin – the iconic pink-coloured sea mammal selected as the symbol of Hong Kong’s handover to the mainland exactly 20 years ago – has seen its regional numbers drop to a new low since population records began in 2003.
Experts warn of a “critical juncture” in the species’ existence in Hong Kong waters, as it is besieged by multiple infrastructure projects in its main habitat of northern Lantau Island.
From 87 dolphins in 2010-11, numbers fell to 65 in 2015-16 and 47 in 2016-17, a sharp 27 per cent drop, according to the latest report by the Agriculture, Fisheries and Conservation Department. The biggest drop was recorded in southwest Lantau.
The estimate was 188 dolphins in 2003, the first year annual record-keeping began for Lantau’s west, northwest, and northeast waters, and from 2010, the southwest region.
Calf numbers have also dipped to their lowest – only 17 were sighted over the past year.
Dr Samuel Hung Ka-yiu of the Cetacean Research Project, which conducts the study, said the outlook was beyond dismal.
“Numbers drop every year but usually there are at least some bright spots. In recent years for example, we saw dolphins taking refuge further south ... and they were still reproducing,” he said. “There are absolutely no barometers of optimism this year.”
With most of the Hong Kong-Zhuhai-Macau bridge nearly completed, numbers should have in theory rebounded, he said. Instead, they have fallen.
Hung said this was partly due to high-speed ferries from the airport’s Sky Pier being diverted through core dolphin habitat and construction works beginning for a third runway last summer.
“Reclamation destroys dolphin foraging habitat and marine traffic increases the collision risk. Also, the underwater noise generated inhibits their echolocation capability,” Samantha Lee, WWF Hong Kong’s conservation manager for oceans, said. “These disturbances threaten the survival of the remaining dolphins.”
The government said it was setting up new protected marine parks as part of its conservation strategy. But latest figures suggest that even the existing parks are failing to attract dolphins.
Dolphin usage of the Sha Chau and Lung Kwu Chau park off north Lantau fell 85 per cent from 2004. No dolphins at all were sighted at Brothers Marine Park, which was set up as a compensation measure for the reclamation works of the bridge.
Hung said there was a need for a new park for western Lantau and to link up parks in the north with the new southwest and Soko Islands park.
Encounter rates of Chinese white dolphins have progressively dropped from about 10 sightings per 100km in the surveyed areas to seven in 2013 and just 4.1 over the past year.
“A comprehensive survey in the Pearl River estuary is urgently needed to get a better understanding of how the entire dolphin population is doing. We hope that more resources can be given to the department on future dolphin conservation work,” Lee said.
WWF-Hong Kong also urged the government to designate the West Lantau Marine Park as a protected area for remaining dolphins.
“We’ve reached a critical juncture. It’s now life or death for [the dolphins],” Hung said.