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Chinese White Dolphin

Extinction threat faced by pink dolphins in waters around Hong Kong far greater than expected, study finds

Research by HKU shows not enough ideal habitat under protection, while population is ‘fast approaching its viability threshold’

PUBLISHED : Friday, 24 February, 2017, 9:54pm
UPDATED : Friday, 24 February, 2017, 11:17pm

Pink dolphins in the Pearl River estuary face a far greater extinction threat than previously thought, with crucial habitats in the area disappearing and the species population declining at an annual rate of 2.5 per cent, a study has found.

Researchers from the University of Hong Kong concluded that the Chinese white dolphin – also known as pink dolphins – “face extinction” as not much of their natural environment in Hong Kong and the mainland were under legal protection.

Watch: A look at the dwindling habitat of Hong Kong's Chinese white dolphin

“Unfortunately, our findings indicate that the estuary dolphin population is facing extinction unless effective conservation measures can rapidly reverse the trend,” Dr Leszek Karczmarski, associate professor at HKU’s school of biological sciences, said.

“For conservationists and management authorities, the time to act is now,” he added.

According to the study, approximately 3,000 sq km of habitat crucial to the marine mammals is required for about 2,000 of the animals, excluding the impact of human activities.

Under such ideal conditions, the dolphin population can survive for at least another 40 generations, or about 800 years.

However, the protected marine areas in both Hong Kong and mainland waters span only about 600 sq km, of which little comprises optimum dolphin habitat.

Karczmarski cited another study which found that in Hong Kong, less than 17 per cent of core dolphin spaces and less than 7 per cent of their foraging grounds were under legal protection. The numbers in mainland waters are even smaller.

The dolphin population is declining at a rate of about 2.5 per cent a year and is “fast approaching its viability threshold”, the recent HKU study warned.

Earlier research backed by Ocean Park’s conservation arm in 2014 also found that there were high concentrations of organic pollutants and heavy metals in the Pearl River estuary, which threatened the immune and reproductive systems of the animals.

“To be effective, conservation measures should not only increase the volume of the habitat under protection but also focus all efforts on core areas and key habitats used by the dolphins for their daily needs,” Karczmarski said.