Based on historic sightings, Chinese white dolphins have inhabited the waters around the mainland since the 1600s and could once be spotted from Macau to the coast of Shanghai. Despite their name, the dolphins are recognized for their pink color, which develops as they age. These days there are four major populations in Chinese mainland, including the Pearl River Estuary, Xiamen, Beibu Bay and Leizhou.
Samantha Lee, Senior Marine Conservation Officer with the World Wildlife Fund, explains that the “population of the Chinese white dolphin in the Pearl River Estuary, which includes the waters of Hong Kong and Macau, is unique. Not only is it the largest population remaining in China of around 2,000 individuals, but it inhabits a polluted estuary with intense human activity.”
They can be spotted in the north and south waters off Lantau Island. Typically living in groups of four, they like to stick close to shore but will range about 200 kilometers. There are about 20 different types of fish these carnivores consume, including lion-head fish, croaker and mullet. They can be seen following behind fishing boats, feasting on the catch which falls off the back. The same vessel that feeds them can also harm though – many of the rose-hued mammals have visible marks from fishing gear and propeller injuries.
Aside from overfishing and busy maritime traffic, large building projects are a major threat to dolphin habitat. The construction of the Hong Kong-Macau-Zhuhai Bridge and the addition of a third runway at Hong Kong International Airport will result in the permanent loss of at least 1,000 hectares. Some require underwater construction such as piling, which creates noise that interferes with echolocation, a type of sonar dolphins use to communicate, navigate and hunt.
Surrounded by a highly built-up and industrialized landscape with increasing reclaimed shorelines, the cumulative degradation has seen a significant decrease in sightings in recent years, in particular of young dolphins. “The latest monitoring study of just Hong Kong waters recorded a significant drop in dolphin abundance from 158 individuals in 2003 to 61 in 2013,” says Lee. “The dramatic drop hints that the dolphin's future is in grave danger.”
When the Chinese white dolphin was chosen as the mascot of the 1997 handover of Hong Kong, interest was kindled in protecting the playful cetaceans. The WWF has been lobbying the government to designate known habitat areas as marine parks and to develop a comprehensive management plan. They are also “encouraging the development of similar efforts in the Pearl River Delta using Hong Kong as best practice in dolphin management,” says Lee.
Greater awareness in the last decade also saw the start of dolphin-seeking tours. While these can be beneficial for research and funding, the Hong Kong Dolphin Conservation Society notes that it has caused “problems with irresponsible dolphin-watching practices and activities.” They offer information on how to choose an operator with the least negative impact, in addition to a limited number of tours they run themselves.
// WWF: www.wwf.org. Hong Kong Dolphin Conservation Society: (852)2866 2652, info@hkdcs.org
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