The Indo-Pacific Humpback Dolphin is a variety of Chinese white dolphin ('Sousa chinensis; Chinese: 中華白海豚; pinyin: Zhōnghuá bái hǎitún). This variety inhabits the eastern portion of the species range, in Southeast Asia and Australia. Some biologists regard the Chinese white dolphin as a separate subspecies, Sousa chinensis chinensis, from the Plumbea-type Indo-Pacific humbacked dolphin, which lives in the western part of the species range, from east Africa to India. However, DNA testing has indicated that the Chinensis-type dolphins from Southeast Asia are more closely related to the Plumbea-type dolphins than they are to the Chinensis-type dolphins from Australia.
An adult Chinese white dolphin is white or pink and may appear as an albino dolphin to some. Uniquely, the population along the Chinese coast has pink skin, and the pink colour originates not from a pigment, but from blood vessels which were overdeveloped for thermoregulation. The body length is 2 to 3.5 m (6 ft 7 in to 11 ft 6 in) for adults 1 m (3 ft 3 in) for infants. An adult weighs 150 to 230 kg (330 to 510 lb). Chinese white dolphins live up to 40 years, as determined by the analysis of their teeth.
At birth, the dolphins are black. They change to grey, then pinkish with spots when young. Adults are white.
Chinese white dolphins rise to the water surface to breathe for 20 to 30 seconds and after that, they will dive into deep water again. A calf dolphin surfaces from the water twice as much as an adult, because calves have smaller lung capacities than adults. Adult dolphins can stay underwater for about two to eight minutes, but a calf can only stay underwater for one to three minutes. Adult dolphins rarely stay under water for more than four minutes. They sometimes leap completely out of the water. They may also rise up vertically from the water, exposing the dorsal half of their bodies. A pair of protruding eyes allows them to see clearly in both air and water.
Chinese white dolphins are sociable creatures and live in groups of three to four. Female white dolphins become mature at 10 years old, while the males become mature at 13 years old. They usually mate from the end of summer to autumn. Infant dolphins are usually born 11 months after the mating. Mature females can give birth every three years, and the parental care will last until their offspring can find food themselves.
The white dolphin has been threatened, mostly by Hong Kong's pollution. Conservationists warned that Hong Kong may lose its rare Chinese white dolphins, also known as pink dolphins for their unique colour, unless it takes urgent action against pollution and other threats. Their numbers in Hong Kong waters have fallen from an estimated 158 in 2003 to just 78 in 2011, with a further decline expected when figures for 2012 are released next month, said the Hong Kong Dolphin Conservation Society. "It is up to the government and every Hong Kong citizen to stand up for dolphins. We risk losing them unless we all take action," said society chairman Samuel Hung. A tour guide from Hong Kong Dolphinwatch spotted a group of pink dolphins helping a grieving mother support the body of her dead calf above the water in an attempt to revive it. The scene, captured on video and widely shared on Facebook, has raised fresh concerns about the dwindling population in a city where dolphin watching is a tourist attraction. "We’re 99 percent certain the calf died from toxins in the mother’s milk, accumulated from polluted seawater," said Hong Kong Dolphinwatch spokeswoman Janet Walker, who added it was the third such incident reported in April alone. Fewer than 2,500 of the mammals survive in the Pearl River Delta, the body of water between Macau and Hong Kong, with the majority found in Chinese waters and the rest in Hong Kong.
Hong Kong Dolphinwatch has been running boat trips to visit the Chinese white dolphins for the past 12 years. The dolphins mainly live in the waters of Lantau North, Southeast Lantau, the Soko Islands and Peng Chau. The trips are done primarily with the purpose of raising awareness amongst Hong Kong residents regarding the dolphins, and the operation strictly adheres to the code of conduct for dolphin watching activities.Ten percent of the profits of the organisation goes into research for Friends of the Earth (HK)'s Water Action Group, which is a charity aimed to raise public awareness of Hong Kong's coastal environment.
There have been some recent reports of dolphin watching practices that have further endangered the Chinese white dolphins, such as in Sanniang Bay in Qinzhou and off Xiamen. However, these generally are small, locally organised one-off tours or private pleasure boats that do not adhere to the Hong Kong Agricultural and Fisheries Department's voluntary code of conduct. The basic principles of these codes of conduct are to always observe the dolphins from a distance, and to not attempt to physically contact, feed or harm the dolphins. Additionally, boats should maintain a slow and steady speed, not exceeding 10 knots, and the boat should always maintain a parallel movement to the dolphin's course.
- 1637: The Chinese white dolphin was first documented in English by the adventurer Peter Mundy in Hong Kong near the Pearl River. The species are attracted to the Pearl River Estuary because of its brackish waters.
- 1765: Pehr Osbeck gives the first scientific description of the species.
- Late 1980s: Environmentalists started to pay attention to the Chinese white dolphin population.
- Early 1990: The Hong Kong public started to become aware of the Chinese white dolphin. This was due to the side effects of the construction of the Chek Lap Kok Airport. It was one of the world's largest single reclamation projects: the reclamation of nine square kilometers of the seabed near Northern Lantau, which was one of the major habitats of the dolphins.
- Early 1993: Re-evaluation of the environmental effects of the construction of Chek Lap Kok Airport. This alerted eco-activists such as those from the World Wide Fund for Nature in Hong Kong, in turn bringing media attention on the matter. Soon enough, the Hong Kong Government began getting involved by funding projects to research on the Chinese white dolphins
- Late 1993: The Agriculture, Fisheries and Conservation Department was founded.
- 1996: Dr. Thomas Jefferson began to conduct research on the Chinese white dolphins in hope of discovering more about them.
- 1997: The Chinese white dolphin became the official mascot of the 1997 sovereignty changing ceremonies in Hong Kong.
- 1998: The research results of Dr. Thomas Jefferson was published in "Wildlife Monographs".
- 1998: The Hong Kong Dolphinwatch was organized and began to run dolphin watching tours for the general public to raise the public's awareness of the species.
- 2000: The Agriculture, Fisheries and Conservation Department started to conduct long-term observation of the Chinese white dolphins in Hong Kong.
- 2000: The population of Chinese white dolphins has reached around 80–140 dolphins in the Pearl River waters.