SAD END: A researcher checks a dead Chinese white dolphin in Xiamen, Fujian Province, on June 28, 2004. More dolphin strandings and deaths have occurred in recent years (KANG MIAO)
South China's Pearl River Estuary (PRE) White Dolphin National Nature Reserve has reported more strandings and deaths of the animals since the beginning of 2009.
Statistics provided by the reserve's administrative bureau show that there had been 16 Chinese white dolphin deaths around the PRE as of July 31, among which five occurred in Hong Kong and three happened in Macao.
"It is rare in recent years that so many Chinese white dolphins have died in such a short period," said Chen Xi, an assistant engineer at the reserve.
Chinese white dolphins, also known as Indo-Pacific humpback dolphins, are a highly intelligent marine mammal species. The animal ranges throughout western Pacific coastal waters and the PRE. Chen said there are about 1,000 such dolphins around the 460-square-km estuary area.
But with recent economic development, the white dolphins in the PRE face many threats and are becoming endangered.
Their PRE home range has already substantially shrunk over the past decade because of construction at the new airport on Chek Lap Kok Island and its associated land reclamation. Reclamation has devastated coastal and benthic ecology and reduced the amount of fish available for the dolphins to feed on.
Habitat loss and water pollution are lethal threats, said Samuel Hung Ka-yiu, Chairman of the Hong Kong Dolphin Conservation Society (HKDCS).
On October 28, the Hong Kong-Zhuhai-Macao Bridge construction project was approved and will begin this year. The construction plan shows that the bridge will run across the part of the nature reserve in the PRE.
"Bridge construction may harm the living conditions for the rare dolphins," Hung said.
He said the project's mud pits and reclamation would disrupt dolphins' lives and would cause them to move to other areas.
"We cannot have more development pressure on the dolphins. They won't be able to survive," Hung said.
Although there is still no concrete proof that water pollution impinges directly on dolphins' health, samples collected from their carcasses have revealed high concentrations of chlorine and heavy metals, suggesting that these pollutants are harmful, said Chen Jialin, director of the reserve.
Pollutants are washed into the sea from local discharges and the Pearl River. According to marine environmental quality monitoring data released by the Guangdong Provincial Oceanic and Fishery Administration in May, the total volume of land-based pollutants in Guangdong pouring into the sea was 528,600 tons in 2008. More than 412,000 tons of the total washed into the PRE.
"The high concentration of pollutants that accumulates in dolphin blubber and internal organs might be attributable to its polluted food source, which can contain non-degradable toxic substances," Chen said.
At the same time, a lot of pathogenic bacteria and viruses can be found in PRE waters, thus making the animals even more vulnerable to diseases, which can be fatal.
Heavy vessel traffic also endangers the dolphins, as the PRE is one of the busiest maritime areas around the world. Dolphins would normally avoid swimming in vessel passageways, but some take the risk to search for food.
"Accidents usually involve them being hit by vessels when they rise to the surface to breathe," Hung said.
Chen said over-fishing is another crucial problem to the dolphins.
"Over-fishing can be found everywhere," he said. "Although fish reproduce, their size gets smaller and smaller. In the end, only small fish can survive. The dolphins eat fish. If the size of the fish becomes smaller and the reproduction time becomes longer, the dolphins starve to death. Chinese white dolphins are near extinction because of the broken food chain in the marine world."
A favorite feeding strategy of the dolphins is to follow fishing vessels for fish that escape from trawling nets. But they also risk being entangled by following that strategy.
"The dolphins often get entangled in fishing nets," Chen said. "As they have to surface to breathe, they drown if they have become caught up in a net."
The dolphins are also threatened by disturbances from tourist boats and underwater noise caused by vessels.
Because of the numerous risks the dolphins face daily, governments at different levels and local environmental groups are working on measures to protect them, hoping they will continue to thrive in China's coastal waters.
PEARL OF THE SEA: A little girl takes photos of a Chinese white dolphin model at the First China Ocean Exposition on July 18. The event was held in Zhuhai, Guangdong Province, on July 18-20 (CHEN YEHUA)
In 1988, the Chinese white dolphin was listed as a first-class protected wild animal in the Name List of Specially-Protected Wild Animals of China that was issued by the State Council, and was also included in the International Trade Treaty for Endangered Wild Animals.
In July 1996, the Hong Kong Agriculture and Fishery Department hosted an international forum for protecting Chinese white dolphins living off of Hong Kong's shores. The same year, Taiwan also initiated a project to save the dolphins around Taiwan.
Hong Kong's dolphins are mainly protected under two ordinances, the Wild Animal Protection Ordinance and the Animals and Plants (Protection of Endangered Species) Ordinance, which are both regulated by the Hong Kong Government's Department of Agriculture, Fisheries and Conservation, according to Hung. The Wild Animal Protection Ordinance protects animals from harassment, harm, capture or killing.
The Animals and Plants (Protection of Endangered Species) Ordinance locally enforces the Convention on International Trade of Endangered Species of Wild Fauna and Flora (CITES) to prevent the illegal export, import or sale of endangered species and their body parts. The Chinese white dolphin is listed in Appendix I of CITES, which means any trade in the animal for commercial purposes is prohibited around the world.
Andy Cornish, Director of Conservation for the World Wide Fund (WWF) in Hong Kong, believed marine parks are the best way to conserve Chinese dolphins.
If governments set up marine parks and abandon fishing activities within their boundaries, the food deficit is solved, he said. In addition, setting up marine parks can stop development projects involving reclamation, decreasing the water pollution in the habitat.
Hong Kong has so far established four marine parks to protect the dolphins. Under the Marine Parks and Marine Reserves Regulation, all vessels must limit their speed to 10 knots an hour in the marine parks to avoid hitting the dolphins. Trawlers are prohibited from operating in the parks to protect local fish stocks and eliminate the risk of accidentally catching dolphins.
In August 1997, the Fujian Provincial Government founded the Xiamen Chinese White Dolphin Natural Reserve. It was upgraded to a national natural reserve in November 1999.
In October 1999, the Guangdong Provincial Government created the provincial level PRE Chinese White Dolphin Natural Reserve. That reserve, too, was upgraded to a national natural reserve in July 2003.
In August 2003, Guangdong Province's Shantou City approved the Laiwu and Longtou bay ocean zones as sub-provincial level Chinese white dolphin natural reserves.
Long-term research and monitoring is crucial to dolphin conservation, by which scientists can learn more about the ecology, status, trends and changes in abundance and distribution of the dolphins, said Chen.
On August 11, the Guangdong Oceanic and Fishery Administration organized a large-scale monitoring effort using advanced technology to investigate hydrology, water quality, meteorology and the number of Chinese white dolphins.
"If the number of dolphins plunges dramatically in a year, researchers can detect it right away, find out the cause and implement remedial measures," Chen said.
Information collected from dolphin carcasses helps further understand their status.
"Their liver reveals the amount of toxic heavy metals they have accumulated, which can help researchers work out how environmental pollution directly affects them," he said.
Chen said researchers and experts at the PRE Chinese White Dolphin National Nature Reserve are trying to artificially breed the white dolphins.
"It is a tough scientific question for us, but we have enough confidence to conquer it. Once it gets cracked, we can find a broader world for the dolphins," he said.
Education is a vital part of dolphin conservation, said Hung.
"The efforts spent by a few conservationists and the government will be in vain if public recognition and support is lacking," he said.
For years, governments and environmental groups have been holding talks regularly, along with exhibitions and contests for schools and organizations. They have published different kinds of dolphin booklets and posters to promote public awareness of the dolphins and their conservation.