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November 29, 2010

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Plight of the Baiji

THE Yangtze River dolphin and finless porpoise on the brink of extinction.

The Baiji dolphin (Lipotes vexillifer) was once a common sight in the Yangtze River. This was verified by Dr Zhou Kaiya from Nanjing University, who has studied the species for many years. Eyewitness accounts from fishermen in seven provinces have provided strong support for the accuracy of historical records - that the Baiji indeed once flourished in the river.

However, since the 1990s, no more Baiji have been sighted in the sections upstream of Shashi in Hubei Province and downstream of Jiangyin in Jiangsu Province.

Between 1997 and 1999, two expeditions to search for the Baiji were organized by the Ministry of Agriculture and the Institute of Hydrobiology of the Chinese Academy of Sciences. The first expedition found 13 dolphins; the second only four.

Another observation conducted in 2003 by the institute found zero dolphins. The world was further stunned in 2006 when the six-nation Yangtze Freshwater Dolphin Expedition announced its findings. Not a single dolphin was found after six weeks of surveying the Yangtze River, and the Baiji dolphin was declared functionally extinct.

End of the road

The Baiji was wiped out by human interference in their habitat, says Dr Wang Ding, deputy director of the Institute of Hydrobiology.

"The rapid degradation of the Yangtze River, the construction of dams and canal locks on lakes along the river and the widespread use of destructive fishing methods have directly affected the Baiji, as these greatly reduce the dolphin's food sources," Wang says.

The Baiji have also been exposed to many hazards in the river. Since 1998, dead Baiji dolphins have been discovered with broken skulls, multiple fractures and wounds caused by fishhooks. An explosion to clear a waterway in Lake Honghu, Hubei Province, killed a family of four dolphins - including two pregnant females.

Human population pressure and economic growth along both sides of the river have led to a rapid decline in the Baiji population. In 2004, a panel of 14 international experts declared the Baiji the world's most endangered cetacean. Furthermore, as the Baiji is the only known member in its family (Lipotidae), its demise spells the end of not just one species, but an entire natural family.

With eyes smaller than green peas, the dolphin has poor eyesight. It relies on its highly developed sonar to navigate and find food in the silt-laden waters of the Yangtze.

The Baiji's sophisticated sonar is of great interest to science, with potential applications in diverse fields such as bionics, medicine and defense.

The passing of Qiqi, a Baiji that died after 20 years of care at the institute, is still mourned by its caregiver Dr Wang Kexiong.

"Although other river dolphins and porpoises also possess their own sonar systems, none are as advanced as that of the Baiji," says Wang, who still finds it hard to accept the fact that Qiqi is gone.

The doctor had recorded Qiqi's unique calls and whistles before it died and he still listens to them every day as he works on his laptop computer.

In practice, a species is considered extinct when no members are found in their natural habitat for 50 consecutive years. Although Wang Kexiong, Wang Ding and other experts believe there could be a handful of Baiji dolphins left, they fear for the fate of these last survivors.

Last call

Wang Ding is worried.

"Today finless porpoises are in the same state as the Baiji 20 years ago," he said during the 2006 Yangtze Freshwater Dolphin Expedition. Up until the third day of the search, the scientists only found 20 porpoises - far less than the 100 they expected. There are only around 1,400 porpoises left.

A threatened species on the Red List of the International Union for Conservation of Nature, the finless porpoise is currently a Grade-2 protected species in China, and is being upgraded to Grade-1 status. Some scientists predict that if nothing is done to stop the environmental degradation in the Yangtze River, the porpoise will be gone in less than 100 years.

The finless porpoise is a small cetacean found in rivers and coastal areas in South and East Asia. There are three distinct subspecies. One is found in the Indian Ocean and South China Sea (Neophocaena phocaenoides phocaenoides); another is found in northern China, South Korea and along the coast of Japan (Neophocaena phocaenoides sunameri); and a freshwater subspecies (Neophocaena phocaenoides asiaeorientalis) is found in the lower and middle reaches of the Yangtze River, as well as the Poyang and Dongting lakes.

Although the finless porpoise and the Baiji are not related, they share the same habitat and the same food. Thus, the Baiji can be found where there are plenty of porpoises, and vice versa. To conserve both species, it is crucial to restore the fish stock in the Yangtze.

Presently, land-reclamation projects have reduced the surface area of the water, while dam construction has prevented the migration of four major fish species - the black carp, grass carp, silver carp and bighead carp. The damming has also flooded eight key spawning sites for these fish, reducing fish fry quantities by 97 percent.

"There is now hardly any plankton in the Yangtze River," says Dr Beat Mueller, a Swiss scientist on the 2006 Yangtze Freshwater Dolphin Expedition. "I put a net in the river to collect plankton for 10 hours, and all I got were two shrimp less than a centimeter long. It's hard to imagine how fish can survive in waters like that."

However, there may yet be reason to hope. In July 2005, a finless porpoise under the care of the Institute of Hydrobiology gave birth to the first finless porpoise born in captivity, rekindling hope for this endangered species.

River dolphins represent a rather primitive form of cetaceans, and are classified into four natural families. The Ganges and Indus river dolphin are limited to the South Asia subcontinent; the Amazon river dolphin is found only in the Amazon and Orinoco rivers; the La Plata dolphin lives in estuaries on the west coast of the Atlantic Ocean; and the Baiji, the most endangered river dolphin, is exclusive to China.

Except for the Amazon dolphin, the other freshwater dolphins are found in densely populated areas - these include the Indus, Yangtze and Indian rivers, where one-sixth of the world population resides.

International efforts

Research by the World Wide Fund for Nature in India has found less than 2,000 Ganges river dolphins in the Indus and Yarlung rivers, downstream of the Yarlung Tsangpo River in China. However, with the efforts of the WWF, the number of Ganges river dolphins in a 164-kilometer section has increased from 22 to 42 in 10 years.

Although the number has declined due to damming projects in the 1930s, the Indus river dolphin is still slightly better off than the Baiji. During the dry season, the drastic drop in the water level creates many "death traps" for the Indus river dolphin. During the wet season, the dolphins may swim into the 60,000-kilometer irrigation network connected to the Indus River.

These networks have segregated dolphin population and led to the entrapment of dolphins in irrigation canals, which could lead to death if not released in time. The WWF has taken action to save these dolphins, rescuing 34 trapped dolphins since 2000.

The emphasis that other countries place on wildlife conservation was illustrated by Dr Zhang Xianfeng, a scientist from the Institute of Hydrobiology. One day, while he was doing research work with the Japanese National Research Institute of Far Seas Fisheries, a local environmental protection organization issued a notice, saying that a sperm whale had been stranded on a beach.

Zhang was amazed at the speed the various authorities in Japan worked together during the rescue process, which was reported in the press and tracked with a helicopter. A similar event was also witnessed by Wang Ding in the 1990s, while he was pursuing his doctorate degree in the United States.

Whale watching

On conservation efforts in China, a cetacean expert has this to say: "In China, the monitoring authorities, fisheries, police and environmental protection agencies have their own area of responsibility. There is no coordinated effort. When a situation occurs, no individual agency is able or willing to tackle the problem ... nothing much gets done in the end."

In order to prevent the finless porpoise from being the next Baiji, experts in China have proposed a number of conservation measures. One of these, proposed by Wang Kexiong, is a whale-watching program that would allow tourists to get up close and personal to the 400 finless porpoises in Poyang Lake, where most of the porpoises are found today.

An eco-tourism model could educate the public on the importance of conserving the finless porpoise, and also create financial incentives for local communities to protect the ecosystem.

Wang got the idea from a report by the International Fund for Animal Welfare, which outlined the economic and conservation benefits gained from over 10 million whale watchers each year.

The whale-watching industry has grown rapidly in the last 10 years, generating revenues of over US$500 million every year in the United States alone. Whale watching also plays an important part in the Australian tourism industry - in 2005, more than 1.6 million tourists participated in whale watching activities, contributing US$270 million to the Australian economy.

South Korea has also launched a whale-watching program. In Taiwan, although whale watching is relatively new, the industry has attracted thousands of tourists, and the number of tourist boats is increasing every year.

However, several issues need to be addressed before a whale-watching program can be implemented.

Poyang Lake would first need a major overhaul. Today, there are too many construction projects in the lake, such as sand excavation, bridge and road construction, which have a great impact on the porpoise.

The lake is also heavily polluted. Passenger boats from the Yangtze River used to obtain their drinking water from the lake, but now construction workers in the lake have to bring their own drinking water.

The area between Poyang Lake and the Yangtze River used to be where most finless porpoises were found. However, the Lake Poyang Highway Bridge and Tongjiu Railway Bridge have restricted porpoise movement between the river and the lake.

To the porpoises' sonar, the densely packed pillars supporting the railway bridge sound like an impenetrable wall, while the din from vehicles above have created much noise pollution that masks the porpoises' echoes.

If the porpoise population was segregated between the lake and the river, this would reduce the gene pool, leaving them more prone to extinction in the event of drastic environmental changes.

Wang has also proposed setting up a nature reserve in Poyang Lake to support a whale-watching program. It is only with a holistic consideration of environmental and human factors that we can stop the porpoise from going the way of the Baiji. This could well be the only way out for the Yangtze finless porpoise.


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