Yangtze River Dolphin - Lipotes vexillifer
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Photo: The Baiji or Yangtze River Dolphin (Lipotes vexillifer). Photo copyright:baiji.org foundation, Steven Leatherwood. All right reserved.
Image: A paining of the Baiji or Yangtze River Dolphin (Lipotes vexillifer). Created by Alessio Marrucci for university work in 2006. This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
|TSEW Status||Possibly Extinct (PE), Year assessed: 2010|
|IUCN Status||Critically Endangered (CR), Year assessed: 2008|
|English Name||Baiji, Yangtze River Dolphin, Changjiang Dolphin, Chinese Lake Dolphin, White Flag Dolphin, Whitefin Dolphin|
|Croatian Name||Baiji, Kineski Riječni Dupin, Kineski Jezerski Dupin, Jangce Dupin|
|Dutch Name||Chinese Vlagdolfijn, Baiji|
|French Name||Baiji, Dauphin de Chine, Dauphin Fluviatile de Chine, Dauphin du Chang Jiang, Dauphin du Yang Tsé|
|German Name||Chinesischer Flußdelphin, Chinesische Flussdelfin, Jangtse-Delfin, Baiji|
|Lithuanian Name||Kinijos Ežerinis Delfinas|
|Polish Name||Delfin Chiński|
|Russian Name||Озёрный дельфин|
|Spanish Name||Baiji, Delfín de China|
|Swedish Name||Baiji, Asiatisk Floddelfin, Asiatisk Delfin, Kinadelfin, Vitflaggsdelfin, Yangtzedelfin|
This species was listed under the family Platanistidae in the 1996-2002 IUCN Red Lists of Threatened Species. Some authors prefer to place it rather in the family Iniidae. (Reeves, Smith, Wang & Zhou 2005)
The species has been listed as Critically Endangered since 1996, but in 2007 it was reassessed as Critically Endangered and flagged as Possibly Extinct. Further survey work is essential to confirm whether this species still exists or if it is indeed now extinct; for example, a reported sighting of the species in August 2007 required confirmation. Chinese media reported that a businessman in Tongling City in east China’s Anhui Province filmed “a big white animal” with his digital camera on 19 August. Professor Wang Ding, a leading scientist at the Institute of Hydrobiology of the Chinese Academy of Sciences later confirmed that the footage could be showing the Baiji dolphin (WWF 2007), but he couldn't rule out the alternative possibility that it was a Yangtze Finless Porpoise, Neophocaena phocaenoides asiaeorientalis (Turvey, 2008). The Sixth Extinction Website agrees with WWF and many scientists that this species is “functionally extinct”, but also that it is still too early to declare its extinction. (IUCN 2007; Smith et al. 2007; WWF 2007)
Video: A Reuters video on the August 2007 sighting of the Baiji with a part of the videotape made by a Chinese man. Hayley Platt reports. © Reuters 2007. All rights reserved. (Reuters article on the Baiji sighting.)
The Baiji was a streamlined dolphin with a long narrow and slightly upturned beak-like snout and a flexible neck. They had a rounded melon, elliptical and oriented longitudinally blowhole, low triangular dorsal fin and broad, rounded flippers. The very small eyes, located high on their heads, were functional, but its sight was reduced. The flippers were rounded. They had 30-36 teeth per side of both the upper and lower jaws. This species had 30-36 teeth per side of both the upper and lower jaws. Its dorsal colour was pale blue-grey to grey, while ventrally they were white to ash-white.
Image: Size comparison of a baiji (Lipotes vexillifer) to an average human. Created by Chris Huh on 7 March 2007. A full resolution version can be found at Wikimedia Commons. The copyright holder of this work has release it into the public domain. This applies worldwide.
The bigger females ranged from 185 to 253 cm in length and weigh 64-167 kg, while males ranged from 141 to 216 cm in length and weigh 42-125 kg. The minimum estimate of this species' lifespan is 24 years, provided by the estimated year of age of one wild-caught baiji, based on dentition. (Nowak 1999; Zhou 2002; Culik 2003; Poor & Grigg 2003; Massicot 2006)
The Baiji preyed on fish of many sizes and various species, including both surface and bottom feeders (Chen et al. 1997). During short dives, they used their long beak-like snouts to probe for food in the muddy river bottom in the shallow water near sandbanks or close to the mouth of tributaries of the river. (Poor & Grigg 2003)
Little is known about the reproductive activities of baiji (Poor & Grigg 2003). Sperm density in males varied seasonally and ovulation was periodic in females. The mating season peaked in spring and in autumn. The Baiji's gestation period estimates range from 6 to 12 months. Every two year, the females gave birth to one 80 cm long calf (Nowak 1999), with a peak calving season appearing to be from February to April (Zhou 2002; Culik 2003). The calves were carried by their mothers close to the side of their bodies while swimming, diving and breathing at the surface. The nursing period is unknown. (Poor & Grigg 2003) The females reached sexual maturity at an age of 6 years and about 4 years in males (IWC 2000).
Not much is known about the Baiji's behaviour, due to its cryptic habits. They were usually found in pairs, which aggregated to form larger social units of about 10 individuals. These river dolphins searched for fish during the day and spent most of their time in the vicinity of large eddies. They rested in areas of slow current at night. The baiji navigated in the turbid waters of the Yangtze River with echolocation. They communicated with other baiji using whistles and other acoustic signals. Click here to listen to the baiji whistle (From the baiji.org foundation website). (Nowak 1999; Poor & Grigg 2003)
|Range & Habitat||
The Baiji is endemic to the Yangtze River (Chang Jiang) of China. During the great flood of 1955 some individuals were seen in the Fuchun River, but they disappeared after the construction of a hydropower station in 1957 (Zhou 2002). Historically this species also occurred in the Dongting and Poyang Lakes, both appended water bodies of the Yangtze (Zhou et al. 1977, Chen et al. 1980).
Image: map of China. The former range of the Baiji in the Yangtze River in China is coloured red in the right-hand upper map. Created by 'Papayoung'. The original version of this image can be found at Wikimedia Commons. This image is licensed under the Creative Commons Attribution ShareAlike 3.0 license.
|History & Population||Fossil records indicate that the dolphins may have migrated from the Pacific Ocean to the Yangtze River 20 million years ago. It is estimated that there were 5,000 Chinese River Dolphins when they were described in the Han Dynasty (206 BC - AD 220) dictionary Erya, the oldest extant Chinese dictionary (Wikipedia contributors 2006a). The estimated population size before 1900 was 3000-5000 (Ellis 1993; Leatherwood & Genthe 1995). In the beginning of the 1980s there were still around 400 Baiji (Ellis 1993). On the basis of surveys conducted in 1985 and 1986, it was estimated that the total population was around 300 individuals (Chen and Hua 1989; Reeves et al. 2003). In 1993 their population consisted of about 150 - 240 animals (Ellis 1993) and in 1995 there were estimated to be fewer than 100 individuals (Leatherwood & Genthe 1995). An intensive survey in November 1997 produced a total count of only 13 dolphins (Wang 2000).
QiQi, a baiji male who became the only baiji in captivity when he was rescued in 1980, died in his tank at the Wuhan Institute of Hydrobiology in 2002. (Macartney 2005; Baiji.org Foundation 2006ac)
Later there were confirmed sightings are of two baiji (one large adult, one juvenile) in the Xin-Lou (Honghu) National Baiji Reserve in July 2004, and a large adult baiji in the Tongling Provincial Baiji Reserve in September 2004. (Baiji.org Foundation 2006abc)
On 6 November 2006, the "Yangtze Freshwater Dolphin Expedition 2006" has been launched on Monday in the city of Wuhan in Central China. This 30-member search expedition, under the direction of the Institute for Hydrobiology Wuhan and the Swissbased baiji.org Foundation, made up of both Chinese and foreign researchers conducted a six-week survey of the river. The expedition has been led by the Ministry of Agriculture and brought together world-class experts from institutes such as the Swiss Federal Institute of Aquatic Science and Technology (Eawag), the National Oceanic and Atmospheric Administration (NOAA), the Hubbs-Seaworld Research Institute from San Diego and the Fisheries Research Agency in Japan. The scientists were travelling on two research vessels almost 3500 kilometers from Yichang nearby the Three Gorges Dam to Shanghai into the Yangtze Delta and back, using highperformance optical instruments and underwater microphones. On 13 December 2006, in the city of Wuhan in central China, the expedition drew to a finish without any results. They failed to spot even one of the dolphins. August Pfluger, head of Swissbased baiji.org Foundation and co-organizer of the expedition, said that it possible they may have missed one or two animals, but that we have to accept the fact that the baiji is functionally extinct. The species doesn't occur un sufficient numbers to breed and ward off extinction. (Baiji.org Foundation 2006bc; CNN.com 2006; The Hankyoreh Media Company 2006)
Most people thought the Baiji had become extinct, however Chinese media reported that a businessman in Tongling City in east China’s Anhui Province filmed “a big white animal” with his digital camera on 19 August 2007. Professor Wang Ding, a leading scientist at the Institute of Hydrobiology of the Chinese Academy of Sciences later confirmed that the footage could be showing the Baiji dolphin (WWF 2007), but he couldn't rule out the alternative possibility that it was a Yangtze Finless Porpoise, Neophocaena phocaenoides asiaeorientalis (Turvey, 2008). (IUCN 2007; Smith et al. 2007; WWF 2007)
The Baiji declined due to the following threats to the species: a period of hunting by humans during the Great Leap Forward, entanglement in fishing gear, the illegal practice of electric fishing, collisions with boats and ships, habitat loss, and pollution. (Reeves et al. 2005; Wikipedia contributors 2006a)
The Great Leap Forward (大躍進) of the People's Republic of China was an economic and social plan to use China's vast population to rapidly transform mainland China from a primarily agrarian economy dominated by peasant farmers into a modern, industrialized communist society. The Great Leap Forward was initiated and led by Mao Zedong, and carried out by the Communist Party of China from 1958 to early 1962 (Wikipedia contributors 2006b). The Baiji's traditionally venerated status as "goddess of the river" was denounced and dolphins were hunted for their flesh and skin. A factory producing handbags and gloves from Baiji skin opened but the operation was short-lived because the animals quickly became scarce (Zhou and Zhang 1991; Reeves et al. 2005).
Entanglement in fishing gear was estimated in the 1970s–80s to have been responsible for at least half of observed mortality (Lin et al. 1985, Zhou and Li 1989, Chen 1989, Chen et al. 1997). It was prohibited to use both rolling hooks and fyke nets in the Yangtze River, but enforcement of these prohibitions proved to be very difficult. (Zhou et al. 1998; Zhou and Wang 1994; Reeves et al. 2005)
Electric fishing is "strictly banned" in the Yangtze (Zhou et al. 1998), but is widely practiced, particularly in the centre of the baiji's distribution (IWC 2001). By the early 2000s, electric fishing was considered "the most important and immediate direct threat to the Baiji's survival. (Zhang et al. 2003). The electric shocks kill Baiji outright (Chen and Hua 1989) and unselectively kill other aquatic organisms, including the baiji's prey. (Reeves et al. 2005).
As China developed economically, ship traffic multiplied and the size of the boats grew. Underwater noise pollution made the nearly blind animal prone to collisions with propellers. Propeller strikes have killed and injured baiji (Zhou and Zhang 1991, Chen et al. 1997; Wikipedia contributors 2006a)
Water development has transformed the baiji's habitat by dredged riverbeds, concrete reinforcements and by interrupting their movements upstream of dams, eliminating their access to tributaries and appended lakes, and reducing fish productivity. The building of the Three Gorges Dam, completed in the early 2000s, further reduced the dolphin's habitat and facilitated an increase in ship traffic. Many parts of the Yangtze River have become much shallower because of siltation from deforestation and agricultural development. (Liu et al. 2000; Reeves et al. 2005; Wikipedia contributors 2006a).
Industrialization and the spread of modern agricultural practices have led to an increase of pollutant loads in the Yangtze River. (Reeves et al. 2005)
The baiji had been protected by custom in the past, since the Chinese considered it to be an incarnation of a drowned princess (Burton & Pearson 1987). In China this species was also nicknamed "Giant Panda of the Yangtze River" and "Goddess of the Yangtze" (長江女神), which may reflect the general affection for this dolphin species (Tan 1996).
The Chinese Government began to protect the baiji in 1975 under National Law, and designated it a "National Treasure". Since then, catching or killing a baiji could result in heavy fines or even a long jail sentence. (Baiji.org Foundation 2006) Currently the Baiji is designated in the First Category of National Key Protected Wildlife Species and has full legal protection throughout its range (Reeves et al 2005).
Since the late 1980s, the primary strategy to prevent the baiji's extinction has been to capture as many dolphins as possible and to introduce them into "semi-natural reserves". However, the expectation that sufficient numbers of Baiji could be caught and placed in the reserves to establish a viable ex situ population has proven unrealistic. (Reeves et al 2005)
Image: map with conservation efforts of the Baiji along the Yangtze. 1 = Tian-e-Zhou Oxbow Semi-natural Baiji Reserve; 2 = Shishou City National Baiji Reserve; 3 = Xin-Lou (Honghu) National Baiji Reserve; 4 = Tongling Provincial Baiji Reserve; 5 = Zhenjiang Provincial Baiji Reserve. Created by Peter Maas for The Sixth Extinction Website. This image has been licenced under the Creative Commons Attribution Non-commercial No Derivatives 3.0 licence.
In four protected areas the baiji is actively protected and fishing is completely banned: the Shishou City National Baiji Reserve, the Xin-Lou (Honghu) National Baiji Reserve, the Tongling Provincial Baiji Reserve, and the Zhenjiang Provincial Baiji Reserve. A fifth protected area is an isolated oxbow lake located off of the north bank of the river near Shishou City: the Tian-e-Zhou Oxbow Semi-natural Baiji Reserve. Additionally there are five Baiji Protection Stations in Jianli, Chenglingji, Hukou, Wuhu and Zhengjiang. A "protection station" consists of two observers and a small motorized fishing boat, who make daily patrols, make observations and investigate reports of illegal fishing. (Baiji.org Foundation 2006a)
The baiji is listed in Appendix 1 of CITES since 1979 (UNEP-WCMC 2006), and was listed as endangered on the IUCN Red Lists of Threatened Species of 1986, 1988, 1990 and 1994. Since 1996 this animal is listed as critically endangered. (Reeves et al. 2005)
In theory it would be possible to clone the baiji, because unlike to the Tasmanian tiger or thylacine, fresh DNA has been retrieved and stored in recent years. The Institute of Genetic Resources, Nanjing Normal University (NJNU) has muscle and skeletal samples preserved. These samples were gathered from stranded or incidentally killed individuals from the middle and lower reaches of the Yangtze River. (Yang et al. 2005)
The problem is that a cetacean has never been cloned before. It is also not sure if a surrogate mother can be found in a related species. The other river dolphins are also endangered, and maybe it will not even be possible to use another river dolphin species. Besides, even when it would be technological possible to clone the baiji, than there is probably no suitable habitat left where these clones could live.
The stuffed and enamelled body of the only captive baiji, QiQi, is kept in a specimen room at the Hydrobiology Institute in the central Chinese city of Wuhan (Macartney 2005). Do you know another museum specimen? Contact this website.
The baiji was one of four species of freshwater or river dolphins. The Amazon River Dolphin (Inia geoffrensis) and the La Plata River Dolphin (Pontoporia blainvillei) from South America. The now possible only surviving Asian species is the South Asian River Dolphin (Platanista gangetica), consisting of two subspecies namely: the Ganges River Dolphin (Platanista gangetica gangetica) and the Indus River Dolphin (Platanista gangetica minor).
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|Citation:||Maas, P.H.J. (2010).Yangtze River Dolphin - Lipotes vexillifer. In: TSEW (). The Sixth Extinction Website. <http://www.petermaas.nl/extinct>. Downloaded on .|
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|Updated:||18 August 2010|