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Not too long ago, a Dolphin Pod listener wrote in to ask us if we would consider producing a podcast about the lesser known members of the dolphin family. Often times, so much of the research conducted on dolphins focuses on those species that are easy to study: species like the bottlenose dolphins which live near the coast. So it is easy to overlook those less-often-encountered species. In this week's episode, we will discuss one species of dolphin that has, for many years, managed to slip under the radar screen, but recently made its way into the news for all of the wrong reasons.
The Dolphin Pod was saddened to learn that, as of December 2006, the Chinese river dolphin, also known as the baiji, has been declared functionally extinct. Sometimes called the white dolphin or the Yangtze River dolphin, the scientific name for the baiji is Lipotes vexillifer. It is a painfully ironic fact that the scientific name for this now extinct species translates to: left behind flag bearer.
Like some of the other river dolphins species, the baiji is peculiar looking; it has tiny eyes and a long thin rostrum. Baiji have very poor eyesight and rely on echolocation to navigate and hunt for prey in the murky waters of the Yangtze River. The baiji, a dolphin that was declared a National Treasure by the Chinese government in 1975, is one of five official 'river dolphins', and one of the eight species of dolphin that spends time in freshwater rivers. These dolphins include the Susu (actually two species living in the Indus and Ganges rivers in India), the Irrawaddy dolphin (a coastal dolphin that often enters the Ganges, Mekong, and Irrawaday rivers), the Boto and Tucuxi dolphins, both living in the Amazon river, and the Yangzte Finless Porpoise. Both the Yangtze finless porpoise and the baiji live in the Yangtze River, but they are in fact two separate species, despite sometimes both being referred to as the Chinese river dolphin. There is also the La Plata dolphin that inhabits the estuaries of South America, with some populations living in rivers. The baiji is, was, endemic to the Yangzte River, meaning that it was found no place else on earth.
Most river dolphins face an uphill battle against extinction; some of these species are listed as endangered, whereas others are critically endangered. The reason for this is quite simple: where you find rivers, you also find humans. Human influence is the major threat to river dolphins, and comes in many forms: accidental entrapment in fishing gear, pollution, collision with boats, destruction of habitat, reduction of range due to damming, over-fishing, underwater disturbances like boat noise and dynamite blasts, and accidental and sometimes even deliberate bycatch (that is, being caught by fisherman). Scientists believe that it was a combination of these factors that has lead to the extinction of the baiji. There was even a period in Chinese history, during the rise of Mao Zedong, when the baiji was actively hunted. Because of its traditional religious status as a venerated sacred animal, the communist government sought to eradicate the baiji. It was hunted relentlessly, and the carcasses were used for meat, oil, and leather. Doubtless this period in history played a major role in the decline of the species.
Before this unfortunate time, there were plenty of baiji to be found in the Yangtze: in the 1950s, as many as 6,000 baiji were recorded. According to the baiji.org Foundation, a survey in the 1980s found that their numbers had been reduced to less than 400 - placing them on the critically endangered list. The Chinese government granted the baiji protection from harm in 1983 and attempts were made by various organizations to take steps to protect the baiji, but an effective plan could not be established. Despite the breeding and conservation efforts of scientists, conservation groups and the modern Chinese government, a survey in 1997 counted only 13 baiji. The last confirmed sighting of a baiji was in 2004.
The news concerning the extinction of the baiji originates from recent scientific efforts to count the number of baiji still found in the Yangtze. An expedition led by the Ministry of Agriculture comprising scientists and volunteers from the Swiss Federal Institute of Aquatic Science and Technology (Eawag), the National Oceanic and Atmospheric Administration (NOAA), the Hubbs-Seaworld Institute from San Diego and the Fisheries Research Agency in Japan, spent six weeks in November and December searching the Yangzte River for any sign of a living baiji. On Wednesday, December 13, 2006, the group returned from their expedition without a single sighting. The scientists were obliged to declare the baiji 'functionally extinct' - this means that there might still be a handful of baiji left somewhere in the Yangzte right now, but their numbers are likely too few to ever recover. "It is possible we may have missed one or two animals", said August Pfluger, head of Swiss-based baiji.org Foundation and co-organizer of the expedition. "We have to accept the fact that the baiji is functionally extinct. It is a tragedy, a loss not only for China, but for the entire world", said Pfluger.
According to the baiji.org website, the scientists also surveyed the population of the Yangtze Finless Porpoise, and sighted less than 400 individuals of this species. "The situation of the finless porpoise is just like that of the baiji 20 years ago", said Wang Ding, deputy director of the Institute of Hydrobiology Wuhan. "Their numbers are declining at an alarming rate. If we do not act soon, they will become a second baiji".
Like the baiji, the fate of the Yangtze finless porpoise lies in the hands of human beings. Although the future for the Yangtze finless porpoise, like many of the river dolphins, is bleak, we should not give up hope. As the first large mammal species to become extinct solely from the unsustainable over-exploitation of the marine environment, the baiji - the left behind dolphin - should serve as a lesson to us all. If we as individuals, communities, and nations take the story of the baiji to heart, there is hope that other species, like the finless porpoise, will be spared needless and preventable extinction.
[PIC]http://www.whb.ac.cn/english/upload/20074119245599594.jpg[/PIC]
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