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Ghost in the river: Is the Yangtze River dolphin Extinct?

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The Yangtze River dolphin (also called the baiji) is believed to be extinct.
The Yangtze River dolphin (also called the baiji) is believed to be extinct.

By Brian Gruters

Compared to its chipper, bottlenose cousins, the baiji, or Yangtze River dolphin, was not one to pose for the camera. Its recent notoriety is due to its distinction as either the most endangered cetacean in the world, or the first large mammal to become extinct in more than 50 years. The few images captured of this shy river-dweller swimming through the murky Yangtze are ghostlike.

Size comparison of a Yangtze River dolphin (baiji) and an average human.
Size comparison of a Yangtze River dolphin (baiji) and an average human.

It has been almost 10 years since the baiji was declared “functionally extinct” by researchers with the Yangtze Freshwater Dolphin Expedition, organized by the Chinese Academy of Sciences. In 2006, the group navigated two boats along approximately 2,175 miles of the Yangtze, from the Three Gorges Dam to Shanghai. Despite an already critically low population, they hoped to identify and learn how to assist any remaining dolphins.

The dolphin they were looking for was pale gray, ranging in size up to eight feet long, with a long, narrow rostrum (snout), specialized, like those of other river dolphins in the world, for catching fish. The baiji had smaller eyes than most dolphin species, due to poor visibility in the Yangtze River. Instead, they relied almost exclusively on clicks and whistles to find their way in the water. The baiji was also the sole representative of a unique family of cetaceans—Lipotidae—which would make its extinction a major event: the fourth disappearance of a mammalian family in the past 600 years.

After a six-week search with visual and audio surveillance of the baiji’s known habitat, the researchers were unable to find a single survivor.

“Everyone had a moment of realization that we weren’t going to find anything,” said Samuel Turvey, a researcher with the London Zoo, who was a guest on the search that was managed by an international group of concerned scientists and organizations including the Wuhan Institute of Hydrobiology and Baiji.org, founded by Leigh Barrett.

Conditions in the Yangtze River make life difficult for just about any animal living there thanks to heavy commercial traffic. With industrial boats constantly churning up the silt and debris in the water, a dolphin in the river would be like “a blind man trying to live in a discotheque,” said author Douglas Adams in his book, Last Chance to See (which was turned into a BBC series).

Other man-made features, such as dams, as well as unsustainable and illegal fishing practices also contributed to the baiji’s disappearance. Methods such as rolling hooks and gill nets have contributed worldwide to the decline of small cetaceans, in part because of the difficulty of controlling small, subsistence fishers in economically underdeveloped regions.

After the Yangtze Freshwater Dolphin Expedition published its results, declaring the baiji “likely to be extinct,” other media outlets followed suit. Time, for example, ran the headline “Farewell to the Yangtze River Dolphin” with a story detailing the animal’s extinction. It took less than a year for controversy to arise, however, when a baiji was caught on camera. Organizations like the World Wildlife Fund were quick to appeal for additional conservation efforts.

The Yangtze River dolphin’s plight highlights the difficulty in determining an animal’s extinction, especially one that is hard to locate. Two definitive resources on extinction—the U.S. Fish and Wildlife Service and the International Union for Conservation of Nature (IUCN)—list the baiji as endangered, not extinct. For an animal to be added to the IUCN’s comprehensive extinction list there must be, “no reasonable doubt that the last individual has died.” Furthermore, final closure requires that “exhaustive” surveys in an animal’s known habitat have failed.

The most recent survey of the Yangtze, conducted in 2012, failed again to find evidence of a baiji survivor, and it seems inevitable that future surveys will bear similar results. The baiji population showed a downward trend for decades, frustrating Chinese and international conservationists, but without large-scale changes to the Yangtze ecosystem we can expect more of the same in coming years, Turvey said.

If we can presume to write an epitaph for the baiji, it might be fitting to say something along the lines of let not my disappearance be in vain. The baiji’s cousin, the Yangtze finless porpoise, of which there are fewer than 1,000 remaining, are critically endangered. They also face pressure from illegal fishing and a degraded ecosystem. If we cannot learn from our mistakes, they will end up like the baiji: ghosts in a river.

SOURCES:

http://www.theguardian.com/environment/2007/aug/08/endangeredspecies.conservation

http://www.edgeofexistence.org/mammals/species_info.php?id=1

https://books.google.com/books?id=YY8kAAAAQBAJ&dq=last+chance+to+see&hl=en&sa=X&ved=0CCMQ6AEwAWoVChMIt7CTiLiuyAIVBFw-Ch0DjQOV

http://www.nmfs.noaa.gov/by_catch/bycatch_whatis.htm

http://content.time.com/time/health/article/0,8599,1651819,00.html

http://www.worldwildlife.org/press-releases/baiji-dolphin-previously-thought-extinct-spotted-in-the-yangtze-river

http://www.wildlifeextra.com/go/news/Yangtze-porpoise013.html#cr

 

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