Endangered Species Handbook

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Aquatic Ecosystems

Extinct Species

 The Yangtze River (Baiji) Dolphin
    The baiji, a freshwater dolphin species weighing 220 to 355 pounds, was historically found throughout the Yangtze River and its surrounding lakes and tributaries. Like other river dolphins, they had long, narrow beaks and poor vision. Because they lived in extremely muddy waters, baiji relied on echolocation to locate mates and food. This dependence kept the ancient species alive for over 20 million years, but recently, human exploitation took its toll. The last official baiji sighting was in 2004, when only two individuals were observed. Sadly, a 2006 expedition revealed no sightings, and the species was deemed “functionally extinct.”
    The exponential growth of the Chinese population posed a variety of threats to the survival of the baiji. In 1975, the species was first listed as a Protected Animal of the First Order by the Chinese government. Chinese officials designated protected areas for the baiji; however, the areas proved insufficient and did not encompass the full length of its habitat. Futile captive breeding efforts were also attempted for years.
    In the 1990s, electrofishing killed a large number of the dolphins, and overfishing depleted their prey. Additionally, the lengthy construction of the Three Gorges Dam obstructed natural migration patterns, isolated groups of individuals, and impaired breeding opportunities. Along with this industrialization came more ship traffic, which increased the likelihood of dolphin collisions with boat propellers and ships. 
    Furthermore, the activity in the river created anthropogenic noise that impeded the baiji’s ability to locate food and mates. Water pollution and entanglement in fishing gear are also blamed for the species’ decline. The baiji, accustomed to a pristine and rich environment, was no match for the increasing pollution and congestion of its home.
    While the baiji was listed as an endangered species under the US Endangered Species Act and as a critically endangered species on the IUCN Red List of Threatened Species, it was unable to recover due to a lack of information, growing threats and its small population size. Today, the Yangtze River has lost its top predator, which will have a devastating effect on local ecosystems.

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