Baiji (Lipotes vexillifer)
Critically endangered on the IUCN Red List (possibly extinct).
Lipotes vexillifer is probably the most endangered cetacean, and may already be extinct. It lives only in the Yangtze River in China, where they feed on freshwater fish. It lives in small groups of three or four dolphins, although group sizes can reach up to sixteen individuals. It has been sighted swimming with finless porpoises (Neophocaena phocaenoides), which also live in the Yangtze River.
The Yangtze River is one of the busiest stretches of water in the world, which has put much pressure on L. vexillifer. A recent threat is the use of electricity for fishing, which has caused 40% of deaths of this species in recent years. Some also become caught in fishing equipment, and the entire river ecosystem is poisoned by pesticides and pollution.
L. vexillifer has been a protected species since 1975, but this did not help stop the decline in numbers. Five Baiji Semi-Natural Reserves were created in 1992 and it was planned that all wild individuals would be relocated to these areas. Unfortunately, catching the dolphins was extremely difficult, and those that were captured only survived for a few months. There have been no sightings since 2004, and this species may already be extinct.