Baiji -The Chinese River Dolphin

Baiji is a fresh water dolphin and one of the most endangered species on Earth. It is pale blue to gray on the back (dorsal) side and white on the belly (ventral) side. It has a long beak which is slightly up-turned and it has 31-36 conical teeth on both jaw. Baiji has a low and triangular dorsal fin and it resembles of a light-colored flag when the dolphin swims just below the surface of the dark Yangtze river. It has smaller eyes compared to oceanic dolphins. Baiji dolphin weighs about 220kg and is about 2.5m long.

Baiji came to attention of the western world in 1916 but it has been described in classical Chinese literature much earlier. 

Baiji is thought to breed in the beginning of the year between February and April. A baby Baiji is about 1m long. Baiji dolphins live approximately 25 years. 

There is not much known about Baiji dolphins behavior, ecology and acoustics. Most commonly dolphins live in groups of 2-6 but also bigger groups with 16 members have been seen. Dolphins feed on large variety of fresh water fish species. Beiji dolphins are generally shy of boats and only top of their head or dorsal fin are shown when surfacing. 

Like many other dolphin species, Baiji produces two kind of sounds; clicks and whistles. Baijis use clicking noise mostly for navigation and identifying a pray or other objects in the environment. Whistles are thought to be used in communication and the pitch of the whistles change. 

The Chinese river dolphin is found only in fresh water and mostly in Yangtze river. The biggest threat for Baijis are local fishers who use rolling hooks, nets and electro-fishing. In 1970s and 1980s rolling hooks and other fishing gears caused at leas half of all dolphins deaths. In 1990s electro-fishing killed about 40% of the specie.
Other threats are for example pollution, river development projects, and underwater explosions.

Chinese government started to protect Baiji dolphins from extinction by setting laws and making organisations. Also in The United States Baijis are protected among many other marine species.

In 2006 an international research team made a six weeks survey to find and examine Baiji dolphins. By the end of the experiment the group failed to find any signs of the specie and concluded that the Chinese river dolphin may now be extinct.

References: http://www.fisheries.noaa.gov/pr/species/mammals/dolphins/chinese-river-dolphin.html