---Baiji or Yangtze river dolphin

The Baiji lives in the Yangtze river in China. This species is the most endangered species of all whales and dolphins. In the 6,300 km stretch of the Yangtze river probably less than 200 dolphins occur. There has never been an active hunt for the Baiji. However, an increase in fishing activity in the river has resulted in a higher accidental capture rate in fishing gear. Also, habitat changes, such
as the building of dams and irrigation works, has affected the fish population and thus the food supply for the Baiji.

In recent years, boat traffic on the river has increased considerably, resulting in disturbance of the dolphins and an increase in injuries and deaths because of collisions with ship propellers. Together with the Giant Panda, the Baiji is the focus of widely supported conservation programs in China. Most attention is now focussed on the reduction of unnatural mortality.

---Blue whale

The blue whale is the largest whale species (indeed the largest animal that ever lived on Earth). When the right whale declined, modern whalers turned their attention to the blue whale, being the largest fin whale or rorqual species. Between 1924 and 1971, at least 230,000 blue whale have been caught. As a result, the populations of this species declined rapidly. In the 1950s, the International Whaling Commission (IWC) became concerned about the blue whale but it was not until 1964 that an agreement to stop taking blue whales was reached.

The North Atlantic population has dropped from 10-15,000 to about 500, the North Pacific population from 5,000 to 1,400-1,900 and the Antarctic population from160-240,000 to about 6,500. Some of the North Atlantic sub-populations seem to be recovering. For other populations, there are no obvious trends.

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---Bottlenose dolphin

In other areas, such as the Eastern Tropical Pacific Ocean, bottlenose dolphins get entangled in fishing gear (approximately 4-500 per year). Also, there is still a direct hunt for bottlenose dolphins in Japan, which takes a few hundred dolphins each year.

---Ganges river dolphin

The Ganges river dolphin (also called the Ganges susu) is threatened by destruction of their habitat. In the Ganges irrigation works and dams for hydro-electric plants have been constructed, limiting their range. In addition, the susu is often entangled and drowned in fishing gear.

The river is also heavily polluted in several areas, due to raw sewage dumping and industrial waste. The levels of organo-chlorines and heavy metals in the dolphins is comparable to those found in marine dolphin species. In the past, these animals have also been hunted for their flesh and blubber. In 1982, the total population of Ganges river dolphins was estimated to be 4,000-5,000 animals. There are no recent estimates available.

---Harbour porpoise

This small porpoise (1.4-1.9m) can be found in temperate coastal waters all over the northern hemisphere. As a species, the harbour porpoise is not endangered, but in several areas, the harbour
porpoise is threatened because of high levels of accidental captures in fishing gear, especially in the North Atlantic. In the North Sea, an estimated 3.1% of the total population is killed in fishing gear each year and this level of bycatch is considered a threat to the population: it will cause the population to decline rapidly. In the Danish fisheries alone, about 4,700 porpoises are caught each year and the total population in that area is estimated at about 150,000 animals.

In the 1940s, harbour porpoises were a rather common sight on the Finnish coast of the Baltic Sea. From the 1960 to the 1990s, no harbour porpoises have been reported in Finnish waters at all. The most likely cause was the high level of pollution of the Baltic, specifically with DTT and PCBs. These pollutants had affected the harbour porpoises' reproductive system. However, in October 1990, a group of 10 porpoises has been seen near Kotka, on the South Finland coast.

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---Northern right whale

The Northern right whale has been heavily hunted in the past. The whalers considered this species the right whale to hunt, because it floated when killed. As a result, this species was the main focus of early whaling, until the population collapsed to such a low level, that hunting it became uneconomical.

Nowadays, this species is protected, but it does not seem to recover. This may be caused by an increase in disturbance by ships and offshore oil platforms. The North Atlantic population currently
numbers in the low hundreds. The North Pacific population is very small (less than 100) and is believed to be near extinction.

---River dolphins

Most dolphin species live in the sea. However, one group of dolphins, the family Platanistidae or river dolphins, lives mainly in the fresh water of rivers. There are five species of river dolphins:

· the Amazon river dolphin or Boto
· the Baiji or Yangtze river dolphin
· the franciscana
· the Ganges river dolphin
· the Indus river dolphin

The rivers are often difficult places to live for dolphins. The available space is relatively small. Many rivers are polluted by industrial waste water or by run-off water from the surrounding agricultural areas. Also, there is a large fishing industry in some rivers. With this in mind, it is not surprising that the river dolphins are among the most endangered dolphin species.

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