Chinese White Dolphin (continued)

¡@

Life History

¡@

 Color variation

Color pattern of the Chinese White Dolphin varies at different stages of life. Dolphin babies are born in dark grey, and begin to be lighter within a few months following birth. As the dolphins become adult (about 10 years to reach adulthood), they should be pink.

Age and growth

Chinese White Dolphin is known to be able to live up to 40 years. In Hong Kong, the oldest individual known so far is 33 years old.

Reproduction

Female dolphins reach sexual maturity at the age of around 10 to 11. They give birth calves throughout a year, with slightly peaks in Spring and Summer. If the baby is alive, it'll stay with its mother for up to 3 years. Dolphin mothers won't have another baby during that time. So the rate of reproduction is quite slow.

¡@

Feeding Habitat and Behaviour

 Social organization

The Chinese White Dolphins are mostly found singly or in pairs in Hong Kong waters. But sometimes, they may occur in a larger group. The average group size is 4, and it may contain up to 23.

Behaviour

Chinese White Dolphin is very friendly and energetic. They like playing, such as breaching (jumping out of water) and spy-hopping (head bobbing), speed swimming, bowing, and tail lobbing (slapping).

Feeding habitat

Chinese White Dolphins feed mainly on fishes, especially the one small ones.  Unlike other dolphins, they don not feed on cuttlefish, octopus, shrimp and crab.

¡@

Threats to Chinese White Dolphin 

There is a trend of declining number of Chinese White Dolphins found in the Hong Kong waters.  Today, there are about a hundred dolphins, and every year an average of 10 dolphins are found dead.  It is believed that the death number could be higher than 10.

Major environmental threats to the habitats of Chinese White Dolphin include:

THREATS BASIC FACTS
(1) Large-scale infrastructural development  For example, the Chek Lap Kok International Airport involved 9.5 km2 (equivalent to near 1876 football fields) of land reclamation and over 76 million m3 of seabed dredging.  Another big project, Disney Theme Park, has been launched at Penny Bay.  It's already found that 3/4 of fish population of the area has been dead due to the human interventions.  
(2) Sewage discharge About 1.5 million tonnes of sewage is dumped daily into our harbour, with only raw treatment. It is equivalent to about 19,000 double-deck buses.  Sewage includes toxic wastes, such as cleaning fluids, bacteria and viruses, that can affect the dolphins directly, and industrial effluents, especially toxic metals, that can accumulate in sediments and be poisonous to marine life.  
(3) Over-fishing Traditional fishing practice, trawling, is destructive to the seabed habitats. In order to attain more fish gain, the fishermen are increasing the frequency of fishing and making the net hole smaller smaller. Capturing the baby fishes on seabed deters the sustainable growth of fish population.
(4) Increased shipping activities Every day, there are an average over 70 transboundary boats per hour, both passenger and cargo shipping. The fast and huge vessels are dangerous to dolphins as they can be easily hit and wounded by the vessel engines. The noisy engines also cause disturbance to dolphins.
(5) Rubbish  Rubbish can cause threat to dolphins. Like plastic bag, sometimes, the dolphins may thought that it is sea-weed and eat it. As plastic bag cannot be digested, it causes stomach problem for the dolphins

¡@

¡@

Recommended Websites:

Hong Kong DolphinWatch <http://www.zianet.com/dolphins>

World Wide Fund (Hong Kong) <http://www.wwf.org.hk>

Agriculture, Fishers and Conservation Department <http://www.info.gov.hk/afcd>

¡@