China has mitigated the impact on the conservation of the white dolphin when building a bridge across the estuary of the Pearl River. China has hailed the success of their plan to improve conservation despite constructing a bridge which might have had the opposite effect.
Conservationists were concerned that work on the world’s longest sea crossing would be disastrous for white dolphin conservation. Their conservation is of utmost importance because the population continues to decrease and they are threatened with extinction in the wild. The population is severely fragmented and there is a continuing decline of mature individuals. Probably the greatest threat to this species is incidental mortality in fishing gear. In addition, their habitat is near the coast in areas where there is a lot of human activity including exploitation of resources in the sea.
But recent information indicates that their numbers are rebounding in part because of the conservation measures taken during the construction of the bridge and partly because of a decline in shipping in one of the world’s busiest shipping areas.
The numbers are up to about 2,500 from 2,367 judging by the number of white dolphin seen in the first half of 2021. The Chinese built artificial reefs which allowed small fish and shrimp to thrive which provided a source of food for the dolphins. Also, the 34-mile bridge and tunnel network has reduced traffic in the waters which has given the dolphins a break from human activity. And thirdly, the pandemic was beneficial to them because of a reduction in human activity.
The picture is not quite so rosy in the waters around Hong Kong’s Lantau Island where it is estimated there are 37 white dolphins down from 188 in 2003, according to a survey by Hong Kong’s Department of Agriculture, Fisheries and Conservation. The study concluded that almost half of all Chinese white dolphin calves in Hong Kong waters fail to survive beyond two years of age. They become pinker with age.
Conservationists had objected to the bridge. They recommended that it should be abandoned or rerouted away from dolphins. Meng Fanchao, chief designer of the Hong Kong-Zhuhai-Macau Bridge said that as much as possible of the bridge was built on land and the number of supporting piers was cut from 318 to 224.
Comment: from my perspective, this is a rare example of China being concerned about animal welfare and conservation. They are unconcerned about introducing animal welfare laws and it appears, too, that they unconcerned or unwilling to do something about global warming. It is said that President Xi is not going to attend COP26 in Glasgow. China is responsible for 27% of global carbon emissions.
Postscript: the proper name for the Chinese white dolphin is the Indo-Pacific humpback dolphin (Sousa chinensis). The term “Chinese white dolphin” is used in mainland China, Macao, Hong Kong, Taiwan and Singapore. An adult Indo-Pacific humpback dolphin is grey, white or pink and may appear to be albino. Along the coasts of China and Thailand the dolphin has been observed with pink skin. The pink colour originates from blood vessels and not pigmentation. The blood vessels have been overdeveloped for thermoregulation.
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