A Chinese freshwater dolphin has been declared extinct after desperate efforts to rescue it came too late.
One British zoologist today described the loss of the Yangtze River dolphin as a “shocking tragedy”.
It is the first official extinction of a large vertebrate for more than 50 years.
Experts say human activity killed off the white long-beaked dolphin, which grew to eight feet weighed up to 500 pounds.
The animal is the first cetacean, the group of mammals that includes dolphins, whales and porpoises, to vanish from Earth as a direct result of human influence.
In the 1950s the dolphin, a species unique to the Yangtze river also known as the Baiji, had a population of thousands.
Over the next five decades its numbers declined rapidly as China modernised and made heavy use of the river for fishing, transport, and electricity generation.
During Mao’s “Great Leap Forward”, traditional veneration of the Baiji - nicknamed “Goddess of the Yangtze” – was denounced and the dolphin hunted for its flesh and skin.
Industrial pollution, depleted food supplies due to overfishing, loss of habitat, and the construction of the Three Gorges Dam all put further pressure on the dolphin.
Stocks of some of its prey species collapsed to one thousandth of their pre-industrial levels.
In the crowded Yangtze, many dolphins died after becoming entangled in fishermen’s nets and being prevented from surfacing for air. Noise pollution also caused the animals, which navigate by sonar echo-location, to collide with shipping and get caught in propellers.
Surveys of the Yangtze River dolphin, Lipotes vexillifer, showed that by 2006 its population had dwindled to just 17 individuals.
Zoologists developed a scheme to save the Baiji by setting up a conservation reserve in a 21-kilometre oxbow lake which was once part of the Yangtze. The idea was to capture a few individuals and move them to the lake, where they could be cared for and bred.
But the rescue plan came too late. An intensive six week survey and search for the animals, covering the whole of their habitat range, yielded not a single one. The experts were forced to concede that the Yangtze River dolphin was extinct.
Dr Sam Turvey, from the Zoological Society of London, who led the international team which carried out the survey, said: “The loss of such a unique and charismatic species is a shocking tragedy. The Yangtze River dolphin was a remarkable mammal that separated from all other species over 20 million years ago.
“This extinction represents the disappearance of a complete branch of the evolutionary tree of life and emphasises that we have yet to take full responsibility in our role as guardians of the planet.”
Writing in the Royal Society journal Biology Letters, the scientists describe how they tried to pull the dolphin from the brink of extinction.
It is believed the main factor responsible for the Baiji’s final demise was the death of large numbers of dolphins in fishing gear.
At the start of this year, the Zoological Society of London launched EDGE, a conservation programme focusing on the world’s most Evolutionary Distinct and Globally Endangered species.
Experts calculated that of all the mammals on the EDGE list, the Yangtze River dolphin was the most threatened.
Dr Turvey added: “The Baiji’s extinction also highlights the need for new conservation initiatives in China’s increasingly threatened Yangtze ecosystem, which is also home to endangered freshwater porpoises, seven-metre long fish, giant salamanders and white Siberian cranes.”