Yangtze softshell turtle losing the battle

Chlidonias · **Yangtze softshell turtle losing the battle** 07-10-2008

Bid to save world's rarest turtles fails - Telegraph

are these really the only two left in the world? Is the male really 100 years old? I'm not sure that it would be all that easy to prove that a more-or-less completely aquatic turtle is or isn't still inhabiting rivers over its range, but it looks like the Yangtze softshell is going the way of the Yangtze dolphin....

Quote:

Bid to save world's rarest turtles fails
By Malcolm Moore in Shanghai

At 80 years old, the only remaining female Yangtze giant soft-shell turtle in the world is now being kept behind bulletproof glass and is constantly monitored and guarded.

She successfully paired last spring with a 100-year-old male at Suzhou zoo in southern China.

However, the two clutches of eggs they produced did not hatch, according to Stephen Sautner at the Wildlife Conservation Society in the US.

"A number of the eggs had very thin shells, suggesting that the diet of the animals prior to breeding was not optimal," said a separate statement from the Turtle Survival Alliance.

Although more than half the eggs seemed fertile, the embryos perished before hatching.
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The pair of geriatric turtles are the only remaining Yangtze giant soft-shell turtles, or Rafetus Swinhoei. The existence of another male in Hoan Kiem Lake in the centre of Hanoi is thought to be merely a legend, while a fourth turtle, found in the wilds of North Vietnam in 2007, is now dead.

The turtles can grow up to a metre in length and weigh between 120kg and 140kg. They are distinguished by their soft green shells, their small piggish snouts and their eyes, which lie at the back of their heads.

Turtles are a symbol of health and longevity in China, but the number of Yangtze giant soft-shells has plummeted in the face of the extensive pollution of its freshwater habitats.

A survey of the country's plants and animals last year found that nearly 40 per cent of all mammal species in China are now endangered, while 70 per cent of non-flowering plants and 86 per cent of flowering species are threatened.

The two Chinese turtles are now being prepared for another round of mating this spring. The pair are being fed a high calcium diet to try to strengthen the eggs.

"We've worked very hard on this," said Liu Jinde, the director of the zoo. "We ought to succeed. The turtles are very healthy."

PAT · 07-10-2008

It is sad that there is so little of the Yangtze that is still untouched and unpolluted.
I saw in the newspaper that a scientist found this freshwater stingray that would have been at least 2 metres across.

Kifaru Bwana · 08-10-2008

Tortoises and turtles have been around for close on 210 million years. The Yangtze soft-shellted turtle pair at Suzhou Zoo have only last season been brought together. One failed breeding season does not mean the end of the battle. This was a case of desperately trying too soon.

The coming year the turtles will - in particular the female - will be better prepared with a more balanced nutrition. Last year she already produced over 100 eggs. If she does so again, the chances are much higher that the eggs have a more robust shell and also a higher chance of fertility.

In private hands quite a few endangered Cuora taxa are held. It is not unthinkable that some people might have further Yangtzes in a forgotten corner of China (after all it is a vast country).

Besides this if the next breeding season is successful the chances of bringing in the 2 male Yangtzes from Vietnam for further breeding is a real option in years to come just to diversify the gene pool a little. Inbreeding depression in reptiles is evolutionary less significant (viz their widely differing breeding techniques that include parthogenesis et al).

One lesson: hope is the start of a new vision, not a delusion for failure.
The brave are those that dare to dream beyond ... the unthinkable!

Chlidonias · 08-10-2008

here's a better article:
http://www.nytimes.com/2008/10/08/wo...turtle.html?em

Quote:

Future of Giant Turtle Still Uncertain
By JIM YARDLEY
Published: October 7, 2008
Qi Zhenglin/Wildlife Conservation Society, via Associated Press

An 80-year-old Yangtze giant soft-shell turtle, the only female known to exist, was moved in May to a zoo in Suzhou to mate with a 100-year-old male turtle. So far, no population increase.

Scientists trying to save one of the world’s most endangered species of freshwater turtles say waiting is their only recourse after a complicated attempt to mate two elderly turtles during this year’s breeding season ended without producing any offspring.

The fate of the Yangtze giant soft-shell turtle seems especially uncertain because only one female is known to exist — an 80-year-old turtle with a leathery shell that lived without notice for a half century inside a zoo in Changsha, the capital of Hunan Province, in southern China. Only when scientists discovered her existence last year did it become clear that a chance remained to save her species.

In May, scientists drove her more than 600 miles to a zoo in the city of Suzhou. There, a male turtle estimated to be 100 years old awaited her. He had been the last known male of the species, though in recent months scientists discovered two more males in Vietnam.

Gerald Kuchling, a prominent herpetologist helping to oversee the mating program, said the male and female turtles were introduced to each other on May 7.

It was a meeting that carried some risk; males can be territorial and have been known to attack other, unfamiliar, turtles. On top of that, neither turtle had seen a member of the opposite sex in decades. But scientists say the pairing was a success.

“It worked very well,” Mr. Kuchling said by telephone.

June seemed to bring good news: The female produced roughly 100 eggs and about half appeared to be fertilized. But scientists now say the embryos apparently died in early development. A recent posting on the Web site of Turtle Survival Alliance, a global network focused on protecting endangered turtles, said “a number of the eggs had very thin or cracked eggshells, suggesting that the diet of the animals prior to breeding was not optimal.”

Mr. Kuchling said the female had been fed raw beef and pork, rather than a more desirable diet of fish and crayfish.

“If the nutrition of the female is not right, then the eggs usually die,” he said.

Males of the species can reach 220 pounds, while females are usually about half that size. The female from the Changsha zoo weighs about 90 pounds, while the male from the Suzhou zoo weighs more than twice as much.

Xie Yan, the China program director for the Wildlife Conservation Society, said she remained hopeful.

She said that the diet for the female had already been changed and that her general health was considered good. The discovery of two more males is also good news, she added. “The male and the female didn’t spend enough time together this year,” she said. “This was the first time they mated. Next time will be better.”

The Yangtze giant soft-shell turtle is one of the largest freshwater species in the world, though its population has been decimated by hunting and pollution. Last year, scientists struggled to persuade either the Suzhou or the Changsha zoo to allow its turtle to be moved.

Scientists had considered artificial insemination but decided the procedure would be too risky. It became unnecessary when the Changsha zoo agreed to move the female to Suzhou.

Now, the two turtles live in adjacent ponds at the Suzhou zoo. The ponds are connected through a small channel, which is blocked by an underwater door. That door will open again next May, during breeding season, and the two old turtles will try once again.

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