Chasing The World’s Rarest Turtle (Yangtze Giant Softshell, Rafetuus swinhoei) - via Herp Digest

By Brent Crane, December 24, 2018, The New Yorker

A few months ago, on a sunny afternoon in northern Vietnam, I set off in a small fishing boat outfitted with a motorbike engine to find the world’s most endangered turtle. Of the planet’s four known remaining Yangtze giant softshells (Rafetus swinhoei), only two reside in the wild. Both occupy separate lakes in northern Vietnam. The other two, the world’s sole surviving couple, live in a zoo in southern China; for years, scientists have been trying to breed them, unsuccessfully. (The male has a damaged penis.) The two wild turtles represent the final hope for the species. I had boarded the boat hoping to glimpse one of them in Dong Mo, a fourteen-hundred-hectare lake an hour or so west of Hanoi. I was joined by a group of Vietnamese conservationists allied with the Asian Turtle Program (A.T.P.) of Indo-Myanmar Conservation, a U.K.-registered nonprofit organization. The odds were against us.

The Yangtze giant softshell occupies a regal position in national lore. Legend has it that, in the fifteenth century, in a Hanoi lake called Hoan Kiem, the turtle was the keeper of a mythic sword used to liberate the country from Chinese invaders. Sightings are said to bring good fortune. In 2016, when Hoan Kiem’s sole softshell—which was nicknamed Cu Rua, or “great-grandfather turtle” in Vietnamese—was found dead, it made international news. (Politically, it was bad timing: some joked that its death, which came on the eve of an important gathering of the Vietnamese Communist Party, signalled the regime’s demise.) The country mourned. “It was like losing part of our culture,” Hoang Van Ha, an A.T.P. conservationist, told me.

The turtle in Dong Mo is estimated to be forty or fifty years old, which is considered quite young. For the past eleven years, A.T.P. volunteers have been doing near-daily patrols on the lake, keeping an eye on the turtle and observing its behavioral patterns. The species lives up to its name, with individuals growing to more than three hundred and sixty pounds. Though it used to be common in the region, a combination of hunting, environmental degradation, and rampant development has brought it to the existential brink. Dong Mo’s patrollers usually witness the reptile only once every few weeks, Ha told me, but observers had seen it surface several times in the hours before I arrived. It was the first clear day in weeks, and the turtle was basking.

Dong Mo is a soupy-brown color, and the lake is filled with bamboo-choked isles. It was formed in the seventies, when a dam was built on the Red River, the major waterway of northern Vietnam. Scientists think that the Dong Mo turtle was trapped there after the river’s damming.

(Historically, the turtle has lived in large rivers and channels.) 

Conservation-wise, this was a blessing. “If this animal were out in the Red River, there would be nothing we could do to monitor it or give it protection,” Tim McCormack, an A.T.P. program coördinator, told me. In 2008, heavy rains caused the dam to overflow. The turtle escaped, but only into a fisherman’s net. It took six hours of negotiation between N.G.O. volunteers, the police, local cadres, and the fisherman to rescue the animal. In 2013, conservationists successfully lobbied for a law that fully protects the turtle from capture or sale.

Since then, other safeguards have been installed. On Dong Mo, the A.T.P. conservationists showed me a mesh net, sixty-five feet deep, that was laid across a portion of the lake to prevent escapes. I asked if they ever worried that the turtle would become entangled. “Normally, when he encounters the net, it just swims away,” Ha said. The conservationists lifted the net out of the water and tossed caught branches to the side. Nguyen Tai Thang, a conservationist wearing a pith helmet, repaired a hole with some rope. The turtle was nowhere in sight.

Though the giant softshell’s future appears grim, there have been a few inspiring developments of late. In April, the existence of the second wild specimen was confirmed in a lake called Xuan Khanh. The discovery was made using a new method known as environmental DNA, or eDNA, which reveals the presence of animals by genetically analyzing water samples. eDNA could be used to confirm other softshell specimens across Asia.

Genetics are also coming in handy elsewhere. Last year, a paper published in Scientific Reports showed that, contrary to prior understanding, softshell turtles possess sex chromosomes, which means that they can be sexed using DNA analysis. Minh Le, an evolutionary biologist at Vietnam National University and a research associate at the American Museum of Natural History, told me that preparations were already being made for a test on the Dong Mo turtle. (DNA samples were procured during its escape and capture in 2008.) Assuming things go smoothly, they should have results early next year.

The sex of the two Vietnamese turtles will determine the next course of action. If both are male, plans may be made to transfer either a whole turtle or semen samples to the Suzhou Zoo, in southern China, where the only known female lives. In July, the Suzhou Zoo made a formal appeal to the Vietnamese government to do just this, but no decision has been made. Since 2008, the zoo has been trying to get its pair to produce offspring, but the male’s member, mutilated in a battle with another male some decades ago, produces shoddy sperm. (The other male died in the fight.) It is also very old, likely over a century, Gerald Kuchling, an Austrian turtle biologist who has overseen the Chinese breeding program since the early two-thousands, said.

Artificial insemination has been attempted three times on the Suzhou pair, but no eggs have hatched. If conservationists can change that, population numbers could rebound rapidly. “It only takes a couple of years of breeding success and there could be hundreds of individuals,” McCormack told me. But even hatchlings present new problems: when the population comes from the same family, inbreeding becomes an issue. Moreover, all of the structural problems that decimated the turtles in the first place persist. Dams continue to be built along southeast Asian rivers, wetlands are being developed, and demand for turtle meat still tempts hunters.

Perhaps Dong Mo can serve as an example of local conservation success. Through negotiation with land managers, the A.T.P. was able to create a no-fishing zone within two portions of the lake, giving the turtle its own hunting grounds. The organization has also educated local communities about the turtle. Conservationists give lectures at schools, hang up flyers in villages, and even host the Turtle Football Cup, an annual soccer tournament on the banks of Dong Mo. Winners get a large poster of the turtle.

First artificial insemination of Yangtze giant softshell turtle

Date: May 27, 2015

Source: ResearchSEA

Summary: A female Yangtze giant softshell turtle (Rafetus swinhoei) -- potentially the last female of her species -- has been artificially inseminated. The procedure, which brought together top scientists from China, Australia and the United States, provides a ray of hope in a continuing effort to save the world's most endangered turtle.

Continued ...

World's Largest Freshwater Turtle Nearly Extinct- The last known pair of Yangtze giant softshell turtles mated again in June. - via Herp Digest

Kaitlin Solimine, National Geographic, July 1, 2013

The fate of a species is resting on the shells of two turtles at China's Suzhou Zoo.

In June, researchers collected eggs from the last mating pair of the critically endangered Yangtze giant softshell turtle (Rafetus swinhoei) in the hopes that at least one will be fertile.

The 220-pound (100-kilogram) freshwater giant, which spends most of its life burrowing in mud, was once common in its namesake Yangtze River, China's Lake Taihu and Yunnan Province, and parts of Vietnam.

By the late 1990s, however, human encroachment and poaching for use of the shells in Chinese traditional medicine rapidly depleted the population. Now, a total of four animals are known—two wild males in Vietnam and the mating pair at Suzhou Zoo.

It's the team's sixth year of breeding the turtles at the zoo, which is not far from Shanghai. So far, none of the eggs have hatched.

Researchers can't pinpoint the reason for the infertility, but they suspect a combination of factors, including poor sperm quality due to the male's age—roughly a hundred—an improper mating posture, and stress on the female.

Because the turtles are the last in captivity and too much human interaction could kill them, sperm samples cannot be taken nor tests run. Still, scientists are hoping that this year will be the lucky one. (Related: "Pictures: Turtles Hunted, Traded, Squeezed Out of Their Habitats.")

"The resurrection of this iconic species in the wild, the largest freshwater turtle in the world, would be a symbol of hope," said Gerald Kuchling, founder of the Australia-based group Turtle Conservancy and a turtle-reproduction expert.

"Miraculous" Find

As is the case with many near-extinct species, by the time scientists realized the extent of the turtle's decline, the species was almost gone.

In 2006, the U.S. nonprofit Turtle Survival Alliance asked Kuchling to establish the sex of the last three captive giant softshell turtles in China, which at the time lived at the Shanghai Zoo, Suzhou Zoo, and Suzhou's West Garden Buddhist Temple. (Related: "6 of Nature's Loneliest Animals Looking for Love.")

When Kuchling landed in China in 2007, the Shanghai Zoo and Buddhist Temple individuals had already died. The Suzhou Zoo male was the last known Chinese survivor. Researchers sent an all-points bulletin to every zoo in the nation in the off chance a turtle had been misidentified.

Their call was answered: A photograph of a turtle at the Changsha Zoo looked promising. Kuchling, along with Lu Shunqing, China director for the Wildlife Conservation Society, traveled to Changsha, where they confirmed it was a Yangtze giant softshell—and a female to boot.

"It's a bit miraculous we found her," said Emily King, the Suzhou Zoo breeding program's field assistant.

Breeding Roadblocks

Although moving the Changsha Zoo's female—the younger of the pair at then 80 years old—to the Suzhou Zoo was risky because of the stress it would cause the animal, zoo officials and researchers had no choice.

Surveys in the wild consistently had turned up no Yangtze giant softshells aside from the two males already known in Vietnam. These individuals haven't been captured because catching and transporting them could be fatal.

Either the Suzhou Zoo pair would mate, or the species would go extinct.

In May 2008, after much red tape, the female finally arrived in Suzhou. Just over a week later, the turtles mated-despite the fact that the female had likely never met a male. (Also see "Mating Turtles Fossilized in the Act.")

A month later, the female laid her first clutch of 45 eggs on the zoo enclosure's beach, 32 of which were incubated.

To determine if an egg is fertile, the scientists candle them, or hold a candle behind the egg to look for a developing embryo.

The initial batch yielded no hatchlings. Later that month, a second batch was equally infertile.

The turtles mated each of the following years, but with the same result.

Di Min, a zoologist at the Suzhou Zoo, said when the program started there was talk about assisted reproductive techniques, a kind of "turtle IVF."

"But the best and safest is they breed naturally. There's only this pair—if we lose one, especially the female, we don't have any chance."

The team doesn't know how much longer the zoo turtles will live or continue to mate, but scientists suspect Yangtze giant softshells can live well over a hundred years.

Turtle Team Optimistic

Despite these setbacks, scientists are staying optimistic about saving the turtle.

"We have these two [Suzhou] animals, and hopefully in the very near future, as opposed to far distant, we'll have baby Rafetuses on our hands," added field assistant King.

"In one shape or another, the program will go on, because everyone is invested in having this species continue."