In Search of the Rarest Turtles in the World
Affected Species: the Yangtze softshell turtle (Rafetus swinhoei)
Location: Vietnam (Hanoi)
The Yangtze Softshell Turtle is one of the largest, if not the largest, freshwater turtle in the world. Today, we know of only three living specimens: one pair in China, and in Vietnam one specimen in which the gender is still unknown. Sadly, the female in China, known as “China Girl,” has been producing infertile eggs for years. Thus, Turtle Island will focus on finding additional specimens in the wild, and we will do everything possible to preserve this mysterious species from extinction.
TURTLE ISLAND has made it one of its main objectives to prevent the final disappearance of this impressive turtle.
The Yangtze Softshell Turtle was described in 1873 by John Edward Gray, based on a juvenile specimen. In subsequent years, this remarkable species was seen as synonymous with the Chinese Softshell Turtle (Pelodiscus sinensis). Thus, it was not recognized as a separate species until Peter Meylan, 1987, revalidated Rafetus swinhoei in his morphological studies. For a long time, the Yangtze Softshell Turtle remained a mystery to science; nothing was known about its biology or ecology. Thanks to the pioneering work of the famous turtle specialist, Peter Pritchard, the mystery around the Yangtze Softshell Turtle was solved, and the species came into public spotlight. At that time, some R. swinhoei were still kept as show animals in Chinese zoos, and one resided in a botanical garden. For years, Chinese zoos kept softshell turtles in large outdoor ponds. As zoos modernized, the turtles were transferred to indoor exhibits, where most met with an early demise.
Today, only three specimens of R. swinhoei are known to science. Thanks to the commitment of Dr. Gerald Kuchling, the only verified female from the Changsha Zoo in Hunan, China was paired with the only known Chinese male in Suzhou Zoo. Despite numerous egg deposits from “China Girl,” (up to 200 eggs in three clutches per year) not a single egg has hatched. With a test that stains the egg membrane to locate attached sperm, a method commonly used for bird eggs, Kaitlyn Croyle from the San Diego Zoo tested “China Girl’s” eggs and was unable to detect any sperm heads. Thus, infertility may be due to either a male mechanical problem or male sterility. The first variant could be bridged with artificial insemination.
The only known specimen outside of China lives in Vietnam. A very old, huge male lived in the vibrant city center of Hanoi, the capital of Vietnam. This legendary turtle was considered to be an official sanctum in Vietnam and was even worshiped as a god. Every student knows the legend of the hero Le Loi, who as a poor fisherman, was presented a golden sword from a golden turtle. Invincible with this magical sword, Le Loi in fierce combat sent the Chinese troops of the Ming Dynasty to flight (1418-1428) and liberated Vietnam. According to legend, the sword was taken from him again by the golden turtle and is today located at the bottom of the lake. On an island in the center of the Hoan Kiem Lake in the Ngoc Son Temple, a deceased Yangtze Softshell Turtle is exhibited in a showcase and is admired by thousands of tourists. In 2011, this huge, old 170 kg male was found to be in a critical state of health. He was safely trapped, successfully treated and was released back into the lake in June of the same year. Unfortunatly the massive turtle died in January 2016 and reduced the known world population to three specimens.
In 2007, the only surviving specimen from Vietnam was discovered by the Asian Turtle Program (ATP) in Dong Mo Lake, located about two hours from Hanoi. Local fishermen tell of one or even two additional Yangtze Softshell Turtles in the lake, but they have yet to be confirmed. Dong Mo Lake is separated by a dam with locks from the adjacent Red River. During floods in the rainy season, these locks are opened; and in 2008, the softshell turtle managed to escape into the river. A few kilometers downstream, the Dong Mo softshell was caught in a net of a local fisherman. Due to excellent cooperation among local communities, the ATP team was informed immediately. The Forest Protection Department (FPD) in conjunction with the Education for Nature Vietnam (ENV) negotiated the challenging purchase of this valuable turtle so that it could be released back into Dong Mo Lake. There are divided opinions about this turtle’s sex. In the near future, we will try to capture the Dong Mo turtle to determine the sex by using ultrasound scans, obtain tissue samples for cryopreservation and the promising environmental (e-DNA) method.
With the help of e-DNA, tiny DNA fragments derived from metabolic processes or skin residues can be detected in water samples. This method has already been established for fish and amphibians, but has barely been tested on turtles. We hope to use this technology to confirm the presence or absence of R. swinhoei in lakes where survey crews have indicated a potential specimen.
In Yunnan, the team, associated with Prof. Rao from the Kunming University and Dr. Gerald R. Kuchling, has located a R. swinhoei in a 20 km-long river section between two dams of the Red River. Unfortunately, this important softshell turtle has yet to be trapped and is at high risk of being caught and eaten by fishermen.
Since 2003, numerous field surveys have been performed in Vietnam to find additional specimens. Now these efforts will be multiplied due to international funding from various sources. In 2013, Turtle Island began participating in the surveys and has combed through sections of rivers and wetlands in Vietnam and northeastern Laos. In Laos, the team encountered a pond where a Yangtze softshell turtle had lived for 45 years until the summer of 2013, when during a monsoon flood, it migrated into the adjacent river and has not been seen since.
With only three known individuals, this spectacular turtle is one of the rarest species in the world and is listed by the International Union for the Conservation of Nature (IUCN) and the Zoological Society of London (ZSL) among the top 100 most endangered life forms.
TURTLE ISLAND has made it one of its main objectives to prevent the final disappearance of this impressive turtle. In summer of 2015, a team will again travel to Vietnam and Laos in search of the surviving Yangtze Softshell Turtles.