Chelonian Conservation and Biology: Surveying for Swinhoe’s Softshell Turtle

In recent years, the Swinhoei’s softshell turtle (Rafetus swinhoei) has risen to fame in part because of its renown as the rarest freshwater turtle in the world (there are only four Swinhoe’s softshell turtles known to exist in the wild or captivity today), not to mention its prominent role as the famed Sword Lake Turtle of Vietnamese legend. Writing in the July 2013 issue of Chelonian Conservation and Biology, a team of Chinese researchers published the results of a four-year survey of villagers living along the Upper Red River, China, to determine the historical distribution of the Swinhoe’s softshell turtle and characterize suitable habitat where conservation efforts should be focused.

Following previous investigations that have narrowed the historical range of the species to the Song Hong (Red River) drainage in eastern China and northern Vietnam, the lower Yangtze (Yangtze River) drainage in eastern China, and the Song Ma (Ma River) drainage in northern Vietnam, the researchers concentrated their survey effort within the Upper Red River, where the present-day range of this giant softshell turtle is thought to be restricted today. Through questionnaires and oral interviews, which included testing interviewees’ abilities to positively identify local turtle species, the researchers canvassed more than 1,000 college students, fishery and wildlife managers, fishermen, turtle farmers, traders, restaurant keepers, and education/government officials across 38 counties, 3 provinces, and 82 communities (from towns to villages).

In general, the researchers found that the younger respondents (i.e. college students) knew little of any giant softshell turtles, while Dai/Thai villagers along the Red River and its tributaries had longer memories of a turtle they called either dao or wu gui (“black hardshell turtle”) or hua tou mei (“spotted head turtle”), all of which were positively identified as Swinhoe’s softshell turtles based on careful descriptions of the turtles and the inspection of skeletal remains. Following the intense pressures of commercial fisheries for softshell turtles in the region, by the late 1990s, specimens tentatively identified from photographs as Swinhoei’s softshell turtles caught using rolling-hook and electroshock fishing had become increasingly rare.

Through a comparison of habitat characteristics between the 33 documented capture/witness locations and 33 random contrasting plots using Google Earth, the researchers were able to characterize those characteristics that appeared to favor Swinhoe’s softshell turtle presence. These features include sandbars, necessary for basking and nesting, and tributary/main river confluences, which provide abundant food and create deep water as well as sandbars. The researchers also addressed the influence dams may have on surviving indivuals, citing the deleterious effects of reduced flows, habitat and population fragmentation, anomalous floods, lower water temperatures, and sandbar degradation. Sadly, the researchers note that of the 33 capture/witness locations, 29 are subject to flood following the erection of five dams slated for construction. The remaining four sites are at the mercy of a sixth proposed dam that, if constructed, could remove the last remaining high priority habitat suitable for Swinhoe’s softshell turtle.

Full Citation: Wang Jian, Shi Hai-Tao, Wen Cheng, and Han Lian-Xian. 2013. Habitat Selection and Conservation Suggestions for the Yangtze Giant Softshell Turtle (Rafetus swinhoei) in the Upper Red River, China. Chelonian Conservation and Biology: July 2013, Vol. 12, No. 1, pp. 177-184.

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