Title
An Interview-Based Survey to Investigate the Occurrence of Swinhoe's Giant Softshell Turtle (Rafetus swinhoei) in Huaphanh Province of Northern Lao PDR
Author(s)
Steven G. Platt; Phia Moua Valeetyiayee; Anong Thoyar; Jay C. White; Lonnie D. McCaskill
Published
2023
Abstract
Swinhoe’s Giant Softshell Turtle (Rafetus swinhoei) is considered the most critically endangered chelonian in the world. A combination of chronic over-harvesting, wetland destruction, construction of hydropower dams, widespread water pollution, and the development, sedimentation, and flooding of riverside sandbanks (critical nesting habitat) has pushed R. swinhoei to the brink of extinction. The current global population, including captive individuals and unconfirmed reports of wild turtles, is thought to consist of 10-20 adults, although this figure is could be significantly inflated as most reports of Rafetus swinhoei remain unconfirmed. With Rafetus swinhoei now tottering at the edge of the extinction abyss, finding new individuals in the wild is critical for the survival of this species. To this end, we conducted an interview-based survey in villages along the Xam, Et, and Ma rivers in Huaphanh Province of northern Lao PDR during March-April 2023. We interviewed 251 people in 49 towns and villages along the Et, Ma and Xam rivers during our survey. Our interview data indicates that a species of large softshell turtle – most likely Rafetus swinhoei – formerly occurred in the Xam and Ma Rivers. The most recent credible reports date to the 1990s and early 2000s (last reported in 2007), although the majority of encounters occurred prior to 1990. Without additional corroborating evidence, more recent literature reports from Laos cannot be accepted as credible. Given the lack of recent credible reports, coupled with widespread and intense harvesting pressure, we consider it near-certain that R. swinhoei has been extirpated in the Xam and Ma rivers within Laos. We attribute the extirpation of R. swinhoei in Laos to chronic over-harvesting (both targeted and opportunistic) of turtles. Although we cannot rule out the possibility that one or two R. swinhoei survive in the Xam or Ma Rivers, the ability of a large softshell turtle to remain undetected in a landscape of high human occupancy is doubtful. Our survey also documented the occurrence of Palea steindachneri (Critically Endangered) in the region, complementing a single earlier record from Huaphanh Province. Local ecological knowledge obtained during our interviews adds significantly to our understanding of the reproductive biology of P. steindachneri. Our survey also confirmed that softshell turtles are subject to ongoing, intense harvesting pressure, largely as a result of opportunistic capture incidental to fishing. Without exception, those persons we interviewed stated that softshell turtles were significantly more abundant in the past, suggesting widespread population declines have occurred. Population declines of softshell turtles (and other wildlife) are probably being driven by unchecked, transboundary wildlife trafficking in which wildlife harvested in Laos is illegally smuggled into Vietnam. We conclude by recommending continued survey effort on rivers and reservoirs of the Red River Drainage in northern Laos in hopes of locating surviving R. swinhoei.
Full Citation
Platt, S.G., P.M. Valeetyiayee, A. Thoyar, J.C. White, and L.D. McCaskill (2023). An Interview-Based Survey to Investigate the Occurrence of Swinhoe's Giant Softshell Turtle (Rafetus swinhoei) in Huaphanh Province of Northern Lao PDR. Vientiane, Lao PDR: Wildlife Conservation Society, Lao PDR.
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