Developing quantitative PCR assays to detect threatened and invasive freshwater turtles in Hong Kong using environmental DNA

Ivan P. Y. LAM, Yik-hei SUNG, Liu LIN, Jonathan J. FONG*

*Corresponding author for this work

Research output: Journal PublicationsJournal Article (refereed)peer-review

4 Citations (Scopus)


Environmental DNA (eDNA) techniques show promise in facilitating the study and conservation of threatened species. The advantages of high sensitivity and high efficiency have been demonstrated by studies across various taxa. Asian turtles, one of the most threatened vertebrate groups, are facing extinction due to overexploitation for use as traditional Chinese medicine, food, and pets. Most species are extirpated across their ranges, but Hong Kong is unique because wild turtle populations persist. Due to the rarity and secretiveness of turtles, data on the location and size of populations are incomplete, even for a small place like Hong Kong. The result is that research and conservation are hindered. In this study, quantitative PCR eDNA assays were developed for three turtle species: two native [big-headed turtle (Platysternon megacephalum) and Chinese softshell turtle (Pelodiscus sinensis)] and one invasive [red-eared slider (Trachemys scripta elegans)]. For each assay, we tested species specificity, optimized reactions, and benchmarked analytical sensitivity for eDNA surveys. The assays will help in the conservation of Hong Kong turtles by identify priority sites for protection and research, provide another tool for population monitoring, and clarify the impact of the invasive T. s. elegans on native species.
Original languageEnglish
Pages (from-to)293-300
Number of pages8
JournalConservation Genetics Resources
Issue number2
Early online date24 May 2019
Publication statusPublished - Jun 2020

Bibliographical note

We thank Kadoorie Farm & Botanic Garden Hong Kong, Hong Kong Society of Herpetology Foundation, and Tommy Hui for providing samples. Also, we thank the following people for invaluable discussions on eDNA: Kathryn Stewart, Caren Goldberg, David Pilliod, Tracie Seimon, and Brian Horne. Lastly, we thank two anonymous reviewers for helping us improve this manuscript. This study is supported by the Research Grants Council of Hong Kong (Early Career Scheme #23100216), government of Hong Kong Special Administrative Region Environment and Conservation Fund (#ECF 2017-04), Ocean Park Conservation Foundation Conservation Fund (#RP01.1718), and the Croucher Foundation Chinese Visitorship (#870026).


  • Invasive species
  • Pelodicus sinensis
  • Platysternon megacephalum
  • TaqMan minor groove binder
  • Trachemys scripta elegans
  • Turtle conservation
  • qPCR


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