From water to barcodes: DNA-based taxonomy reveals fish diversity and conservation priorities in Cambodian Lower Mekong Basin

Citation

Ghazali, Siti Zafirah and Jamaluddin, Jamsari Amirul Firdaus and Uy, Sophorn and Tith, Puthearath and Chheng, Phen and Thach, Phanara and Esa, Yuzine and Karim, Murni and Mohd Nor, Siti Azizah (2026) From water to barcodes: DNA-based taxonomy reveals fish diversity and conservation priorities in Cambodian Lower Mekong Basin. Regional Studies in Marine Science, 100. art. no. 105160. pp. 1-13. ISSN 2352-4855

Abstract

The Lower Mekong River Basin represents one of the most productive riverine ecosystems, yet comprehensive molecular assessments of its ichthyofauna remain limited. This study employed DNA barcoding to assess freshwater fish diversity along the Mekong River system in Cambodia. We obtained high-quality COI sequences from 348 specimens representing 129 morphologically identified species across 27 families and 12 orders. Cypriniformes exhibited the greatest diversity (66 species, 51.2%), followed by Siluriformes (32 species, 24.8%). Four independent molecular species delimitation methods (RESL, ASAP, GMYC, and bPTP) yielded 133–143 molecular operational taxonomic units (MOTUs) compared to 129 morphospecies. A consensus approach identified 139 MOTUs, with eight morphospecies subdivided into multiple MOTUs, indicating candidate cryptic lineages. Further integrative taxonomic studies combining molecular and morphological evidence are needed to confirm the status of candidate cryptic lineages identified in this study. Cyclocheilichthys repasson displayed the most complex structure, resolving into four distinct MOTUs. In addition, this study provided first DNA barcoding sequences for four species ( Papuligobius ocellatus , Pseudomystus siamensis , Pangio anguillaris and Syncrossus beauforti ). Conservation assessment revealed two Endangered (EN) species ( Pangasianodon hypophthalmus and Poropuntius deauratus ), eight Vulnerable (VU) species, and six Near Threatened (NT) species, highlighting the need for continued conservation efforts. This comprehensive barcode dataset provides essential baseline data for biodiversity monitoring, conservation planning, and sustainable fisheries management. The foundational reference library will enhance future environmental DNA applications and molecular-based biodiversity assessments.

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Additional Metadata

Item Type:	Article
Subject:	Ecology, Evolution, Behavior and Systematics
Subject:	Ecology
Subject:	Aquatic Science
Divisions:	International Institute of Aquaculture and Aquatic Science
DOI Number:	https://doi.org/10.1016/j.rsma.2026.105160
Publisher:	Elsevier B.V.
Keywords:	Biodiversity; Cambodia; DNA barcoding; Fish; Ichthyofauna; Mekong
Sustainable Development Goals (SDGs):	SDG 15: Life on Land, SDG 14: Life Below Water, SDG 2: Zero Hunger
Depositing User:	Ms. Siti Radziah Mohamed@mahmod
Date Deposited:	14 Jul 2026 08:58
Last Modified:	14 Jul 2026 08:58
Altmetrics:	http://www.altmetric.com/details.php?domain=psasir.upm.edu.my&doi=10.1016/j.rsma.2026.105160
URI:	http://psasir.upm.edu.my/id/eprint/126803
Statistic Details:	View Download Statistic

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