Environmental DNA and Traditional Approaches for Fish Diversity Assessment in Mesangat Ilir, East Kalimantan, Indonesia

Traditional fish capture methods often provide incomplete data, particularly for species inhabiting hard-to-access environments. Environmental DNA (eDNA) metabarcoding offers a sensitive and non-invasive alternative for species detection. This study integrated traditional morphological surveys and eDNA analysis to obtain a more comprehensive assessment of fish diversity in the Mesangat Ilir River, East Kalimantan. eDNA metabarcoding detected six species, five of which overlapped with the 19 species captured by traditional methods, and one additional species (Trichopsis vittata) that was not captured. Based on the combined results of both methods, the family Cyprinidae was dominant (12 species; 60), followed by Bagridae and Osphronemidae, each represented by two species (10). Additionally, Cobitidae, Anabantidae, Helostomatidae, and Pristolepidae were each represented by a single species (5). Therefore, integrating eDNA with traditional surveys is recommended to support long-term conservation strategies for endemic, threatened, and vulnerable freshwater species. ©2026 The authors.