DNA Metabarcoding Reveals the Dietary Composition for Smooth-Coated Otter (Lutrogale perspicillata) and Asian Small-Clawed Otter (Aonyx cinereus) in Malaysia

The declining population of otter species in Malaysia, including the Asian small-clawed otter (Aonyx cinereus), smooth-coated otter (Lutrogale perspicillata) and hairy-nosed otter (Lutra sumatrana), is primarily attributed to habitat changes. Understanding the ecological aspects of otters, including their diets, is crucial for formulating effective conservation management strategies. To address this knowledge gap, we employed Next Generation Sequencing (NGS) as an alternative approach to enhance our understanding of the species' food chain. Specifically, this study investigated the diets of Asian small-clawed otters and smooth-coated otters by analysing an ~130 bp segment of the Cytochrome b (Cytb) gene using Illumina Miniseq platform. The analysis successfully generated 572,311 reads, identifying four families, nine genera and 11 food species consumed by both otter species. Smooth-coated otters primarily consumed fish (96%) and frogs (4%), whereas Asian small-clawed otters exclusively fed on fish (100%), with the genus Esomus being the predominant fish genus found in the spraints. The diversity analysis of their diets revealed significant differences between two species (p < 0.05). As a result, DNA metabarcoding provides a reliable method for verifying otter dietary information and can serve as a valuable tool in assessing fish diversity, thus contributing significantly to the management and conservation of otter populations, particularly in Malaysia.