Phylogeography and DNA Barcode Characterization of Nile Tilapia ( Oreochromis niloticus Linnaeus, 1758) in Several Asia Waters with the New Sequences Record from the Singkil Peat Swamp in Aceh Province, Indonesia

Abstract This research bridges a key phylogeographic gap for Nile tilapia ( Oreochromis niloticus ) in Asia by presenting pioneering DNA barcode data from Indonesia’s Singkil Peat Swamp ecosystem. We obtained partial cytochrome c oxidase subunit I (COI) one sequences from Singkil and complemented them with GenBank data from Bangladesh, China, India, Indonesia, Israel, Malaysia, Philippines, Qatar, Thailand, and Vietnam. Analysis of 67 sequences (639 bp) revealed high genetic diversity (haplotype diversity Hd = 0.933; nucleotide diversity π = 0.03232) with 22 identified haplotypes. Phylogenetic reconstruction identified three well-supported subclades: Subclade I (Indonesia, Vietnam, Malaysia, Philippines, Qatar, Thailand, Israel), Subclade II (Bangladesh, India), and Subclade III (exclusively China). This structure, corroborated by haplotype networks, reflects a complex invasion history driven by human aquaculture transfers rather than natural dispersal. The findings provide crucial genetic evidence for managing O. niloticus as distinct invasive lineages across Asia, with implications for biosecurity and conservation planning in biodiverse regions like Southeast Asia. These results provide crucial baseline data for monitoring spread and implementing targeted management strategies for this economically important yet invasive species.