Genetic Variations and Expansion of the Blue Swimmer Crab (Portunus pelagicus) in Southeast Asia

Blue swimmer crabs (Portunus pelagicus) primarily inhabit the coastal regions of Southeast Asia. This study aimed to examine their population genetic structure, phylogeography, and historical demography by applying partial sequences control region in mitochondrial DNA. The analysis focused on 6 populations comprising 166 individual samples collected from Taiwan (Kezailiao Kaohsiung (KK) Penghu (PH)), mainland China (Xiamen (XM) Hong Kong (HK)), Vietnam (Hanoi (VN)), Singapore (SGP). estimated nucleotide diversity (π) for all was 0.062, with values ranging between 0.018 (PH) 0.045 (HK). Our 116 haplotypes classified them into lineages A B. XM, HK, VN, SGP made up lineage A, PH KK comprised For each lineage, results highlighted indications demographic expansion. Lineage can be traced back second-to-last interglacial period, while B possibly originated last glacial period. There were significant differences FST among six populations, except pairs HK–XM PH–KK. In conclusion, phylogeography structure P. pelagicus Asia potentially affected Pleistocene cycles human introduction. These findings further highlight possible dispersal routes throughout