5 CONCLUSIONS
In this study, we present the first exploration of the genetic structure of L. spadiceus in the SCS. The mtDNA sequence analysis of specimens from the SCS revealed no significant genetic differentiation among sampling sites, with low F st values indicating genetic homogeneity, which probably reflected widespread and recent historical interconnections during the post-glaciation. Hainan Island and Leizhou Peninsula had no effect on gene flow of L. spadiceus in the SCS. In its demographic history, it experienced a low effective population size during the Quaternary period that increased sharply after the last glacial maximum (LGM). The phylogeographic pattern of L. spadiceus may be attributed to past population expansion and long-distance larval dispersal facilitated by present-day ocean currents. Given the maternally inherited characteristics of mtDNA, which cannot accurately provide the overall population structure. To gain a better understanding of the population structure of L. spadiceus , further investigation using more precise nuclear genetic markers like microsatellites and single nucleotide polymorphisms is needed. These markers would help determine more accurate and refined management units, which can then inform the development of an effective management policy.