Abstract: Halophila ovalis is a dioecious seagrass species capable of both sexual reproduction and clonal propagation. This study investigated the seasonal growth and reproductive characteristics of H. ovalis population through quarterly monitoring in Zhulin, Guangxi, with particular focus on reproductive differences between female and male individuals at the center and edges of seagrass patches. Results showed that the density, coverage, and biomass of H. ovalis peaked in spring, reaching 47%±9%, (2967.36±661.96)ind.·m^-2, and (37.68±8.85)gDW·m^-2, respectively. Annual averages were 38%±14% for coverage, (1851.02±1036.81)ind.·m^-2 for shoot density, and (27.60±13.97)gDW·m^-2 for biomass. Sexual reproduction occurred in spring, with distinct female and male flowers. Both seagrass density and biomass were significantly higher at patch centers than at edges, a pattern mirrored in macrobenthic biomass. Male individuals exhibited significantly shorter internode length than females, though no significant differences were observed between center and edge positions within either sex. These findings provide fundamental insights into the reproductive ecology of H. ovalis, offering scientific support for the conservation and restoration of seagrass beds.

Key words: Halophila ovalis, seasonal variation, sexual reproduction, center-edge effect, Guangxi sea areas