Epibionts are the animals or plants that colonize the surface of other organisms. Their existence can strongly affect their hosts both negatively and positively. The purpose of this study is to clarify the relationship between the host mollusk, Turbo (Lunella) coreensis, and a species-specific epiphyte, Cladophora conchopheria, and other epibionts.

Sampling was conducted at 4 different sites of boulder shore on the Magarisaki sand spit. Host shell diameter (HD) and the infestation rates of Cladophora were measured. All epibionts were identified to species and the number of individuals was recorded for each animal species.

The size of HD was significantly larger at site A (mean±SD: 22.4±2.0 mm) and smaller at site D (mean±SD: 17.2±2.8 mm). The infestation rate of Cladophora was significantly low at site A, but there was no significant difference among three other sites. Numbers of epibiotic species and zootic individuals were significantly correlated with HD, but the infestation rate of Cladophora was not significantly correlated with HD. Our study indicates that the infestation pattern of Cladophora is different from other epibionts.