Giant clam shells provide a solid substrate for various species of epibionts. Yet, it is not well known how epibiont communities vary among populations of different giant clam species and in giant clams restocked in different habitat types. Here, we examined differences in the epibiont communities of three species of giant clams with different shell morphology (Tridacna gigas, Tridacna derasa, and Hippopus hippopus), and characterized the epibiont communities on T. gigas from three different habitat types (sandy reef flat, seagrass bed, and coral reef). Tridacna gigas had higher species richness, abundance, and cover of epibionts compared to the other two species. Tridacna gigas in coral reef habitat also displayed higher species richness and cover of sessile epibionts, while the same species in the sandy reef flat had higher species richness and abundance of mobile epibionts. Epibiont communities were more variable across habitat types than among different giant clam species restocked in a similar area. Differences in abundance of Trochus sp., Pyramidella sp., and crustose coralline algae contributed to the variability in epibiont communities among the giant clam species and across habitats. A few taxa were observed only on specific giant clam species and sites. For instance, Diadema sp. and Echinometra sp. were found only on T. gigas, and Diadema sp. was present only in the sandy reef flat. Both the complexity of the giant clam shells and habitat type contribute to differences in associated epibiont communities. This further emphasizes the ecological importance of giant clams as habitats for other invertebrates.

巨型蛤壳为各种表生物提供了坚实的基质。然而，目前尚不清楚不同巨蛤物种种群以及在不同栖息地类型中放养的巨蛤的表生物群落如何变化。在这里，我们研究了三种具有不同贝壳形态的砗磲（砗磲、砗磲和河马）的表生物群落差异，并对来自三种不同生境类型（沙礁滩、海草床和珊瑚礁）。与其他两个物种相比，砗磲的物种丰富度、丰度和表生物覆盖度更高。砗磲在珊瑚礁栖息地中也表现出较高的物种丰富度和固着表生物覆盖度，而沙礁滩中的相同物种则具有较高的物种丰富度和移动表生物丰度。表生物群落在不同栖息地类型之间的变化比在相似区域放养的不同巨蛤物种之间的变化更大。Trochus sp.、Pyramidella sp. 和壳状珊瑚藻的丰度差异导致了巨蛤物种和不同栖息地表生物群落的变异。仅在特定的巨蛤物种和地点观察到一些类群。例如，Diadema sp。和Echinometra sp。仅在T. gigas和Diadema上发现sp。仅存在于沙质礁滩中。巨蛤壳的复杂性和栖息地类型都导致了相关表生物群落的差异。这进一步强调了巨蛤作为其他无脊椎动物栖息地的生态重要性。