Effect of Substratum Structural Complexity of Coral Seedlings on the Settlement and Post-Settlement Survivorship of Coral Settlers

The substratum structure is critical for facilitating settlement and increasing the survivorship of coral settlers. However, knowledge about its structural complexity largely lacking. In this study, we examined effect on post-settlement settlers using four types structures: groove, a CSD (Coral Settlement Device, 4.5 cm φ × 2.5 H, top-shaped ceramic); flat, CP (Ceramic Plate, 29.5 L 3.1 W 0.9 unglazed ceramic plate); linear, CN Net, mesh size 19 mm, biodegradable plastic net); wrinkle, SS (Scallop Shell, 11.0 in shell length). was obtained from ratio surface area to vertically projected substratum. sets were installed reef around Ryukyu Islands every May 2012 2014. After 2 or 6 months spawning, certain number sampled, spats that settled them counted by taxa classified into Acropora, Pocilloporidae, Millepora, Others. larval rate first set samples second estimated. mean was, order, CSD; SS; CN; CP, CP; CN, over three years. A positive correlation found between complexity, rate, survivorship. Our results show seedlings affects larvae spats.