Cellular and Biochemical Changes in Early Embryonic Development of a Scleractinian Coral,<i> Fimbriaphyllia (Euphyllia) ancora</i>

Abstract

Knowledge of early life histories of scleractinian corals is essential for ecological studies (e.g., larval dispersion and connectivity) and development of aquaculture techniques. The present study documents cellular and biochemical changes during early development of a scleractinian coral, Fimbriaphyllia ancora (Order Scleractinia, Family Euphyllidae). Observations of spawning revealed that F. ancora releases positively buoyant eggs. No fertilization membrane surrounded fertilized eggs, which developed into swimming planula larvae within 48 h after fertilization. Lipid content analysis showed that eggs are rich in wax esters, and that the wax ester concentration decreases significantly in planulae. Sugar content analysis revealed that the eggs are also rich in glycogen, and that the glycogen concentration increases as development progresses. Free glucose was not detected in samples that we analyzed. Moreover, a settlement assay showed that F. ancora planulae prefer to settle on dead coral debris, compared to other substrate materials, such as plastic, microscope slides, ceramics, and crustose coralline algae.