Promoting larval settlement of coral Pocillopora damicornis by calcium

Larval settlement is a critical bottleneck in the process of coral sexual propagation. Promoting coral larval settlement by inducers is a promising strategy in coral reef restoration engineering. In this study, the settlement-promoting effect of Ca 2+ on larvae of the brooding coral Pocillopora damicornis was investigated for the first time. Treatment with 40 mM CaCl 2 for 24 h effectively promoted coral larval settlement (~ 80%). Moreover, CaCl 2 is comparable with the natural inducer, crustose coralline algae (CCA), in both promoting coral larval settlement and post-settlement growth. CaCl 2 showed toxic effects on larval survival and growth at high concentrations, and this could be minimized by optimizing CaCl 2 concentration and shortening the exposure period. Our study suggests that applying Ca 2+ to effectively and efficiently induce coral larval settlement is viable for laboratory research and small-scale aquaculture systems, and it might become a useful tool in future coral reef restoration engineering.