Mass coral spawning in Rumassala Marine Sanctuary: March inter-monsoon lunar triggers?

Synchronized mass coral spawning in southern Sri Lanka occurs during the March/April inter-monsoon when sea surface temperatures stabilize around 29.5-30.5°C and ocean swell calms. Spawning is triggered by the full moon, occurring three to six nights after the lunar peak between 8:30 PM and 11:00 PM. Acropora and Porites colonies release pink egg-and-sperm bundles simultaneously in an extraordinary blizzard of gametes that float to the surface, overwhelming planktivorous reef predators and maximizing cross-fertilization before currents disperse larvae.