Moonrise timing is key for synchronized spawning in coral Dipsastraea speciosa

Significance Mass coral spawning is a perplexing annual event that occurs over a few nights following a full moon. This paper demonstrates that the period of darkness between sunset and moonrise that occurs after the full moon is a trigger for spawning in coral species Dipsastraea speciosa . As this species shares similar spawning patterns with many other coral taxa, we expect this model for spawning to be applicable to other coral species. Our discovery provides insights into how coral spawning is synchronized via the lunar cycle.