Daytime gamete release from the reef-building coral, Pavona sp., in the Gulf of Thailand

Abstract

[Extract] Study of the reproductive biology of reef-building corals has largely focused on patterns of synchronous spawning (e.g., Babcock et al. 1986; Baird et al. 2001; Guest et al. 2005). Multispecific, synchronous spawning usually takes place before or after the full moon in the late spring or early summer when over 105 coral species have been observed to spawn a few hours after sunset. It has been suggested that nighttime spawning avoids predation by visual feeders (Babcock et al. 1986). Nevertheless, there are coral species which have not been observed releasing gamete bundles on the predicted spawning nights. During a project to examine reproductive synchrony of reef-building corals at Rangkajew Reef in Chumphon National Park, Gulf of Thailand, we observed a "daytime" synchronous releasing of gametes from Pavona sp.