Spawning of Acropora digitifera in an aquarium as recorded by continuous interval photography using an underwater camera

An advanced underwater camera was used for recording coral spawning at a flow-through seawater aquarium. A colony of Acropora digitifera from the reef flat of Sesoko Island, Okinawa, Japan was transferred to a flow-through aquarium and photographed continuously for 5 days at 10 min intervals using an underwater digital camera equipped with a lens wiper. LED lighting was provided. The number of gamete bundle-like particles between the coral and seawater surface was counted on the photographs obtained. The gamete bundle release started around 22:00 pm on 31 May, 2015 (2 h and 50 min after sunset and 3 days before full moon). Spawning was estimated to continue for < 2 hours. The present study indicates that an underwater camera with a lens wiper system will help elucidate the details of coral spawning.