Abstract:
There have been great quantity of studies in many aspects on coral sexual reproduction, but only few studies on duration and period of reproduction have been explored. Hence, this research was gained to investigate spawning duration and period of Acropora nobilis and Pocillopora verrucosa; and to analyze the relationship among colonies size, duration and period of spawning and number of mature egg per polyp slice. Divings were made at night to record spawning duration and period directly through one moon cycle. The number of mature egg per polyp slice was determined by histological approach. The results showed that spawning corals occurred at the full and dark moon. In the dark moon phase, spawning duration of A. nobilis has longer time (83–142 min) and significantly different to P. verrucosa (75–110 min). However, there were no difference of spawning period between species found (A. nobilis: 2-3 nights; P. verrucosa: 1-3 nights). The relationship among colony diameter to duration and period of spawning and number of mature egg were revealed a significant polynomial. This relatonship showed explicitly that there was a decreasing duration and period of spawning as well as number of mature egg in bigger colony size (elder colony) after passing the reproductive size or age.
