Synchronized spawning and fecundity of Acropora species in the Red Sea

The spawning season of 17 Acropora species was followed in the Egyptian Red Sea reefs. Synchronized spawning was observed for 12 of these species three nights prior to the second spring full moon in 2012 and four nights prior to the second spring full moon in 2013. Development of oocyte size and color was followed. The largest oocytes were recorded for A. clathrata (562 mu m), while the smallest recorded were from A. squarrosa (414 mu m). A significant difference in oocyte size was detected between species. Five color stages were observed during oocyte maturation: white (immature), light-cream, cream, light-pink, and pink (mature). Estimations of polyp fecundity ranged from 11 oocytes per polyp in A. formosa to 32 oocytes per polyp in A. tenuis. The fecundity of polyps varied significantly between species, while no significant differences were detected between sites, years or colonies of the same species. The density of polyps per square centimeter of tissue varied significantly between species, and ranged from 11.5 polyps/cm(2) for A. massawensis to 31 polyps/cm(2) for A. formosa. Estimated fecundity values ranged between 256 oocytes/cm(2) for A. arabensis to 627 oocytes/cm(2) for A. cytherea. The recorded changes in oocyte color and size during development could be a useful tool to predict spawning events. Improvements to our understanding of Acropora species fecundity can assist managers to develop more robust reef recovery practices to alleviate damage on reefs from natural or anthropogenic sources.