THE WIDELY-DISTRIBUTED INDO-PACIFIC ZOANTHID PALYTHOA TUBERCULOSA: A SEXUALLY CONSERVATIVE STRATEGIST

Here we characterize the reproductive strategy of Palythoa tuberculosa (Esper, 1791) in the northern Gulf of Aqaba. Polyp sampling revealed that P. tuberculosa is a protandrous hermaphrodite over its life cycle, but has an annual protogynous hermaphroditic cycle. Fecundity was highest in the center of the colonies, with a mean (+/- SD) of 1196 +/- 629 oocytes polyp(-1). Spawning coincided with a rise in seawater temperature, and occurred on the first week after full moon each month (June August). Gamete release and fertilization success peaked 2 d after full moon. Larvae developed into zoanthellae 13 d post-fertilization. High fecundity and long larval developmental periods suggest high investment in sexual reproduction. Nonetheless, a low recruitment was noted on the reef. Palythoa tuberculosa appears to maintain its complex reproductive strategy throughout its wide geographic distribution.