Sexual reproduction of a low-temperature tolerant coral Oulastrea crispata (Scleractinia, Faviidae) in Hong Kong, China

Abstract

In December 1993, an experimental artificial reef made of pulverised fuel ash (PFA) and concrete was deployed at Hoi Ha Wan Marine Park, Hong Kong. The reproductive biology of Oulastrea crispata, the pioneer species recruited onto the structure, was studied to ascertain its reproductive strategies, including its gametogenic cycle in terms of oocyte and spermary development and timing of planula release. A histological study showed that O. crispata was hermaphroditic and had an annual gametogenic cycle with an extended spawning period from July to October. Planulae were released in the resting period of the gametogenic cycle. With an opportunist life history trait, including a wide range of reproductive strategies, O. crispata is able to colonize a variety of substrata, including those unfavourable to other corals, and to flourish as the pioneer colonizer of newly immersed structures.