Gametogenesis and Inter-annual Variability in the Spawning Pattern of Acropora hyacinthus in Northwestern Philippines.

Emmeline A. Jamodiong, Elizaldy A. Maboloc, Ronald D. Villanueva, and Patrick C. Cabaitan (2018) Acropora hyacinthus is a fast-growing tabular coral that dominates the shallow water coral assemblage in the Magsaysay reef at the Bolinao-Anda Reef Complex (BARC), northwestern Philippines. The timing of gamete development was investigated for A. hyacinthus through dissection and histological analyses of coral fragments that were collected monthly from February 2014 to April 2015 from the 22 tagged colonies. The spawning time was identified by the presence of oocytes in the sampled A. hyacinthus colonies through rapid sampling from January to March 2014, 2015 and 2016. Results show that A. hyacinthus is a hermaphroditic broadcast spawning coral with an annual gametogenic cycle. Acropora hyacinthus exhibits an extended release of gametes across 2 to 3 months, from February to April. Major release of gametes occurred in March. Two types of extended spawning patterns that are unique in this region were observed in this species (i.e., asynchronous spawning amongst colonies and split spawning of individual colonies). This study contributes to the increasing knowledge on the coral reproductive strategies in northwestern Philippines and provides information on availability of coral materials for coral reef restoration efforts and management.