Coral reproductive processes are essential for maintaining reef resilience and supporting reef restoration programs. This study investigated gametogenesis, spawning timing, fertilization success, and environmental parameters of Acropora yongei in the Bali Strait, Indonesia. Field observations were conducted from August to December 2025 at reef depths of 1–10 m, with intensive spawning monitoring focused at depths of 2–5 m. Surveys followed lunar cycles from six days before until eleven days after the full moon. Gametogenesis observations were performed using colony sampling and oocyte classification, while spawning observations were conducted through direct in situ monitoring and larval trap installation. Fertilization success was evaluated under controlled container conditions, and water quality parameters were measured simultaneously. The results showed that most Acropora spp. colonies did not exhibit synchronous spawning during the observation period. Acropora yongei was the only species consistently showing mature oocytes and spawning activity. Spawning was recorded on November 16 and 17, 2025 (D+11 and D+12 after the full moon), occurring at 19:13 and 19:22 WIB, respectively. Fertilization success increased from 32% to 36% and coincided with lower ammonia concentrations and slightly reduced temperature. These findings indicate asynchronous spawning patterns among Acropora species in the Bali Strait and highlight A. yongei as a potential operational model for coral reproductive studies and restoration strategies.
Arnenda et al. (Mon,) studied this question.