Reproductive Ecology of Coral Species

Coral reef ecosystems rely on the successful reproduction of reef-building species to maintain genetic diversity, resilience and habitat structure. Most scleractinian corals employ broadcast spawning or brooding strategies, synchronised by environmental signals such as lunar cycles, photoperiod and temperature regimes. Broadcast spawners release vast numbers of gametes in tightly timed mass events, facilitating fertilisation but remaining susceptible to disruptions in synchrony and Allee effects at low population densities. Brooders retain gametes and release competent larvae, offering local recruitment but limited dispersal. Emerging evidence highlights the sensitivity of reproductive phenology and gamete physiology to rising sea temperatures, altered light regimes and habitat fragmentation. Split spawning further modulates larval supply, enhancing connectivity but also complicating forecasts of peak spawning windows. These dynamics are critical for reef resilience under climate change, informing restoration and conservation strategies worldwide.

Research from Nature Portfolio

Recent investigations have revealed that artificial light at night can decouple coral broadcast spawning from natural lunar cues, advancing gamete release by one to three days and reducing fertilisation rates. Complementary ex situ experiments on the Hawaiian mushroom coral Lobactis scutaria have demonstrated that elevated temperatures and intensified solar radiation patterns alter spawning timing, diminish gamete quality and lower fertilisation success. Modelling of larval dispersal on coral reefs further suggests that split spawning—when colonies spawn over successive lunar months—boosts the reliability and diversity of larval supply across geographically isolated reefs, counteracting variable ocean currents and supporting population connectivity.

Reproductive Ecology of Coral Species publication trend

The graph below shows the total number of articles in reproductive ecology of coral species across all publications each year (not limited to Nature Index journals).

Technical terms

Broadcast spawning: synchronous mass release of eggs and sperm into the water column to maximise fertilisation.

Split spawning: temporal partitioning of a single spawning season over consecutive lunar months to realign reproductive events with optimal conditions.

Allee effect: decline in reproductive success at low population density due to increased distance between gamete-producing colonies.

Gametogenesis: the process by which coral oocytes and sperm develop within the polyps prior to spawning.

References

1. Global disruption of coral broadcast spawning associated with artificial light at night. Nature Communications (2023).
2. Solar radiation, temperature and the reproductive biology of the coral Lobactis scutaria in a changing climate. Scientific Reports (2023).
3. Split spawning increases robustness of coral larval supply and inter-reef connectivity. Nature Communications (2019).
4. Split spawning realigns coral reproduction with optimal environmental windows. Nature Communications (2018).
5. Allee effects limit coral fertilization success. Proceedings of the National Academy of Sciences of the United States of America (2024).
6. Repeated ex situ Spawning in Two Highly Disease Susceptible Corals in the Family Meandrinidae. Frontiers in Marine Science (2021).