Marine researchers examining twenty coral colonies at Ningaloo Reef have discovered that key reef-building species Porites lutea and Porites lobata prepare to spawn during the annual early autumn mass spawning period.
While two of the examined species prepare to spawn in early autumn, a third species, Porites australiensis, showed no signs of reproduction during either sampling window. This suggests it may follow a completely different reproductive calendar, highlighting the necessity for year-round monitoring.
Spawning Timings and Geographic Divides
The study revealed a distinct geographic mismatch. While Ningaloo’s corals spawn in early autumn, the same species located roughly 300km further north near Dampier have been documented spawning in late spring and early summer.
Senior author Associate Professor Zoe Richards, who leads Curtin’s Coral Conservation and Research Group, noted that this separation indicates northern populations might not replenish Ningaloo if local corals are destroyed by cyclones or heatwaves, because they function as separate genetic stocks.
Implications for Coral Restoration
Timing is everything in coral restoration,
Juszkiewicz said, explaining that missing a spawning window forces teams to wait another year.
Dr Thomas Holmes, Program Manager for the WA Reef Regen Program at the Western Australian Marine Science Institution—who was not involved in the study—noted that heat stress can diminish reproduction by causing corals to produce fewer eggs and sperm for years following a major bleaching event. The research was funded by the Minderoo Exmouth Research Station, with co-authors from Curtin University Medical Research Institute, James Cook University, and The University of Western Australia.
