Broadcast Spawning
Corals releasing eggs and sperm simultaneously into the water column, where fertilization occurs. A mass reproductive event timed to environmental cues.
A reproductive strategy in which corals release eggs and sperm into the water column at the same time, allowing fertilization to occur in the open ocean rather than internally. This synchronized mass spawning event typically occurs once or twice yearly, triggered by environmental cues like water temperature and lunar cycles, and requires sufficient population density for successful fertilization.
What this means in real life
On a single night each year, thousands of coral colonies on a reef simultaneously release clouds of eggs and sperm into the water. The ocean becomes milky with reproductive material, and currents carry sperm to eggs from neighboring colonies, creating new coral larvae that drift and settle elsewhere.
What it isn’t
This is not asexual reproduction or fragmentation—it involves genetic recombination from two parents. It's also not a continuous process; it happens in synchronized, predictable pulses rather than year-round.
Commonly misused online
Often conflated with 'coral spawning' generally, which can include asexual reproduction. Some posts treat it as a rare emergency event, when it's actually a normal, predictable annual cycle essential to reef health.