Christmas Tree Worm Spawning — Caribbean Reefs
The Christmas tree worm (Spirobranchus giganteus) mass spawning event on Caribbean coral reefs — the tube-dwelling polychaete's simultaneous gamete release creating brief clouds of spawn visible as a puff of pale blue or white haze above each individual tube, thousands of individuals releasing simultaneously in the minutes after sunset following the full moon in October and November in direct response to the moonlight's signal. The Christmas tree worm's dual nature (breathtakingly beautiful spiral feeding fans visible year-round, the spawning event invisible without precise timing) creates a reef encounter where the permanent aesthetic resident reveals a completely hidden reproductive biology. At Bonaire and Curaçao's shallow fringing reefs (accessible by shore dive), the October full moon sunset snorkel produces the spawning event in water of 5 metres depth, the individual spirals' spawn visible as a cloud and the sea's surface showing a slight opalescence from the combined spawn of thousands of simultaneous individuals.
About this spectacle
In the minutes after sunset following the October or November full moon, thousands of Christmas tree worms (Spirobranchus giganteus) lining Bonaire's shallow fringing reefs release their gametes simultaneously. Each tube-dwelling polychaete ejects a brief puff of pale blue or white spawn that drifts upward from its coral home, and where thousands discharge at once, the water column fills with a delicate opalescent haze visible from the surface. The spectacle unfolds in as little as five metres of water, making it accessible to snorkellers as well as divers. For the rest of the year these same worms are simply the reef's jewels — twin spiral feeding fans in vivid reds, oranges, and blues — so the spawning event reveals an entirely hidden dimension of a resident animal most divers already admire. The precise timing window is narrow: arrive at the right reef at sunset on the full moon night and the show lasts only minutes. Missing the cue by even half an hour means missing it entirely, lending the event an almost theatrical urgency.
When to go
Oct — Nov
Getting there
Nearest airport: BON. Nearest city: Kralendijk.
Booking options
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