As of today, peak season now, through ~July 31. Earth Exhibit tracks the live conditions and flags it the moment it is on.
On a sandy reef flat in Palau, the world's largest known spawning aggregation of bumphead parrotfish gathers month after month.
These are the giants of the reef — up to 1.3 meters long, armored with a steep bony forehead and a beak that grinds coral to sand.
Drawn by the new moon, more than a thousand of them mass over the reef before dawn, the big males jostling and head-butting in clouds of churned water, then rising together in spiraling rushes to release eggs and milt into the current.
The water fills with spawning bursts and the deep concussion of bumpheads colliding.
The same Palau reefs stage a second spectacle on the opposite lunar phase: around the full moon, thousands of red and twin-spot snapper pile up in dense, swirling towers before they too spawn, and the channel's resident sharks come in to hunt the throng.
Witnessing it means an early, current-swept dive timed precisely to the moon — but few reef events match the sheer biomass.
Where to see it
A taste of where to see it. The full map, exact coordinates and the best timing for each spot live in the app.
| Viewing spots |
|---|
| Ulong Channel & Adjacent Reef Passes |
This is the short version
This page shows a taste. The app has the full list of where to see this, the exact timing, and live conditions for 1,000+ natural phenomena worldwide, so you know the moment one is genuinely worth the trip.