Palau’s bumphead parrotfish (green humphead parrotfish, Bolbometopon muricatum) spawning aggregations are a recent discovery.
Palauan fishermen knew that bumphead parrotfish were gathering on a section of the reef and sleeping in the shallows for several nights after the new moon.
Yet it wasn't until 2010, that a Japanese dive operator discovered, on early morning dives in the area, that the bumpheads were actually group spawning outside the same reef every month, a few days before the new moon...
This was news not only for Palau, but also for the scientific community, since it was assumed, based on observations, that bumphead parrotfish engaged only in pair spawning. In these mass-spawning events, bumphead parrotfish first gather near the reef, in the shallows.
The excitement builds up as the tide switches to outgoing (falling): their bumps, cheeks and tails turn white, and stripes appear across their bodies.
The fish then gather deeper, with males head-butting each other, probably competing for mating privileges, after which the actual spawning begins.
Groups of frantic males chase the females up to the shallows, where they release white clouds of reproductive cells in the water like fireworks…
The spawning continues for roughly 30 minutes to an hour, peaking before the excitement dies down.
These spawning events happen every month in Palau, just before the new moon, and aggregations can range from a few hundred to ten thousand individuals, depending on seasonal conditions.
Music: “Castles in the Sky” by Scott Buckley – www.scottbuckley.com.au - licenced under a Creative Commons (CC BY 3.0) license
Shot on a Panasonic Lumix LX10 (LX9/LX15), Inon UWL-H100, Magic Filter, Nauticam housing
Palauan fishermen knew that bumphead parrotfish were gathering on a section of the reef and sleeping in the shallows for several nights after the new moon.
Yet it wasn't until 2010, that a Japanese dive operator discovered, on early morning dives in the area, that the bumpheads were actually group spawning outside the same reef every month, a few days before the new moon...
This was news not only for Palau, but also for the scientific community, since it was assumed, based on observations, that bumphead parrotfish engaged only in pair spawning. In these mass-spawning events, bumphead parrotfish first gather near the reef, in the shallows.
The excitement builds up as the tide switches to outgoing (falling): their bumps, cheeks and tails turn white, and stripes appear across their bodies.
The fish then gather deeper, with males head-butting each other, probably competing for mating privileges, after which the actual spawning begins.
Groups of frantic males chase the females up to the shallows, where they release white clouds of reproductive cells in the water like fireworks…
The spawning continues for roughly 30 minutes to an hour, peaking before the excitement dies down.
These spawning events happen every month in Palau, just before the new moon, and aggregations can range from a few hundred to ten thousand individuals, depending on seasonal conditions.
Music: “Castles in the Sky” by Scott Buckley – www.scottbuckley.com.au - licenced under a Creative Commons (CC BY 3.0) license Shot on a Panasonic Lumix LX10 (LX9/LX15), Inon UWL-H100, Magic Filter, Nauticam housing 
