Palau spawning dive guide - when to visit

Amongst seasoned scuba divers, Palau is regarded as a very special dive destination. From the country’s spectacular karst scenery and determined commitment to conservation, to its shark-patrolled drifts and stunning shipwrecks, there are myriad reasons why divers love the islands of Palau. Not least, the extraordinary spawning events that can be reliably witnessed throughout the year.

This small Pacific Ocean nation has become a hotspot for divers determined to experience these fleeting spawning phenomenons. Like anything involving nature, luck still plays its part. But, local guides and captains have become skilled at predicting the exact time and place that particular spawning events occur.

In this article, we draw on our dive travel experts’ personal experience to highlight some of Palau’s iconic spawning spectacles, the species involved, and the factors that play a part in their predictability – helping you understand exactly what experiences are on offer here, and when to visit for the very best chances.

• Palau’s spawning events often occur around the new and full moons
• The moon cycle influences tides, currents, light, and more
• Different species favour different conditions for spawning

Palau’s spawning events are intimately linked to the lunar cycle, with both fish and coral species spawning at different phases – especially during the new and full moons. The gravitational pull of the moon is at its strongest at these times of the month, creating larger tides and stronger currents, which help to disperse fertilised eggs far and wide. Nutrients and oxygen carried by the currents can also be beneficial to the eggs and will ultimately provide a vital lifeline for the larvae once hatched.

The spawning species may also respond to changes in the amount of light produced by the moon throughout its cycle, preferring to aggregate either under the cover of darkness or beneath the dappled moonlight, depending on the species. Similarly, the time of day is another useful factor in predicting when spawning might occur, with many species tending to spawn at dawn or dusk, when light is low, in order to minimise the threat of predators.

In Palau, bohar snapper and bumphead parrotfish spawning aggregations occur every month, around the full and new moons respectively. The predictable nature of these events means that they are the most common spawning dives offered, with a very good chance of witnessing the spectacle if you opt to dive with an experienced operator. 

• Between five and ten thousand gathering monthly
• Dives typically conducted at dawn in the open ocean
• Chance of oceanic blacktips and bull sharks

Palau’s bohar snapper spawn monthly, making it one of the more regular and reliable dive experiences. Also known as twin-spot snapper or red snapper, these fish begin to aggregate in their thousands during the days leading up to the full moon, with anywhere between five and ten thousand individuals gathering around deep coral reefs. Dives are often conducted in open ocean, where groups will enter the water and await the snappers’ appearance.

At the break of dawn, once the tide begins to shift, this huge school rises from the reef and bursts into the blue, releasing white clouds of gametes into the water column as the fish writhe amongst one another. The fish then return to the reef before rising into the blue once more, repeating the sequence again and again for up to an hour. And, with the spectacle occurring over several days before climaxing around the full moon, you’ve got a good chance of witnessing this chaotic yet captivating performance.

As you’d expect from an event such as this, the bohar snapper are usually accompanied by an entourage of eager predators. Aside from other snapper species feasting on the eggs, it is also possible to spot numerous oceanic blacktips and bull sharks prowling the edges of the exhibition, attacking the preoccupied school at opportune moments. 

• A couple of thousand gathering each month
• Dives typically conducted at dawn above the reef
• Possible to hear the booming sound of males butting heads

Like the bohar snapper, Palau’s bumphead parrotfish also spawn monthly – though, this time, around the new moon phase of the lunar cycle. The bumphead parrotfish tend to gather closer to the reeftop, in slightly shallower water, but currents can still be powerful, making it difficult for divers to keep sight of the frenzied fish. And, while these aggregations are fewer in numbers, likely averaging around a couple of thousand, the impressive size of these fish – which can reach lengths of more than a metre – make the entire event even more exhilarating.

Again, this spawning display occurs in the early morning, starting as a small throng of fish before growing in size and ramping up in energy as the ideal conditions come together. As the anticipation increases, the fish begin displaying beautiful bands and bars of colour, a hint to the explosive firework display to come. At any moment, the first female will make her move, propelling herself towards the surface, followed closely by multiple males and trailed by a stream of gametes. Once the fertilisation is complete, the plume of parrotfish sinks swiftly back amongst the main school, giving way to the next group. Over the next half an hour or so, more and more fish begin to burst forth like firecrackers, filling the surrounding waters with gametes until it is milky with millions of fertilised eggs.

As these spawning aggregations occur closer to the reef, they attract fewer bull sharks, but plenty of sizable reef sharks can be seen patrolling to and fro. As the bumphead parrotfish prepare to spawn, it is also possible to hear the thunderous cracks of males fighting like buffaloes to gain superiority.

There are several other remarkable spawning events that can be experienced around Palau. But, while equally impressive, these events are far less frequent and a little harder to predict, requiring more effort and preparation to witness.

• Occurs between the months of June and August
• Hundreds if not thousands of camouflage groupers
• Blacktips, whitetips, grey reef sharks, and sickle-fin lemon sharks

The spawning of camouflage grouper in Palau occurs just once a year, during the new moon period sometime between the months of June and August. In the days leading up to the new moon, hundreds if not thousands of camouflage groupers congregate around specific reef passages of Palau, hunkering down amongst the corals until their time to shine. As currents and tides combine to create the optimum conditions, and the day gives way to darkness, the groupers emerge from their hiding places and spiral towards the surface in pairs, releasing their gametes in unison. As the spectacle progresses, countless pairs begin shooting towards the surface to spawn, stalked by sharp-eyed predators including black and whitetip reef sharks, grey reef sharks, and sickle-fin lemon sharks. 

• Occurs during the months March, April and sometimes May
• Gatherings of up to 50,000 sailfin snapper
• Pack themselves into a tight ball as protection against sharks

During the months of March, April and occasionally May, sailfin snapper rise from their deepwater dwelling to spawn amongst the shallow sites of Palau. These events can see up to 50,000 individual sailfin snapper gather in a single spot, making it one of Palau’s largest recorded spawning aggregations to date. Also known as blue-lined sea bream, these fish prefer to spawn around the new moon, waiting for the right combination of time and tide. Having gathered patiently in preparation, the snapper will move to an area with sufficient current to spawn, packing themselves into a tight ball for protection against bull sharks, lemon sharks, and blacktips. 

• Occurs during the months of January and February
• Large groups gather on the outer reefs
• Exact location and timings are harder to guarantee

Large groups of both Moorish idols and orange-spine unicornfish gather on Palau’s outer reefs during the months of January and February. Usually seen in small groups, these fish begin aggregating around the half moon period and remain in schools until the full moon. The exact location and timings of these spawning events are harder to guarantee, though some operators do offer trips.