29 Apr 2019

Mass coral spawning 2019

Singapore's corals are alive and very sexy too. Their annual orgy of explosive sex just happened! Thanks to the dedicated team who have been keeping an eye on this event every year, we get a glimpse of what happened.

What is Mass Coral Spawning and why is it a big deal? More below!

What is Mass Coral spawning?

Once a year, on the fourth month, around four days after the full moon, our corals seed the seas with new life!

Some corals release their eggs and sperm all the same time. Called broadcast spawners, these mass spawning events usually occur once a year, a few nights after full moon.

Tiny packets of eggs and sperm pop out of the coral polyps.

These packets drift to the water surface where they open up, releasing the eggs and sperm for fertilization.

After a few days, the embryos will have developed into coral larvae that drift about and eventually settle down on a hard surface to form new corals.

While bazillions of eggs and sperms are released during a mass spawn, most don't make it. Hordes of marine creatures gorge on the spawn, from fishes and crabs to jellyfishes.

As the tiny coral larvae develop, they have to survive the countless predators that constantly sieve the water for plankton and edible bits.

The coral larvae also have to overcome many other challenges that we are still learning about. Excessive sedimentation, for example, can interfere with fertilisation and other aspects of coral larvae survival and successful settlement.

Other marine creatures may also join in and spawn too. Like this Barrel sponge.

Why is mass coral spawning in Singapore a big deal?
From Sex in the Tropics 2008 on the blooooooooooo blog

Coral mass spawning in Singapore was first recorded by Dr James Guest in 2002. It was the first record of coral spawning in the tropics. At least 18 different coral species from ten genera and five families (Acroporidae, Faviidae, Merulinidae, Oculinidae and Pectiniidae) have been observed to spawn in our waters! Mass spawning occurs on the third to fifth nights after the full moon between 8 and 10 p.m.


In interviews with the media, Dr James Guest emphasised that corals are part of Singapore's biodiversity and natural heritage. "There are 255 species of corals recorded here, and there may be some corals here that were around before Stamford Raffles arrived."

The fact that our corals mass spawn shows that our reefs are functioning well! According to Dr James, the number of coral species in Singapore that mass spawn is "as high as on other Indo-Pacific reefs, like the Great Barrier Reef... " This shows how rich Singapore's natural heritage is. We can find right at our doorstep: "diverse, functional and fascinating coral reefs, that people would normally associate only with countries like Australia."

MORE photos of Mass Coral Spawning in 2019

Chay Hoon on 25 Apr at Raffles Lighthouse


Lisa Lim at Raffles Lighthouse


Previous posts about previous coral spawning

This post first appeared on the wild shores of singapore blog.

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