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The World's Greatest Sex Show

Step right up everybody. Come to Cairns, Australia and the Great Barrier Reef for the world's greatest sex show, on selected evenings into December.

The first of 2023 took place on the full moon a few days ago.

It's coral spawning time on The Great Barrier Reef.

So what does this "Spawn Show" involve exactly?

Billions of tiny pink balls explode into the water as different species of soft corals and a handful of hard corals began the regeneration process, spawning for a few hours during the night. The sex cell bundles break open releasing sperm and eggs to bump into each other as they float on the Coral Sea currents and then settle on coral rubble to form baby corals. “Right now, the Great Barrier Reef is teeming with new life," says ”Great Barrier Reef Foundation Managing Director Anna Marsden.

“The annual coral spawning is not only one of the most extraordinary natural phenomena on the planet, it provides us with an opportunity to fast-track world-leading research to safeguard its future from the impacts of climate change,” she said.

What is coral spawning? Coral spawning is the reef having sex. Coral polyps simultaneously release egg and sperm bundles into the ocean for external fertilisation. This happens in an annual mass event earning it the cheeky reputation of being the world’s largest orgasm on the world’s largest organism. During this time the Great Barrier Reef is transformed into an underwater spectacle resembling the inside of a snow globe. The spawn creates a pink-brown slick on the surface where the sperm will meet a compatible egg and produce a larvae that takes about ten days to fully mature into a coral polyp. Stories passed down by coastal Indigenous communities acknowledge coral spawning, but western science did not become aware of it until 1982 so researchers are still learning about the phenomenon. Inshore reefs tend to spawn a month ahead of the outer reef where the spawning is more spectacular. It generally occurs on the outer reefs off Cairns and Port Douglas two to six nights after the November full moon when water temperatures are 27-28C. This year the full moon is at the end of the month in both October and November and may result in a split spawn after both moons. There is little movement of the water between high and low tides in the week following the full moon and these calm conditions help to maximise the fertilisation process. Spawning predominantly occurs at night when the plankton-eating reef fish are sleeping which reduces the risk of the eggs being eaten.

How to see the coral spawning

If you're keen to get among it - literally, some tour operators offer coral spawning night trips in November and December 2023. Diver’s Den, Pro Dive Cairns and Tusa) Liveaboards are also out on the Great Barrier Reef during coral spawning. It’s a natural event so seeing the coral spawning is not guaranteed, but you will still spend your evening discovering the sea creatures that emerge after dark.

Pic: Calypso Productions


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