More bio-diverse than our rainforests, the world’s colourful underwater reefs are a spectacle to behold.
But anyone who watched last night’s Coral Reefs episode of Blue Planet II will be aware they are currently disappearing at an alarming rate.
David Attenborough pointed out to the TV documentary’s viewers that there is a glimmer of hope, though – so long as coral reefs are able to regenerate, their future is not lost.
As confirmation that our reefs have the power to restore, a dramatic coral spawning event took place on Australia’s Great Barrier Reef last week – and experienced cameraman Stuart Ireland managed to capture his own ‘Blue Planet’ sequence on camera at Moore Reef, in the outer reef off Cairns.
Given the challenges the Great Barrier Reef has faced in recent times, with warming ocean temperatures and cyclones damaging an estimated three-quarters of the world’s largest living organisms, this event couldn’t be more poignant.
“Sexual reproduction is important for all animals, it’s a taxing time even for tiny coral polyps, but this year’s spawning may be the most important in the recent history of the Great Barrier Reef,” says marine biologist Gareth Philips.
“Coral spawning increases distribution of the corals to different areas and increases genetic resilience. This initial spawn saw high numbers of gametes released which is very positive.”
It’s a glimmer of hope indeed.
But what is coral spawning and how can you witness it?
What is it?
Taking place (usually) once a year, this mass fertilisation of corals occurs when eggs and sperm are simultaneously released into the ocean. Discovered by science only 35 years ago, relatively little is known about the remarkable event.
“Coral spawning takes us back to the rudimentary birth of the Great Barrier Reef,” says Stuart, who has filmed the phenomenon 21 times. “This is how the reef was originally created.”
When does it happen?
The event occurs around the same time time each year (October to December on the Great Barrier Reef, depending on the location), usually just after a full moon. Rising water temperatures stimulate the gametes in the adult coral, and the day length, tide height and salinity levels also play a role.
What does it look like?
Stuart describes the event as being “a bit like an upside-down snow globe”. Taking place at night, when the ocean is at its most active, the spray of silver debris can also be compared to a galaxy of shooting stars. It’s possible to snorkel by torchlight, although always go out with a guide. And make sure you shower afterwards – floating in the midst of a mass marine mating ritual won’t leave you smelling of roses.
So how can I see it?
The spawning lasts several nights but it’s always hard to pinpoint exactly when it will happen. There are predictions this year will be a split-spawning on the Great Barrier Reef, with a second event expected in early December.
For more information on the destination, visit Tourism Queensland