The world’s largest coral reef system, the Great Barrier Reef, is currently experiencing one of the most spectacular events to occur on the reef, is the annual synchronised spawning of corals.
Likened to an underwater fireworks display, the spectacular display is proof of the future, the development of the next generation and hope for the reef.
Coral spawning really is the biggest reproduction show on Earth, but what exactly is it and how does IVF help?
What is coral spawning?
This mass reproduction only happens once a year, where colonies and species of coral polyps simultaneously releasing tiny egg and sperm bundles from their gut cavity into the water. By expelling the eggs and sperm at the same time, the coral increases the likelihood that fertilisation will take place.
The spawning lasts between a few days and a week as different species release their eggs and sperm on different days to prevent hybrids from being produced.
A series of events need to align for this to happen, after a full moon and only after rising water temperatures have stimulated the maturation of the gametes within the adult coral. The day length, tide height and salinity levels also appear to be factors in deciding when the event will happen.
The phenomenon — which only happens at night — resembles an underwater snowstorm. But rather than being all white, there are also clouds of red, yellow and orange. All the bundles rise slowly to the surface where the process of fertilisation begins.
While spawning takes place on a large scale, it doesn’t happen across the entire Reef all at once. Instead, the time of year that corals spawn depends on their location. Those on inshore reefs usually start spawning one to six nights after the first full moon in October, whereas those in outer reefs spawn during November or December.
The mass spawning also provides ready food for other marine creatures, particularly nocturnal animals such as plankton and some fish species.
How is Coral IVF helping?
The Great Barrier Reef is composed of over 2,900 individual reefs and 900 islands stretching for over 2,300 kilometres over an area of approximately 344,400 square kilometres. That is a lot of area to cover, so sometimes nature needs a little assistance.
This is where Coral IVF comes in and helps boost the process. The Great Barrier Reef Foundation’s upscaling of the Coral IVF technique means reef restoration on the Great Barrier Reef will reach ‘kilometre scale’.
After seeing the potential of this game-changing technique, the Foundation brought Coral IVF to the Great Barrier Reef in 2016, and since then the Foundation and its researchers have successfully pioneered and evolved the technique to restore and repair damaged coral populations.
Right now, the Great Barrier Reef Foundation is significantly scaling up Coral IVF. By bringing together researchers with community partners and tourism operators on the Reef, they are upskilling and training them on this technique to go forth and restore damaged reefs at scale across multiple reef sites.
Great Barrier Reef Foundation Managing Director Anna Marsden said “Coral spawning is an incredible event that only happens once a year and that’s why we pioneered Coral IVF back in 2016 with our researchers to give nature a helping hand.
“It truly is inspirational and proves what can be achieved by bringing people and science together to save our irreplaceable Reef and its marine life. Right now, the Great Barrier Reef Foundation is scaling up Coral IVF by bringing together our researchers, the local community and tourism operators to restore and repair damaged coral populations.”Great Barrier Reef Foundation Managing Director Anna Marsden
Last summer, the Great Barrier Reef suffered its third mass bleaching – the third in the last five years. This is the reality of living in a world where the impact of climate change affects our Reef, and the annual event of mass coral spawning is now not enough to replace the corals lost.
Coral IVF is the first project of its kind to re-establish coral breeding populations on damaged reefs. Great Barrier Reef Foundation researchers are giving nature a helping hand by collecting millions of coral eggs and sperm during the spawning season, growing them into baby coral and releasing them onto degraded areas of the Reef.
It is just one technique that is being investigated as part of the world’s largest coral reefs program, which sees the Foundation bringing together the best minds and technologies to investigate new techniques to restore coral reefs and adapt them at unprecedented scales.
Led by the Great Barrier Reef Foundation’s coral ‘sexpert’ Professor Peter Harrison, coral IVF has captured the world’s attention, and rightly so. Peter’s work on the GBR builds on the enormous success of earlier studies in the Philippines, where hectares of degraded coral reefs have been restored thanks to the technique.
Lead researcher and Southern Cross University Professor Peter Harrison said, “The Coral IVF technique consists of capturing coral eggs and sperm from heat tolerant corals that have survived bleaching, and rear millions of baby corals in specially-designed nursery pools, before delivering them onto target areas of damaged reefs to restore and repopulate them.
“The baby corals settle onto those reefs and in a few years, they will grow to dinner plate size and beyond at which point they’ll sexually reproduce and create their own coral babies – re-establishing the breeding populations on damaged reefs.”Southern Cross University Professor Peter Harrison
Ways to get involved with reef restoration
Volunteering with Reef Restoration Foundation will provide you with a once in a lifetime opportunity to play an active role in our pioneering ocean-based coral nurseries on the Great Barrier Reef!
Volunteers are vital to the work undertaken by Reef Restoration Foundation. Our volunteers are motivated, passionate and an inspiring bunch of amazing people who are committed to making a positive difference to the Great Barrier Reef.