Researching, regrowing and renewing the world’s coral reefs
We’re giving nature a helping hand
The Earth’s reef systems are in crisis. Mass coral destruction caused by dynamite fishing, pollution and climate change could see the majority of the planet’s coral reefs disappear within a decade. Without healthy reefs we could lose more than a million species, decimating the globe’s biodiversity and with it many industries and communities that are reliant on a healthy reef system to survive.
Marine biologist Distinguished Professor Peter Harrison and the team at Southern Cross University have developed a solution that works. A solution emerging from the seed of an idea planted four decades ago. In early springtime 1981 on Australia’s Great Barrier Reef, a small group of curious marine biology PhD researchers – among them Peter Harrison – was diving at night by torchlight. Suddenly they found themselves immersed in an amazing natural phenomenon: an underwater snowstorm of trillions of microscopic eggs and sperm being released by multiple coral species in a mass mating ritual.
From this initial observation – a worldwide scientific first – and in response to the degradation of coral reefs and associated ecosystems around the world, Coral IVF was born.
Coral IVF – the use of naturally occurring coral spawning to restore damaged reef systems – has proven to be effective for restoring breeding corals on badly damaged reefs in the Philippines, and the challenge now is to scale this success to larger reef areas including the Great Barrier Reef.
Regrowing coral reefs and effecting positive change in our natural environment
The Coral IVF team, led by Southern Cross University’s Professor Peter Harrison, has captured millions of coral sperm and eggs during synchronised sex events before rearing the larvae – sometimes turbo-charging with algae symbionts – ready to replenish heavily degraded sections of reef.
“I had the idea to capture the spawn that would otherwise drift away and end up as fish food or disintegrate without fertilising the dying reefs,” explains Professor Harrison. “We collect spawn from heat-tolerant corals that have survived bleaching, and rear millions of baby corals in specially designed tanks and coral nursery pools on the reef before delivering them onto target areas of damaged reefs to restore and repopulate them.”
Divers use fine mesh nets to capture the microscopic eggs and sperm that float to the surface. The spawn is then placed in floating enclosures where they grow for up to a week before reseeding the baby corals (larvae) onto damaged reefs.
This methodology builds on the enormous success of Professor Harrison’s earlier work with then Southern Cross University PhD candidate Dexter dela Cruz and other researchers from the Philippines, restoring reef areas degraded by dynamite fishing. Working with our Pacific neighbour since 2012, Professor Harrison says research shows re-seeded corals can grow to “dinner plate-sized adult colonies within three years and they were able to sexually reproduce at this age”.
There is great promise in the mass larval restoration approach as it has the potential to make a difference to reef recovery on a global scale. The success of this research shows that where the natural supply of larvae has been compromised, damaged coral populations can be restored and repaired using millions of coral larvae settled on these reefs.
This is what we are doing
Coral researchers are working day and night on the Great Barrier Reef to complete a radically new approach to mass coral re-seeding, rearing millions of hardy coral babies in the days after the Great Barrier Reef’s annual mass spawning event.
This coral larval restoration project at Heron Island and One Tree Island is a very large and complex undertaking.
What we're doing during this program is combining the expertise of my team from Southern Cross University, colleagues from CSIRO and from Queensland University of Technology and together we're exploring ways to make the operations of the Coral IVF program more efficient so that within the next few years we can get to much larger scales.
Working on the Great Barrier Reef is like a dream for every marine biologist especially those working with corals so I'm so happy about that. Every trip that I do where I'm culturing larvae I learn something better about how to culture them differently or how to make this process better, more efficient.
What we've done during the past week is capture some spawn from the major coral spawning events here at Heron Island and One Tree Island. We've lost so many large breeding corals that the natural production cycle of millions of larvae has started to diminish.
The Coral Larval Restoration experiment shows that if you add larvae to those damaged reef areas you can kickstart the recovery of the coral community. It helps restore the ecosystems around Australia, around the world. It also helps restore fish populations which a lot of indigenous communities rely on especially around the tropical regions and the South Sea Islander regions as well.
I hadn't seen the larval restoration sites for a couple of years so there was a great sense of anticipation when we went for the dive and I was thrilled to see so many healthy, new corals growing on the experimental sites where we placed larvae in 2016. That outcome re-energised me personally and professionally because it shows that the Larval Restoration process does work and now we need to take these results and scale it to much larger scales within the next few years so we can actively restore coral communities on damaged areas of the Great Barrier Reef so we can start to reverse the trend of declining corals.
Whitsundays tourism industry onboard to deliver new life to damaged reefs
The Whitsundays is piloting a tourism-led restoration of the Great Barrier Reef, working alongside Southern Cross University and the Australian Institute of Marine Science to scale-up Coral IVF.
In a world-first trial around Hook Island, Whitsunday tourism operators, vessel owners and the community collected coral spawn from the ocean’s surface during the annual spawning event and placed it in specially modified larvae nursery pools.