IVF FOR THE REEF

But fortunately for the Great Barrier Reef, there are many brilliant minds working on ways to protect its coral for future generations, whether that’s through cryopreserving coral sperm or coral genomics sequencing, where scientists are studying genetic differences in corals to understand why some types are better equipped to withstand heat stress.

Harrison is at the forefront of the innovation. He is currently six years into a larval restoration project that’s working to capture and rear millions of coral larvae produced during the annual spawning and re-settle them on degraded reefs to rapidly re-establish new corals – like coral IVF on a massive scale.

“We started the project in 2013 when we put millions of microscopic larvae on the reef system, and they’ve grown into very large size corals. Over three years they reached dinner-plate size, were sexually reproductive and started spawning,” Harrison said, proudly.

He now has 14 out of 14 successful experiments under his belt, where the larvae have not only settled, grown and, in some cases, started reproducing, but with much higher settlement rates compared to in the natural environment, where currents and tides can wash away much of the larvae. He’s quietly confident that this project could play a huge part in saving both the Great Barrier Reef and other reefs around the world.

Initially, Harrison was capturing coral spawn manually, rearing them in ‘fertility clinics’ – either small, floating ponds on the reef or back in the lab – for five to six days, depending on the temperature, until the larvae were ready to settle and be put back out on the reef. However, he needed to scale up, and a fortuitous meeting in 2018 with Matt Dunbabin, chief investigator with the Australian Centre for Robotic Vision at Queensland University of Technology, gave him the opportunity he needed.

Dunbabin is the creator of the world’s first underwater robotic system, relying solely on robotic vision, that’s designed specifically for coral reef environments. He was initially using it to seek out and inject crown-of-thorns starfish with poisonous bile salts, in hope of culling their ever-increasing numbers. However, after talking with Harrison, he adapted his drone to both deliver coral larvae onto the reefs – almost like an underwater crop duster – and use AI to learn the optimum spots for reseeding.

The results were spectacular: at a coral spawning event in the Philippines in April 2019, Harrison and Dunbabin were able to reseed three 1-hectare areas of reef, which had been decimated by blast fishing and pollution, in just six hours.

“Based on the success of this first trial of LarvalBot [as this version of Dunbabin’s robot is called], we’re now really excited and plan to scale this up so we may have an army of underwater robots delivering billions of coral larvae over kilometre scales,” Harrison told me, explaining that the next test is the coral spawning event on the Great Barrier Reef this coming November. “Once we start getting to that scale of reef recovery we can really make a difference in terms of effectively changing the pathway of destruction to the recovery of coral reefs.”

However, for all the optimism surrounding the futuristic-sounding project, Harrison is aware that larval restoration is just one part of the solution to the coral crisis.

“What we’re trying to do at the moment is rescue the surviving corals that have survived major bleaching events and other destructive forces. But we can’t effectively continue to have coral reefs unless we manage climate change. Corals and the reefs they build are so sensitive to changes in environment such that we know that unless we control climate change in the next few decades, we’re going to lose more and more corals to the point where we won’t have functioning reefs on the planet.”