The process made use of the annual coral spawning event, which sees a “kaleidoscope” of fragile sperm and coral eggs floating on the surface of the water.
The scientists captured samples of this patch and transported it to floating “larval breeding pools” anchored in sandy areas of the reef.
The team then monitored fertilization rates and cultured the larvae for five to seven days. This week, once they were fully developed, the scientists released the larvae into target areas that needed live coral.
It is the fifth time the technique has been used on a damaged section of Queensland’s natural wonder. The process began in 2016 on Heron Island.
Professor Harrison told 9news.com.au that the latest project made use of three local tour operators and is already showing signs of success.
“Just a few days ago we dumped some of the larvae back into the damaged reef areas on Hook Island and we were able to get some of them to settle.”
Professor Harrison believes that in three to five years, entire kilometers of damaged reefs could be replanted.
“Every time we attend these coral spawning events, we learn more about how to make the process more efficient,” he said.
“In the next few years we hope to grow hundreds of millions of larvae.
“Hopefully within a few years we will have dozens of groups with their own boats capturing coral spawning, cultivating larvae and returning it to damaged areas.”
Professor Harrison has spent over 30 years studying the complexities of coral reproduction and has been dreaming of Coral IVF “for decades”.
One of the most encouraging aspects of his research, he said, was the fact that the process increases the possibility that larvae with strong genes will leak through the population creating what he called “enhanced coral.”
“Even if you get high fertilization rates naturally, most of the larvae produced end up moving away from the main reef,” he said.
“What we are trying to do now is to rescue the surviving coral populations. We know that in many areas of the reef more than half of the corals have been removed by bleaching events and crown-of-thorns and cylons and so on.
“By taking the seed from surviving corals, we know that the next generation is more likely to survive, because they come from parents who have survived damaging events.”
Development couldn’t come fast enough, as the Great Barrier Reef suffered its third mass bleaching event last summer.
While it’s too early to tell if this year will see another such event, Great Barrier Reef Foundation Managing Director Anna Marsden says the signs are pointing towards one.
“Once around February comes around, we’ll start keeping an eye on it,” Marsden told 9news.com.au.
“There are expectations and concerns that we will have a hot summer, and the conditions that normally mean bleaching, heat, low clouds and little wind are there. This means the water is getting hotter and hotter and the coral is cooking.”
The Bureau of Meteorology forecast also indicated a hot summer ahead.
Despite the extreme weather warning, Professor Harrison has “genuine hope” that Coral IVF can help protect the diseased reefs of Queensland and the world.
“Now that we have tested this technique on the Great Barrier Reef, we are confident that it can be applied to most other reef areas in the world,” he said.
“If we hit kilometer scales in the next three to five years, then we have a genuine hope of repairing coral communities quickly enough to counter the threats of rising sea temperatures, crown of thorns outbreaks and supercyclones “.