Millions of coral larvae on the Great Barrier Reef now have a significantly higher chance of replenishing degraded reefs, thanks to an innovative coral restoration technology developed by CSIRO, Australia’s national science agency, in collaboration with Southern Cross University. This breakthrough, known as the ‘larval seedbox,’ has shown remarkable promise in its first trial, conducted at Lizard Island in 2024.
The trial results are nothing short of impressive. Coral settlement was found to be up to 56 times higher across thousands of square meters of reef, marking a substantial leap forward in coral restoration efforts. Dr. Christopher Doropoulos, Senior Research Scientist at CSIRO, explained the mechanism behind this success: “The larval seedbox is a simple, efficient, and cost-effective tool designed to enhance coral larval survival, delay their dispersal, and help them find optimal habitat for settlement.”
The process begins with the annual mass coral spawning event, where various coral species release bundles of eggs and sperm into the water. Researchers collect these bundles, culture the coral larvae, and then fill the larval seedboxes with tens of millions of these larvae. These seedboxes are then deployed onto the reef, where the larvae exit when ready and drift with the currents, covering areas of more than two hectares. This method allows for a high density of larvae to be distributed over much larger areas than previously possible, significantly boosting the potential for coral restoration at scale.
Dr. Doropoulos further elaborated on the functionality of the seedboxes: “The seedboxes act as a delivery system, giving coral larvae more time to disperse and settle on the Great Barrier Reef. This enables them to establish themselves and grow into juvenile corals.”
As the annual mass coral spawning event approaches in November, a second trial is currently underway in the Whitsundays. Professor Peter Harrison from Southern Cross University highlighted the importance of this ongoing research: “This trial will provide a valuable opportunity to test the effectiveness of the technique in a variety of reef conditions. We’re anticipating the release of up to 20 million larvae at multiple locations, and the team will continue to monitor the longer-term effectiveness of the larval seedbox delivery over nine to 12 months.”
This collaborative research effort involves CSIRO and Southern Cross University, with support from the Great Barrier Reef Foundation, the Australian Institute of Marine Science, and local stakeholders. The findings from the first trial at Lizard Island will soon be published in the journal Ecological Applications, providing further insights into the potential of this innovative technology.
The success of the larval seedbox technology represents a significant milestone in the quest to restore and protect the Great Barrier Reef. By leveraging cutting-edge science and collaborative efforts, researchers are paving the way for scalable and effective coral restoration, offering hope for the future of this vital marine ecosystem.