A technique known around the world for its success in restoring damaged coral reefs, coral larval restoration is an idea conceived by Southern Cross University’s Distinguished Professor Peter Harrison during the discovery of the mass coral spawning on Australia’s Great Barrier Reef (GBR) in the early 1980s. Unlike laboratory-based reseeding efforts, Coral IVF or larval reseeding, is conducted directly on coral reefs.
Based on natural sexual reproduction processes, a small fraction of the trillions of eggs that corals release during their mass spawning season, are collected and placed in floating ocean pools to grow into larvae. Around a week later when the larvae are ready to settle and become baby corals, the Coral IVF team releases them directly onto degraded areas of reef.
Professor Harrison gradually developed techniques to enable the research discoveries to be applied to restoration of degraded coral reefs. The first reef trial was successfully completed in 2013 with then-Ph.D. candidate Dexter dela Cruz in the Philippines. This was the first study to show that increased larval supply and settlement directly onto highly degraded and algal phase-shifted reefs could successfully restore breeding coral populations within three years. Since then, many successful reef trials have been done on damaged reefs in the Philippines, and now a Technical Report has been published to explain how and why the coral spawn collection, larval culturing and dispersal methods and equipment have evolved over time, and to acknowledge the many funding organizations and people who have helped along the way.
“This reef-based approach avoids problems and increased costs associated with collecting breeding corals, coral spawning and larval production in the laboratory, and allows us to grow many millions of coral larvae in natural reef environments that can be simply released into damaged reef environments using a variety of innovative techniques,” Professor Harrison said. He added, “increasing attention has been focused on scaling up larval production directly on reefs and we’re now routinely producing many tens-of-millions of larvae after spawning events, and establishing new projects in the Maldives, Caribbean and Southeast Asian reef regions.
Professor Harrison is following up the Technical Report with a practical training guide for coral larval restoration methods that can be used by organizations and local communities around the world.
More information: Peter L Harrison et al, Methods for restoring damaged reefs using coral larval restoration, Southern Cross University (2022). DOI: 10.25918/report.233
