Larval Reseeding

Researchers have successfully piloted small-scale coral restoration on the Reef, with a technique called larval reseeding - capturing coral eggs and sperm during spawning to rear coral larvae before delivering these healthy 'baby' corals onto small areas of reefs. 

During the November 2016 coral spawning, Professor Harrison and his team travelled to the Great Barrier Reef’s Heron Island for the Australian-first trial. They collected vast quantities of coral eggs and sperm during mass spawning, using them to grow more than a million coral larvae, and then delivered the larvae onto reef patches in underwater mesh tents.

Eight months later Professor Harrison’s team returned to Heron Island to discover more than 100 surviving juvenile corals established on the settlement tiles out on the Reef. The research was not without its challenges including the need for careful rearing of coral larval cultures and complex diving operations on the reef by the research team.

Professor Harrison’s Great Barrier Reef research builds on the success of his team’s work in the Philippines in an area of reef highly degraded by blast fishing which had similar positive results.

“Our previous studies in the Philippines funded by the Australian Centre for International Agricultural Research, showed that corals can grow from microscopic larvae to dinner plate sized adult colonies within three years and they were able to sexually reproduce. This work at Heron Island is the first step towards proving we can apply these techniques on the Great Barrier Reef,” Professor Harrison said.

He sees great promise in the mass larval restoration approach and says it has the potential to make a difference to reef recovery on a larger scale using natural coral spawn slicks that contain many millions of larvae from different coral species.

“This is the first project of its kind on the Great Barrier Reef to successfully re-establish a population of juvenile corals from larvae settling directly on the reef,” said Southern Cross University’s Professor Peter Harrison, lead researcher on the project.

“This pilot study carried out on Heron Island shows that our new techniques to give corals a helping hand to conceive and then settle, develop and grow in their natural environment can work on the Great Barrier Reef.

“The success of this new research not only applies to the Great Barrier Reef but has potential global significance – it shows we can start to restore and repair damaged coral populations where the natural supply of coral larvae has been compromised.”