SYDNEY (AFP) – Scientists have launched the largest ever attempt to regenerate coral on the endangered Great Barrier Reef by harvesting millions of creatures' eggs and sperm during their annual spawning.
The researchers said on Wednesday (Nov 28) they plan to grow coral larvae from the harvested eggs and return them to areas of the reef that were badly damaged by climate-related coral bleaching.
"This is the first time that the whole process of large scale larval raising and settlement will be conducted directly on reefs at the Great Barrier Reef," said Professor Peter Harrison of Southern Cross University, one of the project leaders.
"Our team will restore hundreds of square meters with the goal of getting to square miles in the future, a scale not attempted before," he said in a statement.
The "Larval Restoration Project" launch was timed to coincide with the annual coral spawn on the reef, which began earlier this week and will last only about 48 to 72 hours.
Coral along large swathes of the 2,300km reef have been killed by rising sea temperatures linked to climate change, leaving behind skeletal remains in a process known as coral bleaching.
The northern reaches of the reef suffered from an unprecedented two successive years of severe bleaching in 2016 and 2017, raising fear that may have suffered irreparable damage.
Professor Harrison and his colleagues are hoping their reseeding project can help to reverse the trend, but he warned that the effort would not be enough on his own to save the reef.
"Climate action is the only way to ensure coral reefs can survive into the future," he said.
"Our approach to reef restoration aims to buy time for coral populations to survive and evolve until emissions are capped and our climate stabilizes."
The scientists hope that coral that has survived bleaching has a greater tolerance to rising temperatures so that a breeding population produced from this year's spawn will grow into coral better able to survive future bleaching events.
The researchers, who include experts from James Cook University and the University of Technology Sydney (UTS), said a novelty of their reseeding project was to grow coral larvae together with microscopic algae. The two live in symbiosis on the reef.
"So we are aiming to keep track of this process to see if the survival and early growth of juvenile corals can be boosted by rapid uptake of algae," said Associate Professor David Suggett of UTS.