New study aims to assist recovery of coral reefs

A new project by a Southern Cross University researcher to re-seed damaged coral reefs in the Maldives has important implications for the recovery of coral reefs around the world.

One of Australia’s leading coral experts, Associate Professor Peter Harrison, who is the director of the University’s Coral Reef Research Centre in the School of Environmental Science and Management, said the coral reefs in the Maldives provided an excellent opportunity to develop effective coral larval re-seeding methods.

“We have already lost 20 per cent of the world’s coral reefs and another 50 per cent are under significant threat. There is an urgent need for research on larval re-seeding techniques as they have great potential to assist the recovery of damaged reef systems around the world,” Professor Harrison said.

The Maldives are located in the Indian Ocean, south of India, and consist of 22 atolls and about 1,200 small coral islands. The population’s main source of income is from tourism and fisheries, hence the health of local reefs is vital to their economy and existence.

Professor Harrison, who has recently returned from an invited research expedition to the islands, said there had been very little detailed research done on the coral reefs in that part of the world.

“In 1998 the Maldives lost up to 90 per cent of their corals due to a massive coral bleaching event, which also affected corals on the Great Barrier Reef and around the world. The Maldives were among the worst impacted coral reefs, so I went over there with a lot of concern about what I would find,” Professor Harrison said.

“But, although some of the coral communities haven’t recovered, the islands I was working on had reefs that were starting to recover and that has happened naturally since the 1998 bleaching event.”

Professor Harrison said his initial research in the area involved monitoring and recording the coral spawning, as there have been no detailed studies of coral spawning in the Maldives.

“It was a really fascinating pattern that I haven’t seen anywhere in the world. Instead of spawning together, as happens on the Great Barrier Reef, the different coral colonies were spawning mostly on different nights over a six-week period, with a small peak in spawning when about 20 per cent of the corals spawned together,” he said.

“The successful local coral spawning may partly explain the rapid regrowth of the coral on some of these reefs and provides some hope for the ability of at least a few reefs to recover.”

However, he cautioned there was still a very real threat from global climate change causing increased coral bleaching and increased sea level.

“Some reefs may be able to recover between these major bleaching events, but if sea temperatures continue to rise as they are predicted to, most coral colonies and reef communities will be simply overwhelmed during the next 50 years,” he said.

Professor Harrison said he was now planning a major project to collect the coral spawn, grow the coral larvae and use them to re-seed parts of the reef that had not recovered.

He said once a reef was severely damaged from an event such as mass coral bleaching there was an increased risk of reef erosion and ecosystem collapse.

“The Maldives provide a perfect opportunity to determine how coral re-seeding can be developed on a larger scale,” he said.

“I’m confident this process could be applied to other reef systems around the world and provide a new way to repair these critically important marine environments.”

Photo: Some reefs in the Maldives are starting to recover from a massive coral bleaching event in 1998, which led to the loss of up to 90 per cent of the corals. A new project by Southern Cross University will assist that recovery.