NUSA DUA: Using a snorkel and protective gloves, Pariama Hutasoit dives down into the clear waters off the Indonesian island of Bali to pull away plastic from a "reef star" installed by her conservation group to encourage new coral growth.

The Nusa Dua Foundation has installed almost 6,000 of the stars, hexagonal-shaped steel structures around a metre in diameter, in coral reefs across Bali. The stars bridge gaps in the reefs where coral has died, supporting regrowth.

"We're aiming to install about 5,000 reef stars over the next five years," Hutasoit, 52, a former World Wildlife Fund employee, told Reuters. "And in the future, we also if possible want to expand outside Bali for the restoration of coral reefs."

The Indonesian archipelago harbours more than 75% of the world's coral species, many of which are facing erosion and bleaching every year, according to the Coral Triangle Initiative, a transnational coral restoration project.

Only just over half of Bali's coral reefs are considered to be in "good" condition with 30% in "poor" condition and the remaining 15% in "very poor" condition, according to a 2018 report by Bali's Marine and Fisheries Department.

The damage has been attributed to human activity, including destructive fishing, global warming, and heavy waves.

Part of the Nusa Dua Foundation's remit is holding community outreach programs, attempting to educate local residents about the importance of protecting Bali's coral reefs.

I Nyoman Sadnya, a local fisherman, said his parents had mined coral from the island's reefs for decades, unaware of the destructive long-term impact.

"My parents did not have a job and the area here used to be an arid area, and sometimes it was difficult to find food," he said. "So my parents resorted to coral mining for building materials, because they didn't know (it was bad)."

Coral, popularly used for house foundations and decorative pieces, was a source of income for his parents.

"By looking at the condition of coral reefs today, we realise that what we did in the past to them was totally wrong," he said.

Hutasoit is using World Oceans Day on June 8 to plea for more support for coral reef regeneration.