Parts of Australia’s Great Barrier Reef have highest coral cover in 36 years

MELBOURNE/SYDNEY, Aug 4 (Reuters) – Two-thirds of Australia’s Great Barrier Reef has shown the most amount of coral cover in 36 years, but the reef remains vulnerable to increasingly frequent massive bleaching, reported a formal long-term monitoring program on Thursday. .

The recovery in the central and northern parts of the UNESCO-listed reef contrasts with the southern region, where there has been loss of coral cover due to outbreaks of crown-of-thorns starfish, said the Australian Institute of Marine Science (AIMS). in its annual report.

“What we’re finding is that the Great Barrier Reef is still a resilient system. It still retains that ability to recover from disturbances,” AIMS monitoring program manager Mike Emslie told Reuters.

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“But what is worrying is that the frequency of these disturbance events is increasing, especially massive coral bleaching events,” he said.

The report comes as UNESCO considers classifying the Great Barrier Reef as “endangered”, following a visit by UNESCO experts in March. The World Heritage Committee meeting where the fate of the reef was on the agenda was due to be held in Russia in June but was postponed.

In a key measure of reef health, AIMS defines hard coral cover of more than 30% as high, based on its long-term studies of the reef.

In the northern region, average hard coral cover increased to 36% in 2022 from a low of 13% in 2017, while in the central region hard coral cover increased to 33% from a low of 12% in 2019 – the highest levels recorded for both regions since the institute began monitoring the reef in 1985.

In the southern region, however, which generally has higher hard coral cover than the other two regions, coverage fell to 34% in 2022 from 38% a year earlier.

The recovery comes after the fourth mass bleaching in seven years and the first during a La Nina event, which usually brings cooler temperatures. While significant, according to the institute, bleaching in 2020 and 2022 was not as damaging as in 2016 and 2017.

In contrast, cover growth was driven by Acropora corals, which AIMS says are particularly vulnerable to wave damage, heat stress and crown-of-thorns starfish.

“We’re really in uncharted waters when it comes to the effects of bleaching and what that means moving forward. But to this day, it’s still a fantastic place,” Emslie said.

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Reporting by Sonali Paul in Melbourne and James Redmayne in Sydney; Editing by Stephen Coates

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