The recovery in the central and northern regions of the UNESCO World Heritage Site contrasts with the southern region, where there has been a loss of coral cover due to thorn star outbreaks, the Australian Institute of Marine Sciences (AIMS) said. in its annual report. “What we’re seeing is that the Great Barrier Reef is still a resilient system. It still retains that ability to bounce back from perturbations,” AIMS monitoring program chief Mike Emsley told Reuters. Sign up now for FREE unlimited access to Reuters.com Register “But the concern is that the frequency of these disturbance events is increasing, particularly massive coral bleaching events,” he said. The report comes as UNESCO considers whether to list the Great Barrier Reef as “at risk”, following a visit by UNESCO experts in March. The World Heritage Committee meeting where the reef’s fate was on the agenda was due to be held in Russia in June, but was postponed. Mixed reef fish swim over a coral drop colony as it grows on the Great Barrier Reef off the coast of Cairns, Australia, October 25, 2019. REUTERS/Lucas Jackson read more In a key measure of reef health, AIMS defines hard coral cover of more than 30% as high value, based on its long-term surveys 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 ever have been recorded for both areas 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, cover 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. Although extensive, the institute said, the bleaching in 2020 and 2022 was not as damaging as in 2016 and 2017. On the other hand, the growth in coverage is due to Acropora corals, which AIMS said are particularly vulnerable to wave damage, heat stress and thorn starfish. “We’re really in uncharted waters in terms of the effects of bleaching and what it means moving forward. But as of today, it’s still a fantastic place,” Emslie said. Sign up now for FREE unlimited access to Reuters.com Register Reporting by Sonali Paul in Melbourne and James Redmayne in Sydney. Edited by Stephen Coates Our Standards: The Thomson Reuters Trust Principles.