The Great Barrier Reef has recorded its highest levels of coral cover in the 40-year history of Australia’s long-term monitoring program, with all five record years occurring since 2021.

The findings come from the Australian Institute of Marine Science’s long-running reef monitoring program, which tracks changes in coral communities across the Great Barrier Reef.

Coral cover is an important measure of reef health because it reflects the amount of living hard coral covering the reef. The recent measurements show that, despite significant disturbances affecting parts of the reef, coral cover across monitored areas has reached historically high levels.

The five highest years in the monitoring record have all occurred within the past several years, beginning in 2021. The trend has been driven in part by periods of strong coral growth and recovery in areas where conditions have allowed coral colonies to expand.

The figures provide a broader picture of the reef than individual bleaching events or damage at particular locations. Coral cover can rise substantially during periods of favorable conditions, while cyclones, coral-eating crown-of-thorns starfish and marine heatwaves can cause sharp declines.

The long-term data therefore highlights both the reef's capacity for recovery and the continuing fluctuations affecting coral ecosystems.

The Great Barrier Reef remains one of the world's largest and most closely monitored coral reef systems, stretching for more than 1,400 miles along Australia's northeastern coast. The latest monitoring results offer evidence of substantial coral growth in recent years, even as scientists continue tracking other pressures on the reef.