Reef health

Fact or fiction: coral bleaching 101

Do you know what is fact or fiction?

As Australia’s lead management agency for the Reef, we monitor Reef conditions very closely throughout the year. From May to November each year, we issue regular Reef health reports. Over summer, we issue weekly public reports on the conditions of the Reef.

These updates are based on forecasts, water temperature heat mapping, in-water surveys, citizen science and aerial surveys. The current updates are available below and past Reef health updates are also available.

In addition to our regular updates, we’ve released:


Reef health update - 29 April 2021

This week saw the release of the second annual Reef Snapshotproduced by the Great Barrier Reef Marine Park Authority, Australian Institute of Marine Science (AIMS), and CSIRO.

The snapshot provides a concise, easy-to-understand summary of how the Reef has fared over the past summer, what this means for coral, and the actions being taken to help coral health.

Among the findings from the 2020-21 summer:

  • There were no prolonged high temperature or major cyclone disturbances, and many reefs continued their recovery from past impacts.
  • Water temperatures did not cause as much coral heat stress as recent years, although all months were warmer than average.
  • Cyclone Kimi was the only tropical cyclone that tracked across the Reef, and its potential to cause widespread catastrophic damage to reefs was assessed as very low.
  • While there was some good rainfall in the catchment, flood levels in waterways near the Reef were generally not major or sustained.
  • Crown-of-thorns starfish remain at outbreak or potential outbreak levels in parts of the northern, central and (particularly) southern regions of the Reef. The Crown-of-thorns Starfish Control Program continues to work in all three regions to cull starfish down to non-outbreak levels.

From here, we will release monthly updates on Reef health until the beginning of the summer 2021-22.