Coral bleaching

Updated: 24 March 2017

On 10 March 2017 the Great Barrier Reef Marine Park Authority confirmed mass coral bleaching is occurring on the Great Barrier Reef for the second consecutive year.

Mass coral bleaching is moderate to severe bleaching over a large spatial scale — the bleaching is part of an ongoing global event affecting the world’s coral reefs since 2014.

How this event unfolds on the Great Barrier Reef depends on local weather conditions over the next few weeks and, as updates become available, information will be released on this webpage and through our current conditions report.

Reported bleaching is consistent with the accumulated build-up of thermal stress across the Reef shown in the Bureau of Meteorology’s thermal stress mapping tools. Thermal stress has been accumulating Reef-wide, with accumulation greatest in the central region of the Reef between Townsville and Port Douglas.

Based on heat stress maps and reports to date, bleaching is likely to be more moderate south of Townsville with patches of severe bleaching. We've received reports of bleaching in the Keppels and as far south as Lady Elliot Island.

There are still many reefs throughout the Marine Park that have abundant living coral, and the Great Barrier Reef remains an iconic natural wonder.

As we saw last year bleaching and mortality can be highly variable across the 344,000 square kilometre Marine Park — an area bigger than Italy.

2017 bleaching timeline — to date
  • In January 2017 the Marine Park Authority began receiving increased reports of bleaching from marine park rangers, commercial operators and reef visitors submitting their observations through the Eye on the Reef monitoring program and from science partners.
  • On 21 and 22 February 2017 the Marine Park Authority conducted spot checks on reefs between Cairns and Townsville and this revealed moderate to severe coral bleaching at some reefs. A total of 54 in-water spot surveys of six reefs took place, with all six reefs surveyed showing signs of thermal stress.
  • Marine Park rangers from Queensland Parks and Wildlife Service and Marine Park Authority have been conducting further spot checks on reefs between Lizard Island and Townsville. Divers from the Association of Marine Park Tourism Operators have also been conducting reef health and impact surveys.
  • On 9 March 2017 experts from the Marine Park Authority spent six hours flying over the Reef between Townsville and Cairns, alongside researchers from the Australian Institute of Marine Science. The first aerial survey of the Reef for 2017 found severe bleaching in offshore reefs from north of Ingham to the northern extent of the survey near Cairns. This year more bleaching is being observed in this central part of the Reef, which last year escaped widespread severe bleaching.
  • On 16 March 2017 Marine Park Authority staff participated in the first of a series of comprehensive Reef-wide aerial surveys being conducted by the ARC Centre of Excellence for Coral Reef Studies. Preliminary information from the first survey indicated all reefs surveyed between Cairns and Lockhart River (the northern extent of the survey) showed bleaching to some extent, varying from mild to severe.
  • Severe bleaching has also been confirmed between Cairns and Ingham, with hotspots of severe bleaching inshore between Townsville and Mackay.
  • By the end of this week, the ARC Centre of Excellence for Coral Reef Studies would have completed aerial surveys of 1150 reefs across the Great Barrier Reef. GBRMPA is also conducting selective in-water surveys and working with the tourism industry to confirm the situation.
  • More detailed information will be available next week when information from the surveys can be entered in their computer database and analysed.
  • We will continue working with our partners to gather information on reef health to build a Reef-wide picture of how the Great Barrier Reef is faring this summer.

Along with the tourism industry we're urging Reef visitors and those working in the Marine Park to closely monitor coral condition and encourage reports through our Eye on the Reef app.

This bleaching highlights the importance of global action on climate change. It’s vital the world acts to implement the Paris Agreement to reduce greenhouse gas emissions.

It also highlights the critical importance of the work being done under the Reef 2050 Plan and the Authority’s ongoing management to build Reef resilience — such as zoning and controlling coral-eating crown-of-thorns starfish.

Anyone out on the water can help protect the Reef by following the zoning rules and responsible reef practices and leaving plant-eating fish to help control seaweed and enable coral larvae to settle and create new colonies.

Subscribe to our e-newsletter for further updates on Reef health and management.

Coral bleaching in 2016

In 2016 the Great Barrier Reef was affected by the worst coral bleaching on record.

Bleaching was highly variable throughout the 344,000 square kilometre area — many reefs throughout the Marine Park have abundant living coral, particularly in popular tourism locations in the central and southern regions, such as the Whitsundays and Cairns.

In September 2016 we released an interim report with results from surveys conducted between March and June 2016.

In November 2016 we released a supplementary report with preliminary findings from our surveys in October to November 2016.

Detailed findings will be available in early 2017.

An article in The Conversation provided further information on the assessment of the 2016 bleaching event and included a map summarising the results.

The article contained information from two rounds of Reef-wide reef health and impact surveys completed in 2016 by the GBRMPA and QPWS and further surveys by science partners.

The article’s simplified map showed impacts from the 2016 bleaching were highly variable along the 2300 km long Great Barrier Reef Marine Park. The “North” was worst affected by severe bleaching and subsequent loss of corals.

The “Far North (offshore)” includes outer-shelf reefs in the northernmost part of the Marine Park, and escaped the most severe bleaching and mortality, compared to elsewhere in the north.

The “Central” areas of the Marine Park had variable but low to medium loss of corals on average. The “South” had little or no loss of corals.

Coral bleaching news releases

News releases by the Great Barrier Reef Marine Park Authority on coral bleaching.

Read more on Coral bleaching news releases

Interim report: 2016 coral bleaching

Interim report by the Great Barrier Reef Marine Park Authority on the 2016 coral bleaching event.

Read more on Interim report: 2016 coral bleaching

Frequently asked questions

Find answers to your questions about bleaching on the Reef.

Read more on Frequently asked questions

Current conditions on the Reef

Summary and detailed information on sea surface temperature, tropical cyclones, rainfall levels and flood plumes to date.

Read more on Current conditions on the Reef

Record-breaking sea surface temperatures

Mass coral bleaching on the Great Barrier Reef in 2016 was triggered by record-breaking sea surface temperatures.

Read more on Record-breaking sea surface temperatures

Coral bleaching resources

Coral bleaching resources: Image gallery, bleaching infographic, informative video and map of observed bleaching.

Read more on Coral bleaching resources

Responsible reef practices – Spearfishing

Fishers and spearfishers should consider leaving plant-eating fish to help control seaweed and enable coral larvae to settle and create new colonies.

Read more on Responsible reef practices – Spearfishing

Student and teacher resources

Educational materials, including teaching units and a poster series, for primary and secondary school students.

Read more on Student and teacher resources

Eye on the Reef program

Eye on the Reef is a monitoring program that enables anyone who visits the Reef to contribute to its long-term protection.

Read more on Eye on the Reef program

Report your sightings

Download the free Eye on the Reef smart phone app from iTunes/Google play app store or you can use the desktop app to report your Reef sightings.

Read more on Report your sightings

Coral Bleaching Response Plan

The Coral Bleaching Response Plan was developed to meet the challenge of responding to coral bleaching events.

Read more on Coral Bleaching Response Plan

Sea surface temperatures

Australia’s Bureau of Meteorology provides information on sea surface temperatures for monitoring coral bleaching.

Read more on Sea surface temperatures


ReefTemp Next Generation is a set of high resolution mapping products that provide information on coral bleaching risk for the Great Barrier Reef region.

Read more on ReefTemp