Reef health

Fact or fiction: coral bleaching 101

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Reef health

As Australia’s lead management agency for the Reef, we monitor Reef conditions very closely.

Over summer 2019-20 we issued weekly public reports about conditions on the Reef – the full series of information and video updates are below.

With summer over, we are now releasing monthly updates until the beginning of summer 2020-21 when we’ll resume weekly updates.

These updates are based on forecasts, water temperature heat mapping, in-water surveys, citizen science and aerial surveys.

We also released statements about the mass coral bleaching that occurred on the Reef and a statement on aerial surveys, along with educational information on coral bleaching.

The Authority acknowledges the extreme impact that COVID-19 is having on tourism businesses and their communities and we are doing everything we can to support the industry in these difficult times.

When it is safe to do so, we will encourage people from across Australia and around the world to see the Reef, love the Reef, and importantly protect the Reef.

Reef snapshot 2019-20

Reef health snapshot

Reef health snapshot 2019/20

In addition to our regular updates, we’ve released the first Reef snapshot: summer 2019-20.

The snapshot is a joint initiative of the Great Barrier Reef Marine Park Authority, the Australian Institute of Marine Science and CSIRO.

You can access more information, download the full snapshot, and watch the explainer video on our website.

Reef health updates

With summer 2019-20 over, we are now releasing monthly updates until the beginning of summer 2020-21 when we’ll resume weekly updates.

Report covering April 2020

We acknowledge the significant impact COVID-19 is having on Reef related-industries and communities and welcome additional support announced by the Australian Government for tourism and regional economies.

We are continuing to provide updates on Reef health during this time – updates will be monthly until the start of the 2020-21 summer.

2019-20 wet season wrap-up

Northern Australia’s 2019-20 wet season was the driest since 2004-05, and the second well-below average wet season in a row, according to the Bureau of Meteorology. Tropical cyclone numbers were also well below the long-term average.

Temperature and rainfall outlook

Sea surface temperatures throughout the Marine Park were generally average at the end of April.

The Bureau of Meteorology is forecasting warmer and wetter than average conditions for Queensland through to August.

Reef snapshot: summer 2019-2020

In April 2020, we released the first Reef snapshot with the Australian Institute of Marine Science and CSIRO. It is 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. The snapshot found:

Northern (Cape York – Lizard Island): Moderate hard coral cover and low levels of crown-of-thorns starfish (COTS). Bleaching moderate to severe on mid-shelf and inshore reefs, with little to no bleaching on outer-shelf reefs.

Central (Lizard Island – Whitsundays): Moderate hard coral cover in Cairns and low in Innisfail overall, with no COTS observed. Moderate bleaching levels near Cairns, but generally more widespread and severe bleaching on mid-shelf reefs further south (except the Whitsundays).

Southern (Whitsundays – Cap-Bunkers/Swains):  Hard coral cover and active COTS in the Pompeys, high levels of hard coral cover in the Cap-Bunkers and moderate levels of hard coral cover and COTS outbreaks in the Swains. Variable bleaching observed overall, with two-thirds of reefs moderately to severely bleached in the Pompeys and Swains.

Coral bleaching recovery

Surveys of post-bleaching recovery and mortality have not been conducted due to COVID-19 social distancing and travel restrictions. As a result, we are mostly reliant on reports from locals and tourism operators.

Magnetic Island is showing signs of recovery from the recent mass bleaching event in the 2019-20 summer. Reports show corals and giant clams are regaining some of their function/colour.

Footage from four reefs offshore from Cairns show healthy coral with small amounts of bleaching.

Early reports from the Marine Monitoring Program show encouraging signs of recovery on inshore sites in the Burdekin and Keppels Islands.

Observations of coral disease submitted through the Eye on the Reef program indicated scattered, low-level impacts.

Crown-of-thorns starfish management

The crown-of-thorns starfish control vessels commenced culling at four reefs in the Capricorn-Bunker Group which are currently in active outbreak status.

Rare sighting reported on Eye on the Reef

Footage of a rare and endangered ornate eagle ray was sighted near Lady Elliot Island. There are only about 50 sightings recorded for this species world-wide.