Reef Health update | 11 December 2024

The Reef Authority continues to monitor conditions on the Reef and work with its science, Traditional Owner and management partners to prepare for the 2024–25 summer.

The summer has commenced with global sea surface temperatures remaining at near record highs, and forecast models predicting elevated ocean temperatures across the Great Barrier Reef Marine Park over the coming months.

This forecast indicates a risk of thermal stress building across the Reef during summer.

From December to March, there is a high chance of unusually high rainfall for parts of the Reef, particularly the Cape York peninsula, with above average predictions for all other Marine Park catchment areas.
Air temperatures are also expected to be warmer than average throughout January to March.

Overall, the Bureau of Meteorology forecasts a wet and warm December, and then drier and warm conditions over the Great Barrier Reef for January. An average number of cyclones is forecasted  typically four across the region. However, these cyclones are likely to be more intense due to warmer-than-average sea temperatures. 

November and early December conditions

Temperatures

Sea surface temperatures throughout the Northern and Central regions were about 0.5°C above average during November, and up to 0.8°C above average in the Southern Region. Currently, sea surface temperatures are 0.5°C above average for most of the Reef, but up to 1°C above average in the Far Northern and Southern regions.  

Rainfall

November saw lower than average rainfall for most Reef catchments. December is expected to bring higher than average rainfall particularly in the Northern regions.

Reef health

During November 559 Reef Health Impact Surveys  were conducted across 72 reefs in the Marine Park, recording a low incidence of coral bleaching and coral disease mainly from the Central Region, between Townsville and the Whitsundays. These comprehensive surveys, conducted by trained and experienced managers and researchers, are designed to enable rapid assessment of reef condition.

Crown-of-thorns starfish populations continue at outbreak densities at the Swains Reef in the Marine Park’s Southern Region, as well as on offshore reefs between Port Douglas and Lizard Island. Isolated outbreaks also persist on several reefs offshore Townsville and Whitsunday in the Central Region. 
The outbreak of this starfish between Port Douglas and Lizard Island, an area known as the ‘initiation zone’, is concerning for its potential to ‘seed’ secondary outbreaks on downstream reefs further south. 

In the lead up to the starfish’s breeding season, typically late December at the start of the tropical wet season, the control program’s focus is reducing its population in this initiation zone to suppress the buildup of the primary outbreak.

Reef management

Last week our annual summer workshop was held with management partners, Traditional Owners, scientists, tourism, and Reef-dependent industry representatives. Workshop participants focused on current conditions and the latest environmental forecast modelling to understand the likely outlook for summer, and to plan a coordinated approach for the months ahead.

It is too early to tell exactly what summer will bring, and local and regional conditions will ultimately influence Reef health outcomes.

Reef protection continues to be a year-round activity. We are working with our partners to protect and strengthen the resilience of the Reef through a range of management actions, including controlling coral-eating crown-of-thorns starfish and our year-round compliance campaign to deter illegal fishing.

If you are out in the Marine Park, you can report what you see through the Eye on the Reef app, and make sure you know your zones to help do your bit in protecting this World Heritage-listed natural wonder.
 

Reef Health update | November 2024

The Bureau of Meteorology is predicting a warm 2024–25 summer season as a result ongoing high sea surface temperatures. 

The Bureau, together with CSIRO, recently released the latest State of the Climate 2024 report, which looks at long-term climate trends in Australia. 

• The report found:
• Sea surface temperatures, ocean heat content, and acidification in the Marine Park have all been rising in recent decades.
• Since 1900, sea surface temperatures have increased by 1.08°C, contributing to more frequent extreme heat events, both on land and in the ocean.
• The world's oceans have absorbed over 90 per cent of the extra energy from greenhouse gases. 

The report highlights the importance of the work we do to build the resilience on the Great Barrier Reef, including programs such as the Crown-of-thorns starfish Control Program which is doing critical work to reduce outbreaks of the starfish to protect coral cover. 

On a positive note, it’s coral spawning season — a time of regeneration for the Reef, as spawning corals pass on heat-tolerant genes, helping the Reef adapt to warmer waters.

October conditions

During October, sea surface temperatures were about 0.5°C above average across the Marine Park.

Rainfall was slightly below average across Queensland, with low chances of extreme rain in November.

A total of 497 Reef Health Impact Surveys were conducted across 41 reefs in the Marine Park, showing minor coral bleaching in some areas, likely linked to earlier mass bleaching this year. Coral recovery and mortality remains varied across the Reef.

There were no reports of disease or physical damage (such as that caused by anchors) during these surveys. 

Crown-of-thorns starfish outbreaks continue to be an issue at some reefs, particularly in areas like Swain Reefs and offshore Port Douglas, and isolated outbreaks are ongoing on several reefs offshore Townsville and the Whitsundays.

During coral spawning, the focus of the Crown-of-thorns starfish control program is to reduce starfish populations to protect the Reef's recovery.

Reef management

With summer approaching, the Reef is more vulnerable to extreme weather like cyclones and heatwaves. 

We’re working closely with partners including the Queensland Parks and Wildlife Service through the Reef Joint Field Management Program, as well as the tourism industry and scientific organisations such as the Australian Institute of Marine Science to monitor the Reef 24/7.

Over the past month, we've been working with the tourism industry, running Eye on the Reef training which teaches operators how to gather important data on Reef health, which we use year-round to monitor conditions.

The training will continue this month, including training a new cohort of Master Reef Guides. 

Our year-round management actions are geared towards building and supporting Reef resilience, including enforcing compliance with the Reef’s zoning plan and ensuring people are enjoying the Reef in a responsible way.

Stay up-to-date with what’s happening across the Reef by following our social channels and downloading the Eye of the reef app to let us know what you see in the Marine Park.

Reef Health update | October 2024

Global sea-surface temperatures remain above average across most of the planet.

Sea-surface temperatures across the Great Barrier Reef Marine Park are around 0.6°C higher than average for this time of year but these temperatures are not at levels that typically cause impacts such as coral bleaching.

Sea-surface temperatures across the Marine Park are expected to remain from 0.4 to 1.2°C above average from October to December. However, local weather conditions will have a key influence on sea surface temperatures during the summer.

The El Niño–Southern Oscillation weather pattern’s neutral condition remains, and the Bureau of Metrology predicts these neutral conditions to continue over the summer.

Reef Health summary for September  

This Reef Health update is based on data collected during September, 2024.

In September, 348 Reef Health Impact Surveys (RHIS) were conducted across 31 reefs in the Marine Park.

Reef Health Impact Surveys are a quantifiable survey method used mostly by the Reef Authority, Queensland Parks and Wildlife Service and researchers as well as trained tourism operators.

Most reefs surveyed showed no signs of coral bleaching, with very few cases of minor bleaching reported in each region. Any coral bleaching observed is not likely related to current sea-surface temperatures as they are under the levels that would usually cause coral bleaching. The surveys also found minor damage (for example, from anchor damage) on some corals but no signs of disease in all regions of the Marine Park.

There was average or below average rainfall reported across all Reef catchments in September.

The highest known crown-of-thorns starfish outbreak densities continue at some reefs in the offshore Southern Region (Swain Reefs) and isolated outbreaks remain on several reefs offshore Townsville and Whitsunday in the Central Region.

The Crown-of-thorns starfish Control Program is in operation, helping us to target those veracious coral predators so we can support the recovery of coral ecosystems and their resilience into the future.

Reef management

The Reef Authority collaborates with science and management institutions to maintain a contemporary understanding of Reef health and the impacts of climate change on the World Heritage Area.

The Australian Institute of Marine Science, the Bureau of Meteorology, CSIRO, and other research institutions continue to deliver monitoring and research that documents the long-term trend of Reef conditions and climate patterns. This includes multiple monitoring programs under the Reef 2050 Integrated Monitoring and Reporting Program.

During the summer months, the Reef is more vulnerable to extreme weather events including cyclones, marine heatwaves and flooding – the effects of which are compounded by climate change.

As we move into the warmer months, there is a lot of work being done with our partners to prepare for summer.

We are also preparing for the upcoming coral spawning, which only occurs a few nights of the year. During this phenomenal event, millions of bundles of coral sperm and eggs are released into the ocean allowing for mass reproduction—a positive sign for Reef renewal and regeneration.

You can do your bit to help protect the Reef by following a few simple steps:

• Use public moorings where available and do not anchor within no-anchoring areas – they are there to protect the coral.
• Where possible, anchor in sand or mud away from corals and other fragile marine environments. Suitable areas often show up as flat and smooth on your sounder.
• Never wrap anchor rope or chain around bommies or large coral heads.
• If anchoring overnight, anchor before nightfall and double-check the swing room.
• Use your sand anchor and reef pick appropriately to minimise damage.
• Motor towards the anchor when hauling it in and retrieve the anchor when the line is vertical.
• If the anchor is caught on a reef, free it by hand wherever possible.
• Do not force the anchor free by motoring forward.
• Keep watch to make sure the anchor isn’t dragging.