Current conditions on the Reef
Each summer, we assess the health of reefs, as this part of the year poses a greater risk of coral bleaching, extreme weather and flooding.
Stressful conditions can lead to coral disease outbreaks, while poor water quality can also lead to greater numbers of coral eating crown-of-thorns starfish.
2012/2013 summer wrap up
Conditions on the Great Barrier Reef remain neutral according to the Bureau of Meteorology:
- The El Niño-Southern Oscillation is within the neutral range, indicating there is neither a drought- or wet-dominated cycle generally assoicated with El Niño or La Niña cycle conditions. This is set to continue through autumn and into early winter.
- Sea surface temperatures in the tropical Pacific Ocean have been persistently warm since December 2012.
- Ex-tropical cyclone Oswald crossed Cape York Peninsula on 21 January 2013 and moved down the Queensland coast, bringing strong to gale force winds, heavy rain, damaging waves and floods.
- In May 2013, ex-tropical cyclone Zane crossed into the Marine Park from the Coral Sea and moved over Cape York Penisula, affecting areas from Cape Grenville to Cooktown.
- Queensland received below average rainfall levels during summer, apart from the south-east of the state and parts of the Central Coast. In these areas, rainfall in January 2013 was 50–400mm higher than the monthly average due to the influence of ex-Tropical Cyclone Oswald.
- Heavy rain from ex-tropical cyclone Oswald produced flooding in many of the major river systems that flow into the Great Barrier Reef or bays in southern Queensland. Minor to major flooding occurred in all major river systems south of Mackay to the Queensland–New South Wales border. Flood plumes were documented in several of these river systems.
Coral reef health reports
Together with the Queensland Parks and Wildlife Service (QPWS) and the Eye on the Reef monitoring network, we have carried out 693 reef health and impact surveys across 78 reefs on the Great Barrier Reef since 1 December 2012. Most (73 per cent) of these surveys were completed offshore from Cairns and Cooktown.
Of all the surveys, 31 per cent recorded healthy coral reefs with no impacts, 34 per cent had one type of impact, and another 35 per cent recorded more than one impact. Crown-of-thorns starfish were seen in 37 per cent of surveys, while Drupella snails — which can cause extensive coral reef damage if they’re high in number — were recorded in only 4 per cent of surveys. Some signs of coral stress, such as low level coral bleaching and disease, were also evident on 20 to 30 per cent of surveyed reefs.
Signs of coral damage could be seen in approximately 27 per cent of surveys. This damage was generally minor, such as on tips and edges of corals. Moderately severe damage, such as broken branches, was seen in about 12 per cent of cases. Anecdotal reports from tourism operators, researchers and volunteers indicate some of this damage was caused by ex-Tropical Cyclone Oswald.
In the wake of this weather event, there were reports of moderate to major levels of damage on reefs from Cairns to the Capricorn Bunker Group. High winds and heavy rainfall may have affected individual coral reefs and seagrass beds, particularly in southern areas. Effects include physical damage from waves, as well as the effects of low salinity, sediments and turbidity from flood plumes.
A Vulnerability Assessment: of the issues that could have far-reaching consequences for the Great Barrier Reef.
Current Conditions: Environmental and climatic forecasts for the Great Barrier Reef