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The Great Barrier Reef

The Great Barrier Reef is renowned internationally for its ecological importance and beauty. It is the largest and best known coral reef ecosystem in the world, extending over 2,300 kilometres along the Queensland coast and covering an area of 350,000 square kilometres. It includes over 2,900 reefs as well as extensive seagrass meadows, mangrove forests and soft bottom habitats.

The high biodiversity of the region is important for the continued survival of many species. The reef is also critical for the prosperity of Australia, annually contributing over $6 billion to the Australian economy.

It is home to thousands of species, including coral and other invertebrates, bony fish, sharks, rays, marine mammals, marine turtles, sea snakes and seabirds, as well as a wide variety of other animals, algae and other marine plants. The reef also provides an important habitat for species of conservation concern such as dugongs, whales, dolphins, marine turtles and some species of shark.


The Great Barrier Reef is one of the most healthy and well managed coral reef ecosystems in the world. However, the Great Barrier Reef Outlook Report shows that the future health and resilience of the reef remains under threat from a range of factors including climate change, poor water quality, coastal development and the remaining impacts from fishing.

Over the past 150 years extensive modification for urban and transport infrastructure, agricultural production, tourism and mining has resulted in a dramatic decline in the quality of water flowing into the reef lagoon – the largest contribution being from agricultural land use activities in the catchment areas. Monitoring has shown that pesticides and pollutants are being transported into river systems and the Great Barrier Reef at harmful concentrations during flood events.

The Great Barrier Reef receives runoff from 35 major catchments, which drain 424,000 square kilometres of coastal Queensland.

Unfortunately, the combination of increased development and changing land use has resulted in a significant decline in the quality of water flowing into the reef lagoon. Floods in the wet season carry low salinity waters and loads of nutrients, sediments and pesticides from the adjacent catchments into the reef lagoon. These levels are well above natural levels and many times higher than in non-flood waters.

The inshore area (within 20 kilometres of the shore), which makes up approximately eight per cent of the Great Barrier Reef Marine Park, is at most risk.   The inshore area supports significant ecological communities and is also the area most used by recreational visitors, commercial tourism operations and commercial fisheries.

In response to these issues, the Queensland and Australian governments established the Reef Water Quality Protection Plan in 2003. This plan was updated in 2009 and 2013. It was reviewed in 2017 and renamed the Reef 2050 Water Quality Improvement Plan. For the first time, the plan addresses all land-based sources of water pollution including agriculture, urban, industrial and public lands. Improving the quality of water entering the reef will build the resilience of the reef to adapt to and recover from other impacts such as climate change.

Last updated
19 July 2018

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