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Great Barrier Reef

Pressure on the Great Barrier Reef

The Great Barrier Reef we see today is about 12,000 years old, and for most of that time there has been minimal human presence. Around 1850, European settlers began populating and developing the Queensland coastal strip, along the inner boundary of the Great Barrier Reef.

During that time, human settlement has impacted the Great Barrier Reef. Nowadays, the water isn't as clean, the coral isn't as healthy, there are fewer fish and some animals and birds aren't as common as they once were.

Tropical fish

A lot has changed on the Great Barrier Reef over the last 150 years.

  • Pollutant levels have increased and show no signs of abatement.
  • Fish stocks have depleted in localised areas.
  • Up to 70-80% of wetlands have been lost in most of the major river catchments adjacent to the Great Barrier Reef.
  • Nutrients such as phosphate and nitrogen have increased by 200-1500% in river discharges.

As a result the Great Barrier Reef is now under pressure - from fishing, from farming, from coastal development, from land-based pollution and simply from overuse. Some significant species are having difficulty adapting to these changing conditions and have now become rare or threatened. These trends are worrying indications of what may happen to other species and habitats of the Great Barrier Reef.



Baby Greenback Turtle
Just hatched! Baby Greenback Turtle
on the way to the water

Marine Turtles

Six of the seven species of marine turtles in the world are found on the Great Barrier Reef. All six species are threatened. An estimated 1750 turtles are caught in trawl nets each year.

  • The Queensland population of loggerhead turtles are facing extinction
  • 70-90% population decline in numbers over the last 30 years
  • 14% of turtles caught in trawl nets are loggerhead turtles
  • Average size of nesting female green turtles has been reducing over last 20 years
  • Analysis of 10 years nesting data of hawksbill turtles shows a downward trend in numbers of breeding females


  • Over 90% decline in Dugong numbers south of Cooktown since the 1960's.
  • Dangerous organo-chlorine pesticide residues have been found in dugong and dolphins.
  • The Great Barrier Reef remains one of the last areas in the world with viable populations of dugongs.


  • Michaelmas Cay has seen a 25% decline in population of Crested Tern and Sooty Tern and a 45% decline in Common Noddy Tern population since the 1980s

Next -  What can I do to help protect the Great Barrier Reef?  

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Pressure on the Great Barrier Reef
Pressure on marine turtles, dugongs, seabirds
What can I do to help protect the Great Barrier Reef?
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