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.

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

Dugong

• 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.

Seabirds

• 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

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