Mixed bill of health for the Great Barrier Reef

26 July 2019


Boundaries of Northern, Central and Southern GBR

Figure 1. Boundaries of Northern, Central and Southern GBR used in the trend analyses. Image © AIMS

The Australian Institute of Marine Science (AIMS) has released its annual report for 2018/19 on the health of the Great Barrier Reef (GBR).

This long-term monitoring started in 1985 and clearly demonstrates the impact numerous disturbances including tropical cyclones, coral bleaching and outbreaks of the corallivorous crown-of-thorns have had over the last 5 years. These disturbances have caused declines in hard coral cover across much of the GBR.

2018/19 Summary Report

The GBR has been divided into Northern, Central and Southern regions (see Figure 1). Naturally, the impacts on the GBR have been variable both within and among the various regions.

  • Reefs in the Northern and Central Great Barrier Reef regions have been exposed to multiple disturbances including mass coral bleaching cyclones and the crown-of-thorns starfish.
  • Reefs in the Southern region were not subject to any major disturbances from 2009 up to 2017.
  • In 2017, a massive outbreak of crown-of-thorns occurred and continued through until 2019.

All these events apparently have led to a decline in hard coral cover in the Central and Southern regions while the Northern region has had a slight increase in hard cover. However, the slight increase is still among the lowest levels ever recorded and the results obtained in 2019 may be misleading as, due to safety concerns, most of the inshore reefs could not be surveyed.

The AIMS Long-term Monitoring Program 

The AIMS program provides reef surveys for over 30 years. It demonstrates the dynamic nature of the GBR coral reefs and the considerable variation in recovery and capability to withstand the various weather events as well as anthropogenic and natural threatening processes.

These long-term studies have recorded the ability of the reefs to recover but, as stated in the report, “such resilience clearly has limits”.

The report highlights the challenges faced with the predicted consequences of climate change, high turbidity, changing ocean chemistry and higher ocean temperatures. The combination of the various challenges has resulted in the decimation of breeding populations of coral and, together with the occurrence of more frequent events, there is less time for recovery that results in less living coral on the reefs of the GBR.

There is no question that the funding both the Commonwealth and Queensland governments are providing is assisting in enhancing the quality of the environment for the GBR. Although not all targets are being achieved.

The founding members of Wildlife Preservation Society of Queensland were fighting for the conservation and protection of this iconic wonder – the GBR – 57 years ago and the battle continues today.

The good news is, measuring and understanding the process of coral reef recovery will be a major focus of AIMS research and monitoring over the next years.

The Long-term Reef Monitoring Program – Annual Summary Report on coral reef condition for 2018/19 is available on the AIMS website.


Pin It on Pinterest

Share This