a snorkeller underwater being pulled by a rope, hanging on a a yellow board.

Long-Term Monitoring Program

The most comprehensive and extensive record of coral status on any reef ecosystem

AIMS' Long-Term Monitoring Program measures the status and trend of reefs in the Great Barrier Reef World Heritage Area.

Each year, our team of marine scientists spend more than 120 days at sea surveying between 80 and 130 reefs along the length and breadth of the Reef. Over its 35+ year history, the Program has surveyed more than 490 reefs, across a range of environmental gradients within the Reef - for example, across gradual changes in water clarity, wave energy and latitude. We also monitor in different management zones.

The result is the most comprehensive and extensive record of coral status on any reef ecosystem in the world.

The data are an essential resource for governments, the science community and everyone involved in its management and protection. 

An AIMS marine scientist is towed around the perimeter of a reef during monitoring

The importance of large-scale, long-term data

The Great Barrier Reef is a large dynamic system, 1.5 times larger than Victoria and roughly the size of Germany.Its condition varies among reefs and regions, and changes through time in response to disturbances.

Coral reefs undergo cycles of disturbance and recovery, the extent of which differs among regions. These cycles take place over decades meaning that the task of understanding changes on the Reef is complex.

The long term and large-scale data from this monitoring program are collected in a robust, repeatable way and help scientists understand the natural variability of reef populations and is essential for informed management.

From algae to sharks – what we measure

Our monitoring team measure many aspects of coral reef health on surveys:

  • Levels of coral bleaching
  • Numbers of crown-of-thorns starfish
  • Coral disease
  • Juvenile corals
  • Coral-eating snails
  • Reef fish species abundance, diversity, length, and biomass, including commercially important species such as coral trout, and other ecologically important fishes such as herbivores and those closely associated with corals
  • Numbers of sharks.

How we measure

Reef data are gathered through two globally used, standard methods.

Observing entire reefs quickly through manta tow surveys

Manta tow surveys involve towing researchers behind boats to observe the standard reef slope habitat around the perimeter of entire reefs, allowing large areas of reef to be surveyed quickly with minimal equipment. Repeatedly surveying a standard habitat enables scientist to be able to detect changes through time.

These surveys have been used since the Program began in 1983. They identify reef-wide changes in coral cover, and inform managers of the progress of starfish outbreaks, monitor the value of no-fishing zones put in place in 2004, and form the basis of the annual summary report.

Reef survey clip - Middle Banks 2020, Cape Grenville Sector. Great Barrier Reef

Observing detailed changes from fixed site surveys

SCUBA divers survey the reef along permanently marked stretches of reef and are repeated every one or two years. Since 1993, these fixed site surveys have offered detailed information on the animals and plants which make up the reef community, and how they have changed.

The trained observers carry out both photographic surveys of coral communities, as well as visual counts to collect the detailed information on reef fishes, numbers of juvenile corals as well as factors which cause coral death, such as coral predators coral disease and bleaching.

Machine learning for faster, deeper insights

AIMS monitoring is adapting to include innovative technologies aimed at increasing efficiency and providing more insights. These include high-tech computer programs to visualise reefs in 3D, and a machine-learning coral recognition system which speeds up data analysis.

Improving our understanding of the Great Barrier Reef

The Long-Term Monitoring Program is a critical source of data and information on the health of the Great Barrier Reef.

  • It contributes fundamental knowledge about coral reefs, how the Reef works, and how it is changing, and has formed the basis of more than 140 peer-reviewed publications
  • It is used by the Great Barrier Reef Marine Park Authority to inform management decisions regarding the effectiveness of no-fishing zones since 2004 and crown-of-thorns outbreaks
  • The data contribute to the GBRMPA Outlook Report and the Reef 2050 Long Term Sustainability Plan
  • The Program contributes to the Reef 2050 Integrated Monitoring and Reporting Program