Monitoring in the Great Barrier Reef

Weather station deployed on Davies Reef. (Credit: Marie Roman / AIMS)

An international icon and critical marine ecosystem, the Great Barrier Reef is a cornerstone of the region’s economy, biodiversity, culture, and history. However, anthropogenic stressors and climate change have led to some deterioration of areas of the reef over time, making protecting the reef a challenge for local and global institutions.

The Australian Institute of Marine Science (AIMS) partners with local groups to monitor coral and fish communities, water quality, and sea temperatures to understand the effects of various environmental pressures, including marine heatwaves driven by climate change, cyclones and crown-of-thorns starfish outbreaks.

Why Monitor the Great Barrier Reef

According to an AIMS spokesperson, the Great Barrier Reef contributes an estimated $6 billion annually and supports more than 60,000 jobs, supporting tourism and commercial and recreational fisheries. However, under the changing climate, coral reef health—and the organisms that reside there—have been heavily impacted.

To monitor these changes, AIMS and its partners monitor water quality, climate conditions, and indicators of biodiversity status in the region. The data collected by the various monitoring programs supports marine environmental reporting and decision-making by the government and other stakeholders.

Integrated Reef Fish Monitoring Program on Orpheus Island in May 2024. (Credit: Gus Burrowes / AIMS)

Monitoring Water Quality in the Great Barrier Reef

Water quality monitoring in the reef is of particular importance due to the influence of land-derived runoff, which can deliver large amounts of suspended sediment, nutrients and potentially contaminants to inshore areas of the Reef, including coral and seagrass habitats, especially during high rainfall events. Such influxes can impact the health of these habitats.

Water quality parameters like water temperature, nutrients, suspended solids, chlorophyll a, salinity, water clarity, and turbidity are analyzed from samples collected at set sites along the Reef coast. Monitoring efforts include both discrete sampling and continuous data collection using data loggers along the Reef and river mouths that empty into the Reef.

These conditions are primarily monitored through two programs: the Great Barrier Reef Marine Monitoring Program (MMP) and the Integrated Marine Observing System (IMOS).

The MMP is a collaboration between the Great Barrier Reef Marine Park Authority, the Australian Institute of Marine Science, James Cook University, and the Cape York Water Partnership, with important contributions from Traditional Owners, the Reef Joint Field Management Team, Seagrass Watch, and community volunteers.

Water quality monitoring in the Great Barrier Reef. (Credit: AIMS)

Established in 2005, the program’s goal is to monitor, assess, and report on the health of the inshore Great Barrier Reef. It is focused on understanding the condition and trend of inshore water quality and the status and trend of inshore habitats of the Reef including seagrass meadows and coral reefs.

IMOS uses oceanographic buoys and other oceanographic equipment to monitor the mid-shelf and offshore areas of the reef, maintaining continuous monitoring systems that record temperature, salinity, turbidity, and chlorophyll at selected sites in the Great Barrier Reef.

Additional monthly measurements of chemical and biological variables are also conducted at the Yongala National Reference Station and are added to this data set. Data is freely available to the science community, other stakeholders, and users.

Data from both MMP and IMOS contribute to the Reef 2050 Water Quality Improvement Plan, a joint commitment of the Australian and Queensland governments that focuses on improving water quality flowing into the reef.

Water Quality Research in Northern GBR. (Credit: Marie Roman / AIMS)

Climate Monitoring Efforts in the Great Barrier Reef

Climate change is of particular concern due to potential impacts on coral health. Monitoring of sea temperatures and other Essential Climate Variables can help scientists who study trends in climate conditions. These variables are monitored through networks of weather stations, moorings, temperature loggers, satellite images and other monitoring equipment.

AIMS has been monitoring sea temperature since 1987, and the “resulting research has linked an increase in the frequency of mass bleaching events, coral disease outbreaks and plagues of crown-of-thorns starfish to prolonged exposure to warm sea temperatures.”

Climate monitoring, in particular, is important for reef health as coral and other temperature-sensitive organisms can be killed or bleached during heat waves. This temperature tolerance can vary according to geography, temperature levels, and duration of exposure.

While the corals in the Great Barrier Reef are worth protecting on their own, the health of the Reef overall can positively or negatively impact the fisheries and biodiversity in the region.

Weather station deployed on Davies Reef. (Credit: Marie Roman / AIMS)

Monitoring Great Barrier Reef Biodiversity

Biodiversity monitoring efforts focus on coral fishes and agents of coral mortality like crown-of-thorns starfish. Efforts include manta tow surveys, underwater video stations, and megafauna tracking using acoustic telemetry.

AIMS’ Long-Term Monitoring Program has been measuring the status and trend of reefs in the Great Barrier Reef World Heritage Area for the past 40 years and is one of the most comprehensive and extensive records of coral reef status in the world.

Every year, the AIMS team of marine scientists spend 120 days at sea surveying between 80 and 130 reefs along the length and breadth of the Great Barrier Reef. Many of these surveys are done via manta tow surveys and scuba divers observing detailed changes at fixed sites.

These surveys are designed to collect data in a robust and repeatable way, documenting changes in coral cover, the makeup of seafloor communities, numbers of crown-of-thorns starfish, coral disease and bleaching, juvenile corals, reef fish abundance and diversity, and number of sharks.

Diver conducting a manta tow survey of the Great Barrier Reef. (Credit: LTMP / AIMS)

As a part of the MMP program, AIMS also monitors inshore reefs close to the Queensland coastline with the Reef Authority, which includes measuring seafloor cover of corals, soft coral and macroalgae, as well as juvenile corals and coral disease.

Similarly, the Queensland IMOS project includes the use of acoustic telemetry arrays to monitor tagged rays, sharks, and teleosts along Australia’s east coast.

Collaborators, including universities, government agencies, industry partners, and tourism operators, assisted in installing 119 underwater listening stations and tagging 812 specimens for continuous remote monitoring.

Stations are maintained as part of the national IMOS Animal Tracking Facility, and data is shared publicly to better understand seasonal movements and essential habitat use along the Australian east coast. More specifically, the data informs the State Government SharkSmart guidelines, fishery stock assessment, and marine protected area use.

Finally, the Integrated Reef Fish Monitoring Program was a two-year project between AIMS and Indigenous Ranger groups, government agencies, and universities that sought to promote reliable long-term monitoring data of fish populations by sea Country Ranger groups.

Integrated Reef Fish Monitoring Program on Orpheus Island. (Credit: Gus Burrowes / AIMS)

An AIMS spokesperson stated, “The goal of the program was to fill critical knowledge gaps in under-represented areas and provide a better understanding of inshore habitats, seascape nurseries, and deep-water inter-reef habitats for highly valued fish populations.

AIMS scientists worked with the Mingga Mingga, Yunbenun and Girringun Rangers in developing fish monitoring skills and methods with the help of baited remote underwater video stations in the central GBR.

All of this data is shared with different stakeholders to improve management of the Great Barrier Reef and protect the ecosystem.

The AIMS spokesperson explained, “A better understanding of how fishes might respond to environmental changes through time is gained through data collected on fish diversity and abundance, and broad-scale movements of species of important fishery, conservation and biocultural value.”

Integrated Reef Fish Monitoring Program on Orpheus Island. (Credit: Gus Burrowes / AIMS)

Conclusion

AIMS leads or is a partner on a number of monitoring programs that collect data on different aspects of the Great Barrier Reef, from incoming water quality to bio-physical parameters, reef fishes and coral cover. This information informs management of the Reef.

Changes documented by these monitoring programs help scientists, reef managers and the community better understand the dynamics and resilience of the reefs and support coastal resource management decisions.

AIMS monitoring data provided a demonstration of the effectiveness of the Great Barrier Reef Marine Park Authority’s rezoning of the Reef.

By the late 1990s, it was recognized that the existing no-take marine reserves, which covered only 4.5% of the marine park, were not adequately protecting biodiversity and that many biological communities were poorly protected within these reserves.

(Credit: LTMP / AIMS)

A decision was taken to expand the level of protection to more than 30% of the marine park, with the no-take marine reserves, or ‘green zones’, coming into effect in 2004.

AIMS continues to monitor the impact of the protected areas to confirm they are having the intended effect.

The monitoring data has also been effective at highlighting the success of programs like the Reef Authority’s COTS (crown-of-thorns starfish) Control Program.

“COTS are a major driver of coral loss on the Great Barrier Reef, eating hard coral and decimating colonies when in large numbers,” an AIMS spokesperson stated.

The spokesperson continued, “Starfish densities in some regions were reduced by up to six times with timely and adequate control efforts between outbreaks before and after 2012.”

AIMS is one of many organizations that have been monitoring and protecting the Great Barrier Reef for decades. With existing programs always expanding and new programs filling in knowledge gaps, the ever-growing dataset plays a key role in informing management in the region.

Reef Monitoring. (Credit: Kate Osborne / AIMS)