Coral monitoring

We have monitored coral within the Great Barrier Reef World Heritage Area with James Cook University since 2006. Coral communities are a critical coastal marine habitat and a key indicator of overall marine health. We currently survey over 3km of paths each year across five inshore islands near our three east coast ports.

In the dashboard below you can view coral data from the past ten years.

We monitor diversity and abundance of corals and algae; extent of juvenile recruitment (baby corals); and indicators of coral health such as incidence of bleaching, disease and sediment deposition. This long-term data set can be used to help understand the dynamics and resilience of inshore coral communities and to support coastal resource management of our waterways.

Our twice-yearly coral surveys are undertaken by scientists at James Cook University (JCU). Through JCU and NQBP's higher education partnership, our monitoring program has the potential to support wide-ranging research opportunities.

Our coral data also feeds into broader Great Barrier Reef and regional report cards, including the Healthy Rivers to Reef Report Card, which measure the inshore health and resilience of coral communities and define their regional condition across catchments. You can read more on how we monitor coral including how divers collect data.

More information on the broader reef health is available at the Great Barrier Reef Marine Park Authority website.

What makes up a coral community

At each of our monitoring sites, benthic (seafloor) cover is classified into categories of cover type. The data we collect here provides information on the dominant reef structure (hard or soft), as well as the extent of macroalgae and sponges. Knowing the proportion of macroalgae and sponges is important for understanding the condition of the coral community.

Click on the images to learn more about the different coral and other cover types.

  • We survey transects (paths) across each of our island communities in the Mackay and Hay Point region, both pre and post-wet season. The inshore communities have been monitored since 2006. Keswick Island monitoring was also completed from 2015 until 2020 where data confirmed this location as more representative of mid-shelf reefs compared to inshore coral communities. At each transect, benthic (seafloor) cover is classified into categories of cover type and provides information on the dominant reef structure (hard or soft), as well as the extent of macroalgae, which can impede the growth of corals. Information on the extent of bleached, diseased or damaged corals is also determined, which provides information on the health of the coral community. Click below on each monitoring location.

    Monitoring Locations
    Keswick Island
    • Macroalgae cover, known to impact the health of coral communities, has remained relatively stable over time. Coral cover, also stable, comprises typical mid-shelf reef communities and the associated clearer water quality.

      Mean percentage of Benthic Composition

    • Presence of disease in the inshore coral communities of Mackay and Hay Point has fluctuated over 13 years of monitoring. Bleaching, however, has only been recorded alongside accumulated sea surface temperature peaks, such as in 2020.

      Mean density of affected coral colonies per 40 square metres

    Slade Rock
    • Slade Island has shown a steady drop in hard coral cover, with notable reductions following tropical cyclones (2010 and 2017) and significant regional heat stress event (2020). Reductions in macroalgae were also recorded (2020 and 2022).

      Mean percentage of Benthic Composition

    • Presence of disease in the inshore coral communities of Mackay and Hay Point has fluctuated significantly over 13 years of monitoring. Bleaching, however, has only been recorded alongside accumulated sea surface temperature peaks, such as in 2020.

      Mean density of affected coral colonies per 40 square metres

    Round Top Island
    • Round Top Island has the highest soft coral community of all inshore locations monitored. Total coral cover has remained consistently between 25-35%. Reductions in macroalgae (2020 and 2022) were recorded alongside GBR-wide heat stress events.

      Mean percentage of Benthic Composition

    • Presence of disease in the inshore coral communities of Mackay and Hay Point has fluctuated significantly over 13 years of monitoring. Bleaching, however, has only been recorded alongside accumulated sea surface temperature peaks, such as in 2020.

      Mean density of affected coral colonies per 40 square metres

    Victor Island
    • Victor Island held a steady hard coral cover (around 30%) until TC Debbie (2017), which saw a sharp drop accompanied by a rise in macroalgae. Further losses followed the 2020 heat stress event however recent monitoring has tracked potential recovery.

      Mean percentage of Benthic Composition

    • Presence of disease in the inshore coral communities of Mackay and Hay Point has fluctuated significantly over 13 years of monitoring. Bleaching, however, has only been recorded alongside accumulated sea surface temperature peaks, such as in 2020.

      Mean density of affected coral colonies per 40 square metres

    1. Y-axis max differs between indicators of health and benthic composition charts.2. SEs (standard errors) can be accessed in the full reports on our reports and research page.3. Indicators of health chart represents pre-wet survey dates only, full survey data can be found in reports download.4. Small sponge readings up to approx 0.3 % may not be visible. Please refer to the downloadable data file. 5. An adjusted monitoring program design was implemented in Oct 2020 at Holbourne Island, resulting in a rearrangement of site locations to provide a more representative spread of coral cover and community assemblage. Pre-October 2020 results shown in graphs are therefore not directly comparable and may show increased variability in trends initially. Further details of these changes can be seen in the full reports.6. This same review (Oct 2022) resulted in a reduction from 6 to 4 sites per island for Hay Point and Mackay. Pre-October 2020 results shown in graphs will therefore not be directly comparable however this is not considered to have a measurable impact for the purpose of this display.7. Monitoring at Keswick Island ceased in 2020 after data confirmed this location as more representative of mid-shelf reefs compared to inshore coral communities.

    Coral and Benthic Cover at Hay Point & Mackay

    Inshore corals and benthic (sea floor) cover are, to an extent, naturally acclimatised to greater frequency and scale of disturbances like cyclones, high water temperatures, and freshwater influx and elevated turbidity (sediment in water) from flooding compared to their more offshore counterparts. Measuring coral cover, alongside diversity, juvenile recruitment, and bleaching and disease, can help us to understand the typical degree of change in these communities, anticipate recovery potential and timeframes from such disturbances.

    What the chart shows

    Over the past 12 months, hard coral cover has begun to increase in the three inshore locations following the most recent major disturbance from accumulated sea surface temperature heat stress at the GBR-wide scale in 2020.

    Read more on cyclone impacts on the coral near our ports. You can see more analysis on the data in these reports.

    Hard coral cover at Hay Point & Mackay

    1. Y-axis is dynamic and therefore differs between each tab.2. SEs (standard errors) can be accessed in the full reports on our reports and research page.3. Pre and post wet season annual surveys commenced in 2015.4. Holbourne Island sites were rearranged in October 2020 therefore prior results shown in graphs are not directly comparable and may show increased variability in trends initially. Further details of these changes can be seen in the full reports.5. This same review (Oct 2022) resulted in a reduction of sites per island for Hay Point and Mackay. Pre-October 2020 results shown in graphs will therefore not be directly comparable however this is not considered to have a measurable impact for the purpose of this display.

    What the chart shows

    Soft corals have never been common in the inshore islands monitored (historically ranging from 2% to 10% of cover); however, they have consistently been significantly more abundant on Round Top and Keswick. Being a mid-shelf reef, Keswick has since been removed from the monitoring program however Round Top remains the most abundant for soft corals, these most recently accounting for approximately 7% of cover.

    Read more on cyclone impacts on the coral near our ports. You can also see more analysis on the data in these reports.

    Soft coral cover at Hay Point & Mackay

    1. Y-axis is dynamic and therefore differs between each tab.2. SEs (standard errors) can be accessed in the full reports on our reports and research page.3. Pre and post wet season annual surveys commenced in 2015.4. Holbourne Island sites were rearranged in October 2020 therefore prior results shown in graphs are not directly comparable and may show increased variability in trends initially. Further details of these changes can be seen in the full reports.5. This same review (Oct 2022) resulted in a reduction of sites per island for Hay Point and Mackay. Pre-October 2020 results shown in graphs will therefore not be directly comparable however this is not considered to have a measurable impact for the purpose of this display.

    What the chart shows

    Four extreme cyclonic weather events impacted these inshore island locations in the 10 years between 2012 and 2022. In this same time period, these locations have also experienced two GBR-wide bleaching events aligning with accumulated sea surface temperature peaks – more information on the broader reef health and coral bleaching is available at the Great Barrier Reef Marine Park Authority website.

    These extreme cyclonic weather events not only had significant effects on hard coral cover but also preceded a marked increase in macroalgae at all locations. In contrast, macroalgae at all locations dropped off during the GBR-wide bleaching accumulated sea surface temperatures in 2020.

    You can see more analysis on the data in these reports.

    Macroalgae cover at Hay Point & Mackay

    1. Y-axis is dynamic and therefore differs between each tab.2. SEs (standard errors) can be accessed in the full reports on our reports and research page.3. Pre and post wet season annual surveys commenced in 2015.4. Holbourne Island sites were rearranged in October 2020 therefore prior results shown in graphs are not directly comparable and may show increased variability in trends initially. Further details of these changes can be seen in the full reports.5. This same review (Oct 2022) resulted in a reduction of sites per island for Hay Point and Mackay. Pre-October 2020 results shown in graphs will therefore not be directly comparable however this is not considered to have a measurable impact for the purpose of this display.
  • We survey transects (paths) across each of the two island communities in the Abbot Point region, both pre- and post-wet season. At each transect, benthic (seafloor) cover is classified into categories of cover type and provides information on the dominant reef structure (hard or soft), as well as the extent of macroalgae, which can impede the growth of corals. Information on the extent of bleached, diseased or damaged corals is also determined, which provides information on the health of the coral community. Click below on each site.

    Monitoring Locations
    Camp Island
    • Camp Island is dominated by macroalgae declining most significantly post-Tropical Cyclone Debbie. Hard coral cover was generally unaffected. The bleaching event (2020) reduced macroalgae and led to a significant loss of hard corals (2019 to 2021).

      Mean percentage of Benthic Composition

    • The 2018 and 2019 pre-wet surveys showed no evidence of bleaching due to the comparatively mild accumulated heat stress recorded. Elevated temperatures in early 2020, however, contributed to a significantly high occurrence of bleaching. Damage from predation and disease, whilst low levels, has also been consistently recorded.

      Mean density of affected coral colonies per 40 square metres

    Holbourne Island
    • Holbourne Island has comparatively very low macroalgae cover; however, TC Debbie was shown to have had a devastating impact on coral cover, with a loss of more than 75% of coral cover. Recovery of these communities remains, to-date, negligible.

      Mean percentage of Benthic Composition

    • The 2018-19 summer sea surface temperatures and accumulated heat stress were significantly milder than levels in 2016-17. Hence, the 2018 and 2019 pre-wet surveys show no evidence of bleaching. Elevated temperatures in early 2020, however, contributed to a comparatively high occurrence of bleaching. Damage from predation and disease has also been consistently recorded at Holbourne Island.

      Mean density of affected coral colonies per 40 square metres

    1. Please note y-axis max differs between indicators of health and benthic composition charts.2. SEs (standard errors) can be accessed in the full reports on our reports and research page.3. Indicators of health chart represents pre-wet survey dates only, full survey data can be found in reports download4. Note: Small sponge readings up to approx 0.3 % may not be visible. Please refer to the downloadable data file.

    Coral and Benthos Cover at Abbot Point

    Inshore corals and benthic (seafloor) cover are, to an extent, naturally acclimatised to greater frequency and scale of disturbances like cyclones, high water temperatures, and freshwater influx and elevated turbidity (sediment in water) from flooding compared to their more offshore counterparts. Measuring coral cover, alongside diversity, juvenile recruitment, and bleaching and disease, can help us to understand the typical degree of change in these communities, anticipate recovery potential and timeframes from such disturbances.

    What the chart shows

    Surveys at Abbot Point commenced in 2016. A clear impact from Tropical Cyclone Debbie was shown 18 months later at Holbourne Island, which was most affected, given the cyclone's trajectory. Holbourne Island has struggled to recover from these impacts and has been predated consistently by crown-of-thorns starfish.

    Camp Island hard coral communities were somewhat protected and have shown strong recovery since 2017. The 2020 summer bleaching event was found to significantly affect corals at all locations and signs of recovery at Camp Island have since been observed.

    Holbourne Island sites were revised in 2020 and therefore trends shown are not temporarily comparable. Changes since October 2020 show consistent increases in hard coral cover.

    You can see more analysis on the data in these reports.

    Hard coral cover at Abbot Point

    1. Please note y-axis is dynamic and therefore differs between each tab.2. SEs (standard errors) can be accessed in the full reports on our reports and research page.

    What the chart shows

    Surveys at Abbot Point commenced in 2016. A clear impact from Tropical Cyclone Debbie was shown 18 months later at Holbourne Island, which had considerable soft coral cover prior to this and has struggled to recover since.

    Soft coral cover has been slow to recover with very little change since TC Debbie declines in 2017. Camp Island communities however have never recorded high percentages of soft coral cover, being dominated by hard corals.

    You can see more analysis of the data in these reports.

    Soft coral cover at Abbot Point

    1. Please note y-axis is dynamic and therefore differs between each tab.2. SEs (standard errors) can be accessed in the full reports on our reports and research page.

    What the chart shows

    Holbourne Island is a more mid-shelf location than Camp Island and reefs around this island did not show high levels of macroalgae.

    Camp Island was found to have much higher macroalgae cover at 49% during the same survey period. These high macroalgae levels are thought to be influenced by seasonal nutrient fluctuations. The peak of 76% in October 2020 followed the GBR-wide bleaching events of early 2020. In the Mackay and Hay Point region macroalgae was seen over this same period to decline significantly.

    You can see more analysis on the data in these reports.

    Macroalgae cover at Abbot Point

    1. Please note y-axis is dynamic and therefore differs between each tab.2. SEs (standard errors) can be accessed in the full reports on our reports and research page.

Marine monitoring at NQBP

We conduct a wide range of marine monitoring at our ports and in the surrounding Great Barrier Reef World Heritage Areas year-round.

Watch dive surveys in action

NQBP undertakes a comprehensive ambient marine monitoring program, looking at a variety of elements including seagrass, coral and water quality.

Extensive ambient marine environmental monitoring of water quality, coral and seagrass by our environmental partners James Cook University and TropWATER assist us to ensure risks to the environment are managed and ship trade continues in and out of our ports.

Watch JCU scientists in action on the reef while completing monitoring in our Port waters off Mackay.