Key environmental pressures
There were limited cyclone impacts experienced in the inshore Reef region in 2021-22, with ex-Tropical cyclone Tiffany being the only to make landfall, in Eastern Cape York. Moderate floods occurred in the Annan-Endeavour, Stewart and Normanby Rivers in the early part of 2022, but more wider-spread flood events were experienced later due to unseasonally high rainfalls.
Sea water temperatures in early 2022 reached levels sufficient to cause coral bleaching (but impacts were mainly limited to inshore reefs in the Burdekin region).
These temperature anomalies were highest in the Burdekin region, tapering toward the Mackay-Whitsunday region and southern areas of the Wet Tropics region.
An active crown-of-thorns starfish outbreak was recorded but limited to the Johnstone Russell–Mulgrave and Barron-Daintree sub-regions in the inshore Wet Tropics.
The large number of these starfish removed by the Reef Authority’s Crown-of-Thorns Control Program has been limiting their impact on the coral condition.
Read the latest Marine Monitoring Program Annual Report 2021-22 - Inshore Coral Reef Monitoring.
How did inshore corals respond?
Reef-wide coral condition for inshore reefs remained in an overall ‘poor’ condition in 2022, the Coral Index having increased marginally from a low point in 2021.
- In the Wet Tropics region:
- Inshore coral communities remain in a ‘moderate’ condition.
- In 2022, the Cover change indicator remained ‘good’, the Coral cover indicator increased to ‘good’, and all other indicators remained ‘moderate’.
- While there were no severe disturbances over this period in this region overall, scores within sub-regions varied as coral communities were impacted by, or recovered from, localised pressures.
- In the Burdekin region:
- inshore reefs remained in an overall ‘poor’ condition in 2022, having improved marginally from a low point in 2021, having experienced thermal stress in early 2020.
- Again, but to a lesser extent, in 2022, thermal stress was sufficient to cause coral bleaching at most reefs.
- Coral cover in 2021 and 2022 continued to increase overall, with the regional average in 2022 being higher than observed since the beginning of this inshore monitoring program in 2005.
- In the Mackay-Whitsunday region:
- This area has improved marginally since 2020, although the condition remained ‘poor’.
- The recent improvement captures early signs of recovery from the severe impact of cyclone Debbie in 2017.
- Sediment resuspension has been an issue in the region, slowing the recovery of those reefs.
- The Juvenile coral indicator increased for the second year in a row (2020-21 and 2021-22 monitoring years).
- In the Fitzroy region:
- Coral condition remained ‘poor’ having improved slightly since 2021.
- The state of reefs varied markedly across the region.
- Coral cover was highest at the reef furthest from the coast, Barren Island.
- The persistent cover of large, brown macroalgae continued to suppress coral community recovery at most other reefs.
What is monitored and where?
Condition and trend of inshore coral communities are surveyed at two and five-metre depths at reef sites located in the Wet Tropics, Burdekin, Mackay-Whitsunday, and Fitzroy regions.
- At these sites, coral monitoring assesses the following indicators:
- coral cover
- proportion of macroalgae
- juvenile coral density
- rate at which coral cover changed
- coral community composition (genus level)
Additionally, signs of bleaching, disease, physical scars, and any other damage are recorded.