Cycles of decline and recovery of inshore island coral reefs

Coral reefs and fish communities around the inshore islands of the Great Barrier Reef Marine Park are vital for tourism and recreational fishing. However, their proximity to land makes them more vulnerable to human impacts, particularly land-based runoff.

Long term monitoring shows inshore island coral reefs have seen declines in coral cover, fish abundance, and diversity, due to coral bleaching, cyclones, and floods. While these reefs can recover if given time between impacts, climate change is increasing the frequency and intensity of such disturbances making it harder for these ecosystems to recover.

Our long-term monitoring tracks inshore island coral reef health, measuring the effects of disturbances and observing recovery. This data is crucial for marine managers due to the high vulnerability and heavy use of island reef habitats.

How the inshore monitoring program informs management

Our 25-year inshore monitoring program has been instrumental in documenting declines and recovery in coral cover, fish abundance, and fish diversity following disturbance events such as coral bleaching, cyclones and floods.

We aim to provide managers with critical information on the impacts of disturbance events and subsequent recovery patterns to help inform targeted intervention and management strategies.

Under the monitoring program, our scientists investigate both coral reef habitats and fish communities:

Coral reef habitats

• Conduct routine in-water surveys to assess the cover of corals, algae, rock, rubble, and sand.

• Track changes in the structural complexity of reefs.

• Gather critical data on disturbance impacts and recovery patterns.

• Monitor recovery rates of coral reefs to identify reasons for slower recovery.

• Inform targeted intervention and management strategies for reef protection.

Fish communities

• Investigate the effects that changes in coral reef habitats have on fish communities over time.

• Monitor the abundance, size, and diversity of reef fish species at reefs open and closed to fishing.

• Assess effectiveness of no-take marine reserves (green zones) in protecting fish species.

• Inform targeted intervention and management strategies for the protection of reefs and important fisheries species.

What islands do we monitor?

Our inshore monitoring program focuses on coral reefs at 43 inshore islands in the Great Barrier Reef Marine Park. The program spans eight key locations from the Turtle Group in the far north to the Keppel Islands in the southern Great Barrier Reef.

Islands monitored for 25 years:

• 30 sites at three islands in the Palm Islands.

• 8 sites at Magnetic Island.

• 42 sites at ten islands in the Whitsunday Islands.

• 30 sites at ten islands in the Keppel Islands.

New islands monitored since 2022:

• 15 sites at six islands in the Turtle Group National Park.

• 12 sites at four islands in the Frankland Islands.

• 2 sites at the Family Islands, off Mission Beach.

• 18 sites at the Cumberland Islands, off Mackay.

Future directions and funding challenges

Our 25-year inshore monitoring program has been instrumental in documenting declines in coral cover, fish abundance and fish diversity – providing critical data for targeted management and conservation strategies.

Despite these critical achievements, this long-term monitoring program faces a lack of funding. Consistent, ongoing monitoring is essential in identifying the status and trends in the health of coral reefs over time, and without it, our understanding and ability to manage these ecosystems will be compromised.

Continued support is essential to maintain and expand our efforts to protect the Great Barrier Reef's valuable coral reef ecosystems.