Picture: Coral in the Southern Barrier Reef by Ana Urrutia.

Surveyed reefs in the Capricorn Bunkers have lost 41 per cent of their hard coral cover according to the latest Australian Institute of Marine Science (AIMS) underwater research.

 

November surveys show significant hard coral death on the southern reef – a month after survey results showed similar results on northern section. This region includes some of the jewels of the Reef’s crown, including popular tourist sites such as Heron Island, Lady Elliot Island and Lady Musgrave Island.

 

Survey results from 1 to 11 November 2024:

  • Eight reefs were surveyed in the Capricorn-Bunker sector: Broomfield Reef, Wreck Island, Erskine Island, Masthead Island, One Tree Island, Hoskyn Reef, Fairfax Island, and Lady Musgrave Island.
  • Live hard coral cover decreased substantially on seven reefs due to the 2024 mass coral bleaching event, storm swell, and coral disease.
  • These disturbances have caused the single largest annual decline in hard coral cover of this sector since surveys began. Coral cover in this sector was on average 56.2 per cent before summer, and is now 32.95 per cent cover post-summer. This is a relative 41 per cent decline in coral cover.
  • A Severe Outbreak of Crown-of-thorns starfish (COTS – Acanthaster cf. solaris) was recorded on One Tree Island, the first time such a density of COTS has been recorded at this reef. Feeding scars were present on four reefs.\
  • Low levels of coral bleaching were recorded on the reef slope in November 2024 (≤5 per cent of corals for all reefs).

The Australian Marine Conservation Society (AMCS) said the AIMS Long Term Monitoring Program (LTMP) underwater surveys found substantial death of corals in the Capricorn Bunker region, with a 41 per cent loss of coral cover, which is the largest annual decline for this sector since the LTMP began. AMCS Great Barrier Reef Campaigner Simon Miller said the severe bleaching event seen earlier in 2024 has caused the single largest annual decline in hard coral cover on the southern section of the Great Barrier Reef since surveys began. “The Reef faces another summer from hell with heat already building up in the water and coral bleaching warnings for much of the northern Reef, with temperatures already 0.5-1OC above average,” Ms Miller said.

“Our Great Barrier Reef is enduring more frequent and intense bleaching events, one after another with insufficient time to recover, which can take more than a decade. “We know what needs to be done to help give the Great Barrier Reef a fighting chance. Australia must urgently commit to more action to battle climate change, slashing greenhouse gas emissions and stop approving new fossil fuel developments. “The Australian and Queensland governments need to submit a report to World Heritage Committee advisers UNESCO by February 1, detailing mortality rates from the bleaching event and presenting an updated emissions reduction target.

“The Australian and Queensland governments must also develop a coral bleaching response plan. We need to treat these major events with the urgency they deserve to increase the resilience of Reefs that are being impacted by bleaching and cyclones. The immediate response should include tangible actions such as stopping the harvest of wild corals and focussing on removing crown-of-thorns starfish (COTS) from affected reefs, as well as urgently cutting water pollution and ensuring fisheries are sustainable.”

Reef surveys are still underway, and scientists continue to monitor the impact of the 2024 bleaching event.

This article appeared in CQ Today on 13-01-24