The National Marine Science Centre hosted a Coral Bleaching Workshop on Thursday 27th October. Nicola Fraser, Ian Shaw and Bob Edgar attended as SURG representatives and the results of SURG’s series of coral health surveys were among the presentations on the day. Scientists from institutions including James Cook University, the University of Queensland, Southern Cross University, University of Sydney, and NSW DPI compared notes about the recent coral bleaching event.
The outlook for the far northern region of the GBR is bleak. Professor Terry Hughes and a research assistant from JCU spent over 75 hours in light planes and helicopters over more than 9000 k’s of the GBR taking video of hundreds of reefs. Over 90% of the reefs from Cairns north to the Torres Strait islands were affected.
Many of the older, and usually less susceptible Porites corals were found to be affected when ground truthing of their aerial results was carried out. This is particularly disturbing as the bleaching events are predicted to become more frequent, seriously compromising the ability of faster growing types of coral to recover, let alone the slower growing families.
South of Townsville the situation is slightly better and offshore locations such as the Swain Reefs were seen to be relatively unaffected. In the far north a lot of the corals died in March of this year when the water temperature became so high they ‘cooked’ and then those left alive starved over a relatively short time. Others became compromised and then fell prey to other predators such as COTS and the small mollusc, Drupella, which eat the live coral tissue.
Since the first sign of bleaching was noticed further south, other teams from UQ, University of Sydney, SCU and SURG started investigations and surveys from Flinders Reef north of Moreton Island south to Black Rock near South West Rocks.
Extensive surveys were carried out in the Solitary Islands by a number of different research institutions, with follow up surveys being carried out as late as last week. At the workshop, before and after photographs were shown of some Turbinaria type corals previously affected and recovery and are still alive. Researchers did note a lot of mechanical damage to larger plate corals at North West Solitary due to the storms and rough seas in May and June this year.now mostly recovered, and the general consensus was that the overall effect in the southern areas is likely to be less severe than first thought.
Pocilloporas are still badly affected but some showed signs of recovery and are still alive.
Researchers did note a lot of mechanical damage to larger plate corals at North West Solitary due to the storms and rough seas in May and June this year.
Dr Hamish Malcolm, workshop convenor and Research Scientist with the NSW DPI has had temperature data loggers at various inshore and offshore sites throughout the SIMP as well as at Julian Rocks, for up to 15 years. The loggers record the water temperature at 30-minute intervals and data show a range of temperatures from around 15 degrees to over 27 degrees, which has been recorded at North Solitary Island a number of times. The maximum temp recorded was 27.57 in 2015, at North Solitary, but for the first time since the data collection commenced inshore and midshore reefs also recorded over 27 degrees in March 2016, no doubt influencing the amount of bleaching seen locally.