Double threat may be costly
MORE than a million crown of-thorns starfish have been culled on the Great Barrier Reef in four years, but there are fears it may not be enough to undo damage wrought by another coral threat.
WWF Australia yesterday released a new report written by Cairns-based marine biologist Udo Engelhardt, which claims the fourth record outbreak of the starfish across the marine park has become much more widespread than previous outbreaks, with up to a 50 per cent increase in the number of reefs affected.
Dr Engelhardt, the director of consultancy Reef care International, said he was concerned about the double whammy of COTS outbreaks occurring straight after bleaching, which may leave the natural wonder unable to recover.
“This is the worst-case scenario, because you’re losing those few corals that are showing signs of adaptation to climate stress,” he said.
“If you lose those due to starfish predation, you’ve lost your insurance policy down the track.
“If we improve water quality, we have every chance of reducing this ongoing cycle of COTS outbreaks and therefore give the Reef a fighting chance.”
The report has also recommended COTS monitoring be scaled up and include fine scale surveys, which find juvenile starfish hiding during the day, in order to detect an outbreak up to two years before it develops.
Association of Marine Park Tourism Operators boss Col McKenzie, whose organisation has been implementing the COTS control program, did not believe the current starfish outbreak was any worse than reef infestations during the early 2000s.
He estimated the current tally was up to a million starfish being culled since the program, in its current form, began in 2015.
“We’ve got seven vessels out there, being funded by the Federal Government, to do the work, when in 2000, we only had one,” he said.
He said the current outbreak had shifted between Cairns and Townsville, where eradication efforts in 2019 would be focused.
“The agricultural sector has done an amazing amount of work in improving water quality over the last five years,” he said. “They’ve been pretty responsive to reducing the amount of fertiliser used and I’m not saying we can’t do better, but we are doing a lot better now than what we were doing five years ago.”