The Reef Authority's Crown-of-thorns Starfish (COTS) Control Program will re-deploy resources to protect priority reefs in the Northern region over the next 12-months, with field intelligence confirming that the current COTS outbreak is intensifying on reefs between Cairns and Lizard Island.
More than 50 Reef managers, scientists, COTS Control Program operators and tourism industry partners met today in Cairns to prioritise reefs for inclusion in the COTS Control Program's 2026-27 Annual Work Plan.
Assistant Director of the COTS Control Program, Dr David Williamson said the workshop is a valuable opportunity for all partners to proactively review and refine target reefs ahead of the new Financial Year.
"This workshop is a critical step in the development of the Program's Annual Work Plan and underpins the work we do on the Reef to deliver broadscale outbreak suppression and coral protection outcomes," Dr Williamson said.
"Over the past few years, we have been increasing COTS control capacity in the northern GBR to supress the emerging primary outbreak, while maintaining scaled-down control efforts in the Central and Southern regions," Dr Williamson said.
"We expect that the Northern outbreak will continue to intensify during the next few years. With the majority of our partners represented at today's workshop, we will be examining the field intelligence and model predictions that inform our decision-making for COTS Control Program operations.
"The knowledge being shared at this workshop helps to ensure that COTS Program vessels and dive teams are actioning the right reefs at the right times to maximise outbreak suppression and coral protection outcomes."
Adult COTS can grow larger than the size of a dinner plate and consume their body size in coral every day or two.
Funded by the Australian Government, the COTS Control Program currently deploys six vessels, each with teams of six to ten divers who cull the starfish using a lethal single-shot injection of household vinegar or ox bile salt solution.
Roberto Tusso, Operations Manager at COTS contractor Blue Planet Marine, said the Program's proactive and systematic approach is critical.
"On the water, we see firsthand how quickly crown-of-thorns starfish can impact coral," he said. "If outbreaks intensify, COTS become much harder to control. Timing and coordination, punctuated by sharing on ground information through forums like these reef prioritisation workshops and our regular operations group meetings, are the key to effective COTS control.
"The earlier we act, the more Reef we can protect."
Fast facts
- Crown-of-thorns starfish (COTS) are a native species on the Great Barrier Reef, instantly recognisable by their long, venomous spines.
- They are the world's second-largest starfish, capable of growing to almost one metre in diameter, and with spines coated in a toxic slime.
- Natural predators include fish species such as emperor, snapper, coral trout, tuskfish and Māori wrasse, triggerfish, pufferfish, and the giant triton snail.
- A single mature female can release at least 200 million eggs a year.
Causes of outbreaks are not entirely known but could result from a combination of:
- Excess nutrients from run-off and natural upwelling supporting increased larval survivorship
- Availability of live coral to eat
- Ocean currents that spread larvae across the Reef, and
- Removal of natural predators.
COTS Control Program overview
- Strong partnerships, science integration, robust field intelligence and decades of Reef tourism industry site stewardship and culling experience underpin the success of the COTS Control Program.
- Since 2012, the Program has delivered over 160,000 diver hours, removing almost 1.4 million coral-eating starfish across 451 reefs, protecting more than 830,000 hectares of Reef habitat.
- The Program employs around 140 people, including 14% Indigenous staff, and delivers targeted training, traineeships and capacity-building for tourism crews and First Nations communities.
- It protects coral on high-value tourism reefs that account for over 95% of all Reef tourism visitation.
- The program is funded 2022-2030 at around $20 million per year under the $161.5 million COTS Control investment in the Australian Government's Reef Protection Package.
