Emerging Threats from the Fifth COTS Outbreak

A new outbreak of crown-of-thorns starfish (COTS, scientifically known as Acanthaster planci) is gaining momentum along a 240-kilometer stretch between Cairns and Lizard Island on Australia's iconic Great Barrier Reef (GBR). This fifth major wave, potentially one of the worst in six decades, comes ahead of the typical 17-year cycle and coincides with ongoing suppression of the previous outbreak that began in 2010. Each adult COTS devours coral equivalent to a dinner plate daily, contributing to up to 40% of long-term coral loss as documented by long-term monitoring.

Experts warn that without intensified efforts, this could severely impact high-diversity coral areas vital for tourism, supporting a $9 billion annual economy and thousands of jobs in Far North Queensland. The Great Barrier Reef Marine Park Authority (GBRMPA) has mobilized six dedicated vessels, but chief scientist Roger Beeden emphasizes the need to double operations amid this 'build-up' phase.

Understanding the Crown-of-Thorns Starfish Menace

The crown-of-thorns starfish is a large, spiny marine invertebrate native to Indo-Pacific coral reefs, characterized by its venomous spines and distinctive crown-like appearance. Growing up to 30-40 cm in diameter, adults feed voraciously on live coral polyps, stripping tissue and leaving white skeletons that become rubble during outbreaks—defined as 15 or more COTS per hectare. A single female can release over 100 million eggs annually, with larvae dispersing via ocean currents to initiate new infestations.

Outbreaks are exacerbated by human factors: overfishing of natural predators like giant triton snails and triggerfish, plus nutrient runoff fueling larval survival. On the GBR, four prior outbreaks since the 1960s have devastated vast areas, reducing coral cover by up to 90% locally.

The GBRMPA COTS Control Program: Proven Impact

Launched in 2012, the GBRMPA-led Crown-of-Thorns Starfish Control Program employs targeted surveillance and manual culling across priority reefs. Divers use manta tow surveys to detect outbreaks, followed by Reef Health Impact Surveys (RHIS) for precise mapping. COTS are injected with bile salts or vinegar to dissolve their digestive systems.

In 2024-25 alone, the program actioned 234 reefs, culled 73,881 starfish across 11,710 hectares, and conducted 18,282 manta tows with 18,008 diver hours. Since inception, it has removed nearly 1.4 million COTS from 451 reefs, protecting over 830,000 hectares and boosting coral cover by 44% in treated areas. Cumulative costs exceed $25 million yearly, but returns are high with reduced coral mortality up to sixfold.

• Surveillance: Manta tows classify reefs (No Outbreak to Severe).
• Culling: SCUBA divers target crevices, achieving high catch per unit effort (CPUE).
• Prioritization: High-value reefs near tourism sites.

Challenges in Scaling Manual Control Efforts

Despite successes, manual culling is labor-intensive, requiring thousands of diver hours amid venomous spines and vast reef expanses. Vinegar injections can induce spawning in males, risking further outbreaks, while locating hidden juveniles remains difficult. Emerging outbreaks like the current northern surge demand vessel repositioning without neglecting southern hotspots like Swain Reefs.

Climate change compounds pressures, with heatwaves and cyclones hindering recovery, underscoring the need for innovative tools.

Photo by Karl Hedin on Unsplash

James Cook University: Optimizing Injection Toxins

Researchers at James Cook University (JCU), a leader in tropical marine science, published findings in December 2025 showing bile salts outperform vinegar. Led by Professor Morgan Pratchett and Dr. Peter Doll, the study tested toxins on adult COTS during summer spawning. Bile killed males within 24 hours and females in 24-48 hours without inducing spawning—critical as one male can trigger mass events producing millions of eggs.

Vinegar risks prompting reproduction, so bile is recommended seasonally. This refines GBRMPA protocols, enhancing efficiency. For aspiring marine biologists, JCU offers hands-on research opportunities; explore higher ed career advice or research jobs in Australia.

University of Queensland: Modeling Control Benefits Amid Warming

A July 2025 University of Queensland (UQ) study modeled 3,806 GBR reefs to 2040, integrating COTS control, heat stress, and cyclones. Led by Dr. Tina Skinner and Professor Peter Mumby from UQ's School of the Environment, it found control increases coral cover in 85% of reefs, with one-third gaining over 10%. Benefits extend via larval dispersal, persisting despite warming.

Applied to <10% of reefs, it drives system-wide resilience. UQ's work highlights academic contributions to policy. Interested in such modeling roles? Check research assistant jobs.

Breakthrough Publication: Synthetic Pheromones from UniSC and AIMS

The most promising innovation stems from a June 2025 iScience paper by University of the Sunshine Coast (UniSC) Professor Scott Cummins, AIMS Dr. Cherie Motti, and OIST Professor Noriyuki Satoh. Using genomics and proteomics, they identified peptides secreted via COTS spines for communication, possibly swarming.

Synthetic versions ('Acanthaster attractins') lured adults in flume trials at AIMS National Sea Simulator, altering trajectories at low, non-toxic doses. Prof. Cummins notes: 'This could enable simultaneous removal of many starfish in one sweep.' Part of the government-funded COTS Control Innovation Program (CCIP).

How Pheromone Lures Promise Scalable Control

COTS detect peptides olfactorily, aggregating for easier culling—contrasting individual hunts. Lab results show predictable responses, with hydrodynamic models optimizing deployment. Challenges include reef chemical noise, but field trials are imminent along GBR. This semiochemical approach, eco-friendly, could transform pest management.

Photo by David Clode on Unsplash

• Identification: Spine-secreted peptides via omics.
• Trials: Behavioral changes in controlled flows.
• Deployment: Bait stations timed with currents.
• Benefits: Cost/labor reduction, higher cull rates.

Broader Research Ecosystem and Future Outlook

Australian universities drive CCIP alongside AIMS and GBR Foundation, exploring eDNA detection, robot divers, and predator conservation. Public support for novel methods like semiochemicals is high per 2024-25 surveys. With fifth outbreak looming, integrating these could protect World Heritage status.

For marine science careers, institutions like JCU, UQ, and UniSC offer postdocs and faculty roles. Visit Australian academic jobs, postdoc positions, or postdoc advice.

Implications for Reef Resilience and Higher Education

COTS control not only curbs loss but aids adaptation to warming, buying time for resilient corals. Research underscores interdisciplinary needs: molecular biology, ecology, modeling. AcademicJobs.com connects talent to these vital roles, from research assistants to professors shaping ocean futures. Explore rate my professor or higher ed jobs today.