The Great Barrier Reef is facing a silent yet devastating threat, and it’s one that could reshape this natural wonder as we know it. A new outbreak of crown-of-thorns starfish (COTs) is emerging in the northern region, and scientists are sounding the alarm. If left unchecked, this could become one of the most severe outbreaks in decades, wreaking havoc on the already fragile reef ecosystem. But here’s where it gets even more concerning: this isn’t the first time the reef has battled these coral-eating invaders, and the stakes are higher than ever.
The Great Barrier Reef Marine Park Authority (GBRMPA) has detected a troubling increase in COTs along a 240-kilometer (150-mile) stretch between Cairns and Lizard Island. These starfish, scientifically known as Acanthaster cf. solaris, are native to the region but become a menace when their populations surge. At natural densities—fewer than one starfish per hectare—they’re a normal part of the reef’s ecosystem. However, when their numbers explode, their voracious appetite for coral can outpace the reef’s ability to recover. And this is the part most people miss: a single starfish can produce hundreds of millions of eggs, spreading rapidly with ocean currents, making them incredibly difficult to control.
‘Crown-of-thorns starfish are a natural part of the reef, but when their numbers skyrocket, they can decimate coral,’ explains Roger Beeden, GBRMPA’s chief scientist. Scientists define an outbreak when densities exceed 10 to 15 starfish per hectare. During severe outbreaks, these numbers can soar, leading to widespread coral loss in a matter of months. Since the 1960s, the reef has endured four major outbreaks, with the most recent beginning in 2010 and still requiring management. This new outbreak adds another layer of urgency to an already dire situation.
GBRMPA is responding with intensified monitoring and control efforts, focusing on high-value reefs as part of its Crown-of-Thorns Starfish Control Program. Trained divers are manually removing or injecting starfish with vinegar or cow bile—a method that’s both effective and environmentally friendly. But controlling COTs is no small feat. Their remarkable regenerative abilities and venomous spines make them formidable opponents. Plus, the affected area is a hotspot for tourism, particularly scuba diving, where thousands of dives are conducted annually. The economic and ecological implications are massive.
The Tourism Reef Protection Initiative (TRPI) is playing a crucial role, partnering with tour operators to monitor outbreaks and assist with culling efforts. ‘Protecting the Reef isn’t just about saving coral—it’s about safeguarding livelihoods, tourism jobs, and Australia’s most iconic natural treasure,’ says Gareth Phillips, CEO of the Association of Marine Park Tourism Operators (AMPTO). This collaborative effort between industry, science, and government is a beacon of hope, but it raises a thought-provoking question: Can we strike a balance between human activity and reef conservation, or are we fighting a losing battle?
Long-term monitoring by the Australian Institute of Marine Science (AIMS) has identified COTs as a major driver of coral decline over recent decades. Their data is critical for early detection and intervention, but the challenge remains daunting. As Beeden warns, ‘If we don’t act fast, outbreaks can strip large areas of living coral, undermining the reef’s recovery.’
This outbreak isn’t just an environmental crisis—it’s a call to action. What do you think? Are we doing enough to protect the Great Barrier Reef, or is more radical action needed? Share your thoughts in the comments below.
