Waging a new war on crown-of-thorns starfish
Reef health
A program to control crown-of-thorns starfish outbreaks on the northern Great Barrier Reef between Lizard Island and Cairns is being stepped up this month as the pest species continues to attack reefs across the entire Marine Park.
The northern region of the Reef is known to scientists as a breeding ground for the invasive starfish - the area is often referred to as the “initiation box”.
Four major outbreaks of COTS have been detected in the past 40 years, which generally begin in the northern region and spread south across time.
The latest Great Barrier Reef Marine Park Authority health report states the area between Cairns and Lizard Island is now one of two sections where the “most severe outbreaks remain” from the last major starfish infestation in the early 2010s.
“Since December, surveillance and control activities have been carried out on 128 reefs,” the report states.
“Around one-third of these reefs now have COTS at levels that allow coral to recover, while active control is underway on about half of the reefs to reduce impacts.”
GBRMPA chief scientist Roger Beeden said the program was focused on controlling the recent outbreaks through a targeted approach.
“Through systematic culling, with the right capacity, we can reduce the impact of these coral predators,” he said.
In 2024/25, the GBRMA culled close to 74,000 COTS across about 11,700ha of reef habitat, with 234 specific reefs targeted.
The Federal Government-funded $25m-a-year program uses six boats that concentrate on about 500 of the more-than 3000 reefs across the entire marine park.
Divers individually inject agents such as cow bile into the coral-eating starfish, with the region between Irene Reef and Lizard Island a particular recent focus.
