Crown of Thorns Starfish (COTS) Project
COTS is an invasive starfish that feeds primarily on stony corals and can consume up to ten square meters every year. Crown of Thorns are one of the largest starfish in the world and can reach up to 35cm! They usually feed at night but you can see evidence of their presence in the white ‘scars’ they leave on the corals they consume. Natural predators of the Crown of Thorns include the triton trumpet snail, humphead wrasse, and triggerfish; some of these have now become extremely rare, leaving the COTS with limited natural population control.
An eradication project can take a number of years to have an impact upon a COTS population and removal trips need to be done on a regular basis for best results. Once the population is under control, it can take many more years for a badly damaged reef to recover.
Our COTS eradication project has been running now since 2007 and we are seeing a definite reduction in the number of starfish found on our coral reefs around the island. Eradication is conducted a minimum of twice a month, or more if necessary. In 2018 we imported injectors from Australia which administer vinegar whilst in the water. This is now recognised by many, including the Great Barrier Reef Marine Park Authority as one of the fastest and most environmentally friendly ways of controlling populations.
This is a long term ongoing strategy in order to yield successful results and part of our ongoing commitment to enhancing and protecting our marine environment. We submit our data to a regional monitoring program to enable populations analysis and inform management plans to address potential outbreaks. We encourage you to report sightings of COTS on our house reef, but ask you to please take care not to touch them!