Crown of Thorns (COTS) Population Size Estimation

The objective of this project is to estimate the total number of adult crown-of-thorns starfish (COTS) on reefs between izard Island just south of the northern boundary and Cape Grafton just north of the southern boundary (between 14o30’S and 17o00’S). This narrow section of the northern shelf has hydrodynamic and water column productivity properties conducive to the simultaneous eruption of multiple primary outbreaks of COTS, with the trigger being major flood plumes during the Wet Season. These outbreak populations then spawn a decadal cascade of secondary outbreaks downstream with major impacts on the coral cover of reefs throughout the central Great Barrier Reef. The purpose of estimating the number of adult starfish of spawning size in 2013 is to determine the size of the potential control target for an industry-led programme of culling that has been funded by the Australian Government.