Optimising crown-of-thorns starfish control effort on the Great Barrier Reef

Area of Science:

• Marine biology
• Ecology
• Conservation science

Background:

• Crown-of-thorns starfish (COTS) outbreaks cause significant coral loss on the Great Barrier Reef (GBR).
• Climate change exacerbates disturbances like cyclones and coral bleaching, increasing the need for effective COTS management.
• Manual culling is a primary method for controlling COTS populations.

Purpose of the Study:

• To evaluate the impact of spatial control strategies for COTS on coral cover.
• To determine optimal COTS culling strategies considering larval dispersal and connectivity.

Main Methods:

• A metapopulation model was developed, integrating predator-prey dynamics, larval dispersal, and starfish removal.
• Simulations compared different spatial control strategies for COTS outbreaks.

Main Results:

• Targeting COTS outbreaks at their source, particularly between Cairns and Cooktown, is the most effective strategy.
• Expanding control efforts spatially protects a larger area but reduces overall coral cover on the GBR.
• Spatial control strategies significantly influence the effectiveness of COTS management.

Conclusions:

• Strategic spatial targeting of COTS control, informed by larval connectivity, enhances management efficiency.
• Optimized COTS management is vital for GBR resilience amid escalating climate change pressures.
• Efficient reef management practices are crucial for the long-term health of the Great Barrier Reef.