Crown of Thorns Starfish Control Program

Scope of Work

PMG has held a contract with GBRMPA for over 5 years to control the Crown of Thorns Starfish (COTS), which is a severe threat to the Great Barrier Reef.

The Crown of Thorns Starfish (COTS) is considered a threat primarily due to its significant impact on coral reef ecosystems, particularly the Great Barrier Reef. Key reasons why COTS is seen as a threat are:

1. Predation on Coral: COTS feeds on coral polyps by extruding its stomach over the coral and releasing digestive enzymes. This feeding behaviour can lead to extensive damage to coral reefs over time, especially during outbreaks when population numbers are high.
2. Population Outbreaks: COTS populations can undergo outbreaks, where large numbers of starfish congregate and feed on coral. These outbreaks can result in rapid and widespread coral mortality, leading to declines in coral cover and overall reef health.
3. Impact on Biodiversity: Coral reefs are highly diverse ecosystems that support numerous species of fish and other marine life. Damage to coral reefs by COTS can disrupt these ecosystems and reduce biodiversity.
4. Reef Resilience: Healthy coral reefs are crucial for the resilience of coastal communities and economies that depend on them for fisheries, tourism, and coastal protection. COTS outbreaks threaten the ability of reefs to recover from other stressors such as climate change and pollution.
5. Challenges in Control: Controlling COTS outbreaks can be challenging and resource-intensive. Effective methods such as culling and monitoring require dedicated efforts and resources, often involving coordinated programs by organizations like GBRMPA (Great Barrier Reef Marine Park Authority).

Trips aboard our vessel, PMG Odyssey, last around 10 days. We operate two 5m rigid inflatable vessels designed to be easily lifted onto the Odyssey for transit.

During each trip, 12 divers conduct up to 4 dives daily, each lasting a maximum of 50 minutes at depths of up to 20m. The crew stays at sea, visiting various locations across the Great Barrier Reef, primarily in the Townsville and Whitsunday regions.

Typical activities during these trips include:

• Manta towing to assess COTS numbers and coral cover, aiding in prioritizing efforts.
• Reef Health Impact Surveys.
• Research activities such as triton collection, plankton tows, tissue sampling, and regular COTS collection for AIMS.
• COTS culling which involves injecting COTS with vinegar.

GBRMPA considers the program highly successful, noting significant improvements in COTS management across reefs managed by PMG, transitioning from 'Severe Outbreak' to 'Potential' and 'No Outbreak' statuses.