Outbreak status is assigned to all actioned reefs. It is calculated as the average number of COTS recorded across all manta tow surveys conducted at each reef and is expressed as COTS/tow (2,000 m2 survey area).

• No COTS Detected – Manta tow surveys recorded no COTS or COTS feeding scars.
• No Outbreak – Manta tow surveys recorded 0 - <0.11 COTS/tow.
• Potential Outbreak – Manta tow surveys recorded 0.11 - <0.22 COTS/tow.
• Established Outbreak – Manta tow surveys recorded 0.22 - <1 COTS/tow.
• Severe Outbreak – Manta tow surveys recorded >=1 COTS/tow.

COTS often aggregate for both feeding and spawning and this can result in large variability in starfish density among replicate manta tow surveys at each reef.

Although average COTS numbers are low on ‘No Outbreak’ reefs, there may be specific sites on these reefs where starfish numbers are above sustainable levels and targeted culling is required to protect coral.

• ‘Catch per unit effort (CPUE)’ is the total number of COTS culled divided by the number of diver minutes spent searching for and culling starfish. CPUE is categorised as follows:
• 0.00 - <0.02 COTS/min: COTS density is below the level at which coral growth can outpace coral loss from starfish predation. COTS spawning success may be suppressed.
• 0.02 - <0.04 COTS/min: COTS density is low enough to sustain coral growth on reefs with < 40% live coral cover.
• 0.04 - <0.08 COTS/min: COTS density is low enough to sustain coral growth on reefs with > 40% live coral cover.
• 0.08 - <0.2 COTS/min: COTS density is too high and coral loss from starfish predation will outpace coral growth.
• >=0.2 COTS/min: COTS density is well above sustainable densities and rapid coral loss from starfish predation will occur (coral loss to below 5% live cover is expected within 12 months). 
   

• 'Percentage categories of live coral cover’ are average hard coral cover estimates generated from manta tow surveys at each actioned reef. Tracking changes in coral cover status through time provides an indication of the coral protection outcomes achieved by the COTS Control Program and helps to quantify other cumulative impacts on reef health.
• Estimates from Reef Health Impact Surveys (RHIS) are also provided in the summary statistics panel. COTS Control Program RHIS are predominantly conducted in shallow reef slope and crest habitats. They typically generate higher estimates of coral cover than manta tow surveys.

• During 2024-25, the Crown-of-thorns Starfish Control Program:
• Actioned 232 target reefs for surveillance and COTS culling where required
• Conducted 18,282 manta tow surveys and 3,457 Reef Health and Impact Surveys (RHIS)
• Culled 73,881 COTS across 11,710 hectares of reef habitat
• Spent 18,008 hours underwater culling

This dashboard is best viewed on a desktop. Tap here for a mobile-friendly version.

• About the 2024-25 Report Dashboard:
• This 2024-25 report includes reefs actioned for surveillance and culling by the COTS Control Program and the Reef Joint Field Management Program (RJFMP). The COTS Control Program integrates Great Barrier Reef monitoring data and intelligence from the Australian Institute of Marine Science (AIMS) Long-Term Monitoring Program (LTMP) to inform strategic planning and operational decisions. AIMS LTMP reports and data can be accessed via the Reef Reports Hub.
• Summary data presented in this report extends from 2012 to June 30th 2025. 
   

• During 2023-24, the Crown-of-thorns Starfish Control Program:
• Actioned 192 target reefs for surveillance and COTS culling where required
• Conducted 30,596 manta tow surveys and 3,524 Reef Health and Impact Surveys (RHIS)
• Culled 50,227 COTS across 11,640 hectares of reef habitat
• Spent 16,657 hours underwater culling

Interactivity: Users can toggle the display to view key performance indicator metrics (panel 1), crown-of-thorns outbreak status (panel 2), live coral cover (panel 3) and culling activity (panel 4). Additionally, selecting a management area from the inset map will filter the display, and finer-scale information is revealed by hovering over a reef of interest. See the descriptions below for details on the calculation of each displayed metric.

2022-23 Annual report 

• During 2022-23, the Crown-of-thorns Starfish Control Program:
• Actioned 201 target reefs
• Protected 13,740 hectares of reef habitat through targeted culling
• Culled 48,225 COTS
• Spent 21,928 hours underwater

The dashboard below displays key performance indicators and the location and summary information for reefs that were managed by the Crown-of-thorns starfish Control Program during the 2021-22 financial year.

Users can click the ‘select the map view’ buttons to view crown-of-thorns starfish outbreak status, live coral cover and culling activity metrics.

Selecting a management area from the inset map (bottom left corner) will filter the map display and summary statistics to a geographic region.

More detailed (reef-scale) information is revealed by hovering the cursor over a reef of interest.