Crown-of-thorns starfish management

COTS diver locating crown-of-thorns starfish

Why we manage COTS in the Great Barrier Reef Marine Park

Why do we manage crown-of-thorns starfish in the Marine Park?

Crown-of-thorns starfish outbreaks cause significant damage to coral reefs across large spatial scales, and are one of the major causes of coral decline across the Great Barrier Reef over the past 40 years. The damage from crown-of-thorns starfish outbreaks adds to the damage from other major causes of coral decline — tropical cyclones and coral bleaching events. Out of these three major causes of coral decline, crown-of-thorns starfish outbreaks are the only one that can be mitigated through direct local management.

The Outlook Report identifies crown-of-thorns starfish outbreaks as a significant threat to the long-term health of the Great Barrier Reef ecosystem. The Reef 2050 Long-Term Sustainability Plan and the Great Barrier Reef Blueprint for Resilience outline key management actions that should be taken to reduce threats to the Reef, including management of crown-of-thorns starfish outbreaks.

Minimising the impact of crown-of-thorns starfish outbreaks is considered one of the most scalable and feasible direct management interventions available today to enhance the Great Barrier Reef’s long-term health and resilience in the face of climate change.

By taking direct action to protect coral, crown-of-thorns starfish management complements other initiatives that are under development in the Reef Restoration and Adaptation Program, thus supporting the Great Barrier Reef’s capacity to resist, repair and recover from the impacts of a changing climate.

For more information about crown-of-thorns starfish outbreaks see our FAQ’ s

How do we manage crown-of-thorns starfish in the Marine Park?

Since the 1980s, the Great Barrier Reef Marine Park Authority (the Marine Park Authority) has worked in partnership with research institutions, government agencies, and the tourism industry to understand the dynamics and causes of crown-of-thorns starfish outbreaks and implement management responses.

The Marine Park Authority’s Crown-of-thorns Starfish Strategic Management Framework outlines the strategic approach to achieve the crown-of-thorns starfish management targets from the Reef 2050 Long-Term Sustainability Plan and the Great Barrier Reef Blueprint for Resilience.

This strategic and adaptive crown-of-thorns starfish management framework includes:

  • preventative actions to address factors that may contribute to the initiation and spread of outbreaks
  • tactical actions by the Crown-of-thorns Starfish Control Program to reduce the damage caused by outbreaks when they occur
  • monitoring to provide an early warning of developing outbreaks and guide tactical action
  • research priorities that are most critical to improving crown-of-thorns starfish management.

Our Crown-of-thorns Starfish Strategic Management Framework provides the guiding principles to actively manage crown-of-thorns starfish now, while also promoting and supporting research and innovation to improve crown-of-thorns starfish management into the future.

It recognises that effectively addressing the crown-of-thorns starfish threat requires coordination across state and federal government agencies, research institutions, Reef-based industries, and community action groups. The Crown-of-thorns Starfish Strategic Management Framework seeks to inform, empower and guide these groups to deliver a coordinated approach to crown-of-thorns starfish management in the Great Barrier Reef Marine Park.

Although the Crown-of-thorns Starfish Strategic Management Framework is focused on the Great Barrier Reef Marine Park, the general management principles can be applied in other coral reef areas where crown-of-thorns starfish outbreaks occur, both nationally (for example, the Torres Strait) and internationally.

How can you help us manage crown-of-thorns starfish in the Marine Park?

All users of the Great Barrier Reef Marine Park, including community members and industry stakeholders, are encouraged to engage in crown-of-thorns starfish management. There are two primary ways you can help:

  1. Report crown-of-thorns starfish sightings to the Marine Park Authority using the Eye on the Reef Sightings app. This crown-of-thorns starfish sightings information may then be used to guide more in-depth assessments by reef managers, marine parks rangers and/or Crown-of-thorns Starfish Control Program vessel crews.
  2. Protect your patch by culling crown-of-thorns starfish in your local area. If you choose to do this, please consult the Marine Park Authority’s Crown-of-thorns Starfish Control Guidelines. These guidelines provide important information on how to conduct this activity safely and effectively. Permits are required to conduct culling in some Marine Park Zones. Check requirements here . If required, crown-of-thorns starfish control permit applications have no assessment fee and can be submitted through the Permits Online application portal.

A few important health and safety tips for those interested in culling crown-of-thorns starfish to protect their local patch:

  • Crown-of-thorns starfish have hundreds of long needle-like venomous spines covering their bodies and arms, presenting a health and safety risk to people who interact with them
  • Reaction to a crown-of-thorns starfish spike can vary considerably among people, ranging from localised pain and swelling at the puncture site to severe anaphylactic shock
  • People undertaking crown-of-thorns starfish culling activities need to take suitable precautions to avoid being spiked (for example, wear personal protective equipment) and should also be confident in the appropriate first aid treatment before doing the activity.

A few important tips to ensure that your crown-of-thorns starfish culling efforts are effective:

  • The recommended method for crown-of-thorns starfish culling involves injecting starfish at the base of an arm with approved solutions (for example, bile salts or household vinegar)
  • If the dosage and injection technique are delivered correctly, these solutions can be highly effective at killing crown-of-thorns starfish in under 48 hours
  • Culling through lethal injection is safer than collection and burial onshore because it does not require handling this venomous starfish
  • Do not attempt to kill crown-of-thorns starfish by cutting them into pieces, because pieces of a single starfish can regenerate into multiple starfish and make the problem worse
  • It takes some skill and practice to cull effectively using the injection technique, please refer to the Crown-of-thorns Starfish Control Guidelines for more tips.

Resources and publications on crown-of-thorns starfish management

Media and videos on crown-of-thorns starfish management

Mighty Triton sea snail a natural predator for crown of thorns starfish

All hail the mighty triton shell

Under siege crown-of-thorns starfish meet their match

Under siege crown-of-thorns starfish meet their match

Protecting coral on the great barrier reef

Protecting coral on the great barrier reef