Crown of Thorns Starfish 

A stakeholder approach to Management

Report your COTS sightings or culling events by scanning or clicking the QR code

Click Here for an interactive map of known COTS Outbreaks in Raja Ampat 

 Raja Ampat Marine Park Authority aims to work collaboratively with a variety of local stakeholders to address the Crown of Thorns Starfish situation with monitoring and controlled culling. 

Crown of Thorns Starfish is a species native to coral reefs in the Indo-Pacific region.  One of the largest starfish in the world, it can grow up to 1m in diameter.
Widely distributed throughout the Indo-Pacific, these starfish, covered with venomous spines, are also present in Raja Ampat.  COTS feed on hard corals, and with few natural predators (triton trumpet, pufferfish, porcupine fish and napoleon wrasse), a mature COTs can eat up to 1msq per week.   COTs mature quickly, and first breed when they are 2-3 years old, with each female producing up to 60 million eggs during a single spawning season. On healthy coral reefs, where the ecosystem is in balance,  COTS play an important role in that balance; by predating on the faster growing corals they create space for the slower growing corals and allow them to form larger colonies, and in doing so contribute to coral reef diversity and health.

However, when ecosystems become unbalanced and the density of COTS increases to the point where the reefs cannot recover from the level of predation, this is considered an ‘outbreak’, which then poses significant risk to the overall health of the coral reef.

Whilst many of the reefs in Raja Ampat are healthy, there are unfortunately known locations where by COTS are considered to be at outbreak level, and these areas are of serious concern.   Typically scientists link outbreaks of the COTS starfish to spikes in ocean nutrients caused by coastal and agricultural run-off, including waste water run-off.  However, in some instances, for example remote outer reefs, causes for outbreaks are unknown.  In Raja Ampat, the causes behind outbreaks are currently unclear.

Given the impact of climate change and the ever escalating threats that are contributing to deterioration of coral reefs worldwide, it is essential that Raja Ampat, one of the last remaining locations on the planet where coral thrives, is protected from additional harm from Crown of Thorns starfish. 


Why Collaboration is essential for Success:

Raja Ampat Marine Park is comprised of over 2 million hectares of island archipelago and complex coral reef systems.

There is currently no single organisation that can effectively monitor COTs populations and densities over such a large scale, so it is the hope of the Raja Ampat Marine Park Authority that all stakeholders within the area, including resorts, homestays, liveaboards, local communities, NGOs and local government, all participate in a collaborative approach to COTS control and management.

Given that all livelihoods in Raja Ampat depend upon a continued state of reef health, it is essential that all stakeholders recognise it is a collective responsibility to contribute to the management of COTS in the region.  

We encourage all stakeholders to participate in the Marine Park Authorities official COTS Control and Management by actively and regularly conducting COTS control (culling and/or removal from water) and recording this information in the OFFICIAL REPORT. 

If you are diving or snorkelling in the region and see COTS, we actively encourage you to record your sightings in the OFFICIAL REPORT.

Through collaboration, we have the greatest chance for success; It is only through a collaborative stakeholder approach that we can deliver an effective management response to a potentially disastrous outcome for the reefs of Raja Ampat, and the communities who rely upon them.

Raja Ampat Marine Park Authority conducting COTS removal in the Dampier Strait

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