COTS in Raja Ampat

The reporting system outlined in this project is the official COTS monitoring and reporting system of the Marine Park, as endorsed by the Raja Ampat Marine Park Authority and local government for the management of COTS in the region. All culling events or sightings are required to be reported via this system.

It is only through collaborative evaluation and management that we can begin to collectively address the current challenges associated with Crown of Thorns Starfish outbreaks in Raja Ampat.

The Crown of Thorns Starfish

The crown-of-thorns starfish (Acanthaster planci) is a species native to coral reefs in the Indo-Pacific region. One of the largest starfish in the world, it grows up to 1m in diameter, and derives its name from its venomous thorn-like spines covering its upper surface. Crown of Thorns Starfish (COTs) are widely distributed across the Indo-Pacific. COTS feed on hard corals, by releasing the contents of their stomach onto the coral, and using digestive juices to dissolve the coral for consumption, leaving behind only the white skeleton. With few natural predators (including triton trumpet, pufferfish, porcupine fish and napoleon wrasse), a mature COTS can eat up to 1msq per week. On healthy coral reefs, where populations exist in balanced numbers, COTS play an important role in reef health; by predating on the fastest growing corals, they create space for the slower growing coral species and allow them to form larger colonies, contributing to greater coral diversity.

However in circumstances where COTS density increases to the point where the reef cannot recover fast enough from predation, this is considered an “outbreak”, which poses a significant threat to the overall health and resilience of a coral reef ecosystem. In extreme cases of outbreak, such as the Great Barrier Reef in Australia, large areas of reef have been affected: coral cover on surveyed reefs in the GBR declined 50% between 1985-2012, with COTS responsible for almost half of this decline (Australian Government, Great Barrier Reef Marine Park Authority).

At this point in time, the majority of reefs accessed within Dampier Strait and surrounding Raja Ampat, are healthy and abundant, with few COTS per hectare and coral growth and recovery in balance with any COTS predation. However, there are several known (and likely more unknown) locations where it is now considered that the densities and damage caused by COTS have reached outbreak levels, and these are areas of serious concern. At these sites preliminary observations show that as opposed to other parts of the world, COTS in Raja Ampat do not exclusively focus on fast growing corals, but rather predate upon any coral colony available on its path.

In a place like Raja Ampat, where both local livelihoods and a lucrative tourism economy depends exclusively on the health of coral reefs, it is vital to do whatever we can to mitigate further coral loss in the region. Rather than wait for existing outbreaks to potentially spread, or until significant damage occurs, The SEA People works closely with the Marine Park Authority, Conservation International, and other stakeholders and operators, in the ongoing monitoring and mitigation of the COTS outbreaks in the Dampier Strait region.

Management and Monitoring

The SEA People have implemented a system to record sightings, outbreak locations, and interventions in real time.  This real time information is accessible to the public in the form of an interactive map, populated by users in the field, and is used to better support a collaborative response and the implementation of more effective wide scale management.

The SEA People also provides training, equipment and capacity building to local community members and diving operations that enable them to play a significant role in COTS management efforts.  The participation and collaboration of this network of willing individuals and operators both improves detection of outbreaks, and increases the resources available to respond to these outbreaks.

Methods of COTS Removal

There are 2 methods of COTS removal.

1) Manual injection of the COTS carried out by trained divers or snorkelers. After consultation with marine scientists from Australia’s Great Barrier Reef Marine Park Authority, and reviews of existing research and literature relating to COTS outbreak mitigation, it has been established that a single injection of 20ml of household vinegar is highly effective in culling. With vinegar easily accessible, affordable and does not harm non target organisms, this is the preferred (and safest) method of COTS removal from a coral reef.
Contact us if you wish to receive training in this method of removal.

2) Manual removal of the COTS. This involves divers using equipment such as bamboo, wood, metal tongs etc, to manually remove COTS from the water. Whilst still effective, this is more labour intensive with less COTS being removed per hour then the injection method. This method also poses the risk of being stung by a poisonous spine, resulting in severe pain and swelling at the site of contact. Anyone removing COTS using this method should take appropriate precautions (gloves, equipment long enough to keep the COTS away from body).

Collaborating Partners

The organisations listed below play a crucial role in the current COTS management effort in Raja Ampat. Without this level of voluntary support the collection, construction and distribution of COTS Injecting Kits would not be possible.  It is through the determination, motivation and the kindness of the people behind these organisations that an effective management response can be achieved.

Trees to Seas

An NGO that connects people to the natural environment through participation in hands on conservation, Trees To Seas sources and funds essential parts needed for COTs injecting kits, and their delivery to Sorong, that otherwise cannot be sourced within Indonesia.  This level of support enables the provision of the most effective and safe equipment needed to conduct COTS culling events.  To donate to Trees to Seas and support their ability to continue supplying these kits, please click here.

EON Engineering

Established more than a decade ago, Emerald Ocean Nusantara (EON) has been operating in Papua Province providing a multitude of services including hydrotesting, dive equipment service and maintenance, and multiple community health and development projects such as freshwater systems for local villages, remote childhood health services, training and employment for local people. With environment and community at its core, EON purchases the remaining parts required for COTS injecting kits, and assembles and distributes the kits. Each kit requires manual assembly, which is conducted by volunteers at EON in collaboration with The SEA People.

Want To Help? You Can.


Record COTS Sightings

If you are in Raja Ampat, one of the most useful ways to contribute to the official management response; click or scan the QR code (at left) to record any evidence of COTS that you see on reefs.  No single individual or organisation can survey all the reefs in the region at anyone time, therefore by documenting your sightings in this simple 2 minute survey, you contribute directly to the official COTS Management plan in the region and conservation of the Marine Park.

Conduct a COTS Removal Event

If you are in the area and want to be more hands on, conduct a COTS Removal Event, and ensure you record your event survey listed above.  Collaborative management of COTS outbreaks in Raja Ampat is the only way to effectively address the issue.

Don’t act alone – please include your actions as part of the official management plan and contribute to the wider effort and greater understanding of COTS outbreaks in Raja Ampat.

If you need an injection kit, these can be obtained on arrival in Sorong, via our partner EON Engineering. Remember – diver and snorkel safety comes first, Contact Us if you wish to receive advice or training in COTS removal.

Donate an Injecting Kit, or Sponsor a Removal Event

Sourcing, assembling and delivering COTS kits takes considerable time and effort from a number of parties, many components of these kits must be delivered from overseas. The cost of one single kit amounts to $50USD per kit (parts only).  These kits only exist in Raja Ampat because of your donations.  Our Partner Trees to Seas currently collects donations and arranges assembly and delivery of kits.  Please DONATE the cost of a kit (or several!) and contribute to conservation efforts in Raja Ampat.

One of the most significant costs to running COTs management efforts is fuel – without fuel, the missions cannot go ahead. By making a donation you can directly support the purchase of fuel used in COTs mitigation efforts. Make a Donation

Sponsor a COTS Training Session

In order to develop and increase the participation of local stakeholders in a collaborative management response, training sessions are necessary in order to raise awareness about the COTS issue in Raja Ampat, provide an understanding of safety and good technical practice during removal, and gear maintenance.  Training sessions includes: half day theory, one practical session and delivery of 2 COTS injection kits. Make a Donation


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