Crown of Thorns Starfish Outbreak in American Samoa

By AIC guest blogger, Kristine Bucchianeri, Coral Reef Advisory Group, American Samoa

Crown of Thorns Starfish eating coral at Taema Banks of Tutuila Island. Credit: National Parks Service

Crown of Thorns Starfish eating coral at Taema Banks of Tutuila Island. Credit: National Parks Service

American Samoa is currently experiencing a Crown of Thorns Starfish (COTS; alamea, Acanthaster planci) outbreak on their coral reefs. COTS are a type of starfish that prey upon coral tissue and can cause significant damage to reefs.  While normally rare, COTS occasionally have huge population spikes where millions of individuals suddenly appear on the reefs.

The last COTS outbreak in American Samoa was in 1977 and despite the removal of 480,000 starfish, many more remained on the reef. Consequently, over 80% of the Territory’s corals were estimated to have been killed.

National Parks diver, Bert Fuiava, uses Sodium Bisulphate to kill a COTS. Credit: National Parks Service

National Parks diver, Bert Fuiava, uses Sodium Bisulphate to kill a COTS. Credit: National Parks Service

In response to the alarming number of COTS around Tutuila, the main island in American Samoa, a team of agencies have activated the Assessment and Rapid Reef Response (ARRR) Plan to survey and remove the COTS. By keeping track of the spreading population of COTS, response can be more effective and priority areas are kept protected. Agencies are also conducting outreach events in communities and schools and holding trainings with local fishermen to safely assist with removal efforts.

Despite these efforts, more assistance will be needed over the next few years. Continued funding and qualified divers will be essential to supporting local efforts.

To learn more about this COTS outbreak, please contact Kristine at Kristine.bucchianeri@doc.as. Also, visit the AIC web page on American Samoa to learn more about their other coral reef-related activities.

Map of COTS densities and  numbers collected in American Samoa. Credit: Alice Lawrence, Department of Marine and Wildlife Resources

Map of COTS densities and numbers collected in American Samoa. Credit: Alice Lawrence, Department of Marine and Wildlife Resources

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