Overview:
Marine scientists have confirmed a crown-of-thorns starfish outbreak in Koror's Ngederrak Conservation Area, prompting calls from officials and reef experts for urgent monitoring and community action to protect one of Palau's most vital coral ecosystems.
By: Laurel Marewibuel
Koror, Palau — Marine scientists have identified an outbreak of crown-of-thorns starfish in Koror’s Ngederrak Conservation Area, raising concerns among local officials and community members about potential damage to the state’s coral reefs.
Professor Peter Mumby of The University of Queensland, who has been monitoring reefs in Ngederrak for several years, delivered the assessment at a recent presentation hosted by the Palau International Coral Reef Center. Mumby warned that while the crown-of-thorns starfish, or COTS, is a native predator, its populations can expand rapidly and inflict severe coral loss if left unchecked.
“Because these starfish are often hidden during daylight hours, they’re difficult to monitor, which makes early detection essential,” Mumby said. His update included management strategies used in Australia to control outbreaks that could be adapted for Palau if needed.
The briefing drew representatives from Koror State Government and the Ministry of Agriculture, Fisheries and the Environment, signaling coordinated interest from both state and national agencies. Local participation at the session underscored the wider civic stake in protecting reef resources.
“Coral reefs are one of Palau’s greatest natural resources,” said a Palauan resident in his 40s who attended the presentation. “They support our fisheries, protect our coastlines, attract visitors, and are deeply connected to our culture and way of life. While the crown-of-thorns starfish is a natural part of the reef ecosystem, outbreaks can quickly damage healthy coral if left unmanaged. That’s why early detection and monitoring are so important. Protecting our reefs is a shared responsibility, and by working together — government agencies, scientists, and local communities — we can help ensure these ecosystems remain healthy for future generations.”
Concerns about reef health are widely shared. “As a Palauan, it worries me to hear about anything that threatens our coral reefs,” said Maria, who works in the private sector. “They’re one of our greatest treasures, and I hope everyone — from the government to local communities — works together to keep them healthy.”
COTS feed on live coral and can reduce reef complexity and fisheries habitat when outbreaks persist. Loss of coral can also weaken natural coastal defenses and diminish tourism value, with potential long-term economic and cultural consequences for Palau.
Experts say prompt, coordinated action can limit damage. Recommended measures include:
• Intensified monitoring to detect and map COTS aggregations, especially at night when the animals are more active.
• Targeted removal programs, using trained divers and proven control methods.
• Public reporting systems that enable fishers, tour operators and residents to report sightings quickly.
• Community engagement and education to expand local capacity for detection and response.
• Long-term reef resilience measures such as reducing land-based pollution and managing fishing pressure to support healthy fish populations that can naturally help control COTS larvae and juveniles.
Palauan authorities and conservation groups face a narrow window to act before coral loss accelerates, officials said. The involvement of state and national agencies, combined with scientific input from visiting experts, provides a framework for intervention, but community participation will be crucial.
“Early detection and coordinated response are essential,” Mumby said. “With the right tools and community involvement, outbreaks can be managed before they cause irreversible damage.”
The Palau International Coral Reef Center thanked Mumby for sharing his findings and said it will continue working with Koror State and the national government to assess next steps. Officials urged residents and visitors to report any COTS sightings to local conservation authorities and to support reef-friendly practices.