Sabah coral reefs under threat from rising crown-of-thorns starfish population

 SEMPORNA: The population of crown-of-thorns (COT) starfish in east coast Sabah reefs has risen sharply, posing a serious threat to coral ecosystems.

According to Reef Check Malaysia's Annual Reef Health Survey, COT starfish numbers have exceeded the ecological threshold that a healthy coral ecosystem can sustain since 2022.

"Natural COT startfish populations should remain at approximately 0.2 to 0.3 individuals per 100 square metres, yet surveys across multiple east coast sites have recorded numbers far beyond this limit.

"Left unmanaged, COT starfish outbreaks can rapidly consume large areas of living coral tissue, exacerbating existing pressures from bleaching, sedimentation and destructive fishing.

"These escalating numbers highlight the urgency for immediate action to prevent further coral loss," the statement said.

Throughout the year, the non-governmental organisation and its partners have been repeatedly mobilised in response to outbreak hotspots from Lahad Datu to Semporna.

Early figures indicate that this year alone, 7,624 COT starfish have been removed through coordinated field operations.

The latest three-day joint operation between Reef Check, Buwan Dive Resort, Yayasan Sabah and Community Marine Conservation Groups (CMCGs) in Adal–Bakungan and the Silam coast, which removed over 2,000 COT starfish, adds momentum to ongoing regional mitigation efforts aimed at protecting coral ecosystems already under stress.

Reef Check Malaysia's Programme Manager for South Sabah, Adzmin Fatta, said that while removal operations help ease immediate pressure on coral reefs, deeper scientific research is needed to understand the local factors driving these outbreaks.

"As coral reefs along Sabah's east coast face mounting challenges from climate change, sedimentation, coastal development and nutrient runoff - conditions that may favour COT starfish outbreaks - proactive intervention remains essential.

"Reef Check Malaysia and its partners will continue strengthening monitoring, rapid response and community-led conservation efforts to ensure that reef ecosystems, and the communities that depend on them, remain resilient and protected for generations to come."