Mass coral bleaching expected in Mar-May 2027

Mass coral bleaching is likely in Singapore in Mar-May 2027. NParks will be monitoring.

Mass coral bleaching at Kusu Island, Jun 2024

Karenne Tun, group director of NParks’ National Biodiversity Centre said that while recent studies show that repeated bleaching in Singapore has caused relatively low immediate coral death – usually under 10%, and about 5% in the 2024 bleaching event – the reefs are changing and have “flattened” over time. Repeated bleaching and shifts to simpler reefs may affect coral spawning, limiting the  reefs’ long-term resilience even if they appear to recover.

Marine biologist Huang Danwei, deputy head of NUS’ Lee Kong Chian Natural History Museum noted that increased frequency of coral bleaching events means reefs have less time to recover between them. When corals do not recover, the flora and fauna that depend on reef habitats also decline in abundance and diversity.

According to third World Ocean Assessment: “The reefs of today will not be the reefs of tomorrow, and shifting baselines need to be considered when setting objectives, with respect to conservation, restoration and regeneration".

Current efforts include NParks’ 100k Corals Initiative, launched in December 2024 to plant 100,000 corals in Singapore over the next decade and beyond. It is the most extensive coral restoration effort in Singapore to date. Jani Tanzil, facility director of the St John’s Island National Marine Laboratory, noted that in Singapore’s case, where only about 10 sq km of reefs remain, there is no choice but to turn to this last resort of reef restoration to combat their decline.

Coral spawning muted in 2025 after mass coral bleaching in 2024

Once a year, on the fourth month, around four days after the fourth full moon of the year, our corals release eggs and sperm all at the same time! Called mass coral spawning, this year's event was 'muted', most likely because of mass coral bleaching in 2024. Scientists say the scale of the event was similar to the spawning in 2017, which occurred months after the 2016 mass bleaching event. 

However, Dr Karenne Tun, group director of NParks’ National Biodiversity Centre noted that while spawning was muted in 2017, it improved significantly in 2018 and 2019. “Thus, we are hopeful that the corals will recover to full fecundity within the next two years if our reefs are not subjected to any further thermal or other stressors,” she added.

More about mass coral spawning and this blog post on the 2024 event