80 per cent of Malaysian corals bleached due to heatwave

SHAH ALAM - The devastating effects of coral bleaching are being felt across Malaysia, with temperatures reaching unprecedented levels since records began in the early 1980s.

Coralku Conservation, a non-profit dedicated to coral reef health, has highlighted that this year's bleaching event and heatwave are the most severe to date, with bleaching still ongoing.

“We are predicting mortality due to bleaching between 40-60 per cent, and this will result in long-lasting damage to the coral reef ecosystem and economy.

“The situation is less severe in the southern part of Peninsular Malaysia around Johor state and Pulau Tioman,” they said when contacted recently.

According to Coralku Conservation, less than 10 per cent of corals were bleached in 2023, while around 25 per cent were affected in 2020, with moderate bleaching observed at sites like Pulau Perhentian and Tioman. In 2019, 55 per cent of corals were bleached, marking a significant event. This year, bleaching has been most severe in Terengganu, with less impact in Tioman and Johor.

The research-driven coral restoration and conservation non-profit enterprise added that major bleaching events previously recorded in Malaysia occurred in 1998 and 2010, which marked the first and second global coral bleaching events.

This year, coral bleaching began in early May and continues, with no significant recovery observed and no expectation of full recovery within the year.

Coralku Conservation also pointed out that tropical hard coral bleaching refers to the whitening of the coral's skeleton, which occurs when the symbiotic relationship between the coral polyp and its algae, known as zooxanthellae (or Zoox), breaks down.

“During this breakdown, the coral expels all its algae partners, causing the coral to turn white.

"The coral hosts millions of these microscopic algae, which, like all plants, produce energy through photosynthesis.

"These energy products are passed on to the coral.

"Depending on the coral species, the algae symbionts provide up to 90 per cent of the coral's energy requirements through photosynthesis.

"A bleached coral is under significant stress because it is essentially starving," they added.

When corals bleach, they are effectively starving and under severe stress, impacting their ability to reproduce and grow due to the lack of energy needed for spawning and development.

Coralku Conservation stated that the 2024 bleaching event will have severe and enduring effects on coral ecosystems.

Meanwhile, Reef Check Malaysia marine biologist and programme coordinator, Alvin Chelliah said Malaysia is currently experiencing what is considered the fourth global bleaching event.

According to their surveys, some reefs have up to 80 per cent bleaching. While there has been some recovery in recent weeks, it is still too early to determine the extent of recovery or mortality.

“You can't prevent coral bleaching, but you can prevent pollution, physical damage, unsustainable use of the reef, and overfishing.

"By addressing these issues, you will help coral become more resilient to bleaching,” Alvin told Sinar Daily when contacted.

Alvin stressed that locally managed marine protected areas are crucial for mitigating local threats and enhancing reef resilience to climate change.

Reef Check Malaysia has established community programmes in Tioman, Redang, Mersing, Mantanani, and islands off Semporna, such as Selakan, Larapan, and Mabul.

He highlighted that these local Community Marine Conservation Groups are vital in managing local impacts such as marine debris, coral predators, physical damage, and ghost nets.

They also play a key role in monitoring reef health and rehabilitating damaged reefs.