Scorching weather expects to cause widespread coral bleaching, says Reef Check

 By Olivia Miwil - May 8, 2023 @ 2:59pm

Corals spawn by releasing their gametes into the ocean and coral bleaching happens when corals lose their color. -Pic courtesy of Reef Check

KUALA LUMPUR: Reef Check Malaysia (RCM) is concerned that current unseasonal weather conditions might lead to widespread coral bleaching over the next few weeks.

RCM, scientists from University Malaya (UM) and University Malaysia Terengganu (UMT) are monitoring the mass coral spawning event that happens around this time of year.

Coral reefs in Tioman Island usually spawn around the full moon of April and October/ November. However, RCM's team has observed that corals at some of their monitoring sites did not spawn until yesterday, a month later than expected.

"The erratic weather we have been experiencing could have delayed the spawning this year. The worrying part, however, is that the water was 31 degrees Celcius last night.

"If it remains this hot, we are definitely going to be hit by bleaching this year," RCM senior programme manager Alvin Chelliah said in a statement.

Coral spawning describes the act of corals releasing gametes into the ocean, which then settle to form new coral colonies, and eventually new reefs.

When corals are stressed, they expel the algae (zooxanthellae) living in their tissues which leads to them losing their colour and exposing the white calcium carbonate skeleton underneath – hence the term "bleaching".

They not only lose their colour, they also lose their main source of nutrients, which comes from the zooxanthellae.

Mass coral bleaching events may result in the death of coral colonies and affect the wellbeing of marine life and industries that depend on healthy coral reefs.

RCM general manager Julian Hyde said coral reefs are extremely sensitive to the growing impacts of climate change.

"Marine life is not the only loser due to the loss of our coral reefs.

"Marine-based tourism could suffer and so will the local businesses and community in the area.

"No coral reefs means there will be no habitat, nursery, and food for fish. Fishermen will suffer and there are also implications for our food supply," he said,

The last mass coral bleaching event happened in 2010 when Malaysia's coral reefs suffered major damage, with an estimated 5 and 10 percent of corals dying.

Based on RCM's annual surveys, it took five years for the coral reefs to recover.