Climate change skews sea turtle conservation in Malaysia

REDANG: On a secluded beach on the east Malaysian island of Redang, a group of volunteers carefully dig into the sand. Their mission: moving newly-laid turtle sea eggs to a shadier, tree-lined location on the beach in a bid to ensure the eggs are incubated and hatched in cooler conditions. 

The move is part of efforts by conservationists in Malaysia to ensure a more balanced sex ratio among sea turtle hatchlings, which is heavily influenced by temperatures during incubation. 

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Researchers and wildlife activists fear rising sea and surface temperatures due to climate change could jeopardise efforts to protect already endangered sea turtles in Malaysia, with observers at the Chagar Hutang Turtle Sanctuary on Redang already seeing fewer males being hatched in recent years. 

“Anywhere over 30 degrees Celsius of average incubation temperature is gonna push you into a 100 per cent female-biased hatching production, and anywhere closer to 28 (degrees Celsius) and under, you’re going to have the opposite effect of male bias,” said Nicholas Tolen, a researcher and PhD student at University of Malaysia, Terengganu (UMT).

Scientists at the Chagar Hutang Turtle Sanctuary on Redang island, Malaysia are now trying to keep the sea turtle eggs cool and safe by transferring new nests to shadier areas. According to Tolen, this will have a positive influence on a more equal ratio of sexes for the hatchlings. Now, the sanctuary is getting help from volunteers to carefully move the nests several metres from the shore to a shady strip surrounded by markers, closer to the island’s rainforest.

According to UMT researcher Mohd Uzair Rusli, it’s better to incubate the eggs out in the open under the shade of trees, as an artificial incubator might disrupt the sea turtle hatchlings’ understanding of the earth’s magnetic field, thus causing them to lose direction—and their ability to nest.

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Conservationists at UMT, which runs the Chagar Hutang Turtle Sanctuary, began relocating turtle nests for years to provide what they believed was a safe haven for the hatching of turtle nests. At first, the scientists discovered that the hot sand of the beach was helping facilitate a faster and higher birth rate of the hatchlings—but it soon became apparent that the relocated nests, which were baking under the hot sun, resulted in feminising most of the offspring. Based on research conducted by Tolen, the Sanctuary began to relocate nests that were at risk to shadier portions of the beach.

Although the success of the current program is still being measured, it appears that temperatures across Malaysia, like the recent heatwaves, are only bound to increase, according to Chung Jing Xiang, a senior lecturer in science and marine environment at UMT. According to Chung, increasingly hotter heatwaves are now being prolonged and are more widespread across Malaysia due to the lasting effects of El Niño.

“Instead of bringing moisture to our region, it took away our moisture and bring it to the Pacific Ocean. So when we have this moisture reduced, rain will be less likely to form and we will have fewer clouds in our sky. So this will cause us to have a hotter and drier weather,” Chung told Reuters.

According to Chung’s research, at the current rate, the sea surface temperature over Malaysia has been showing an increasing trend of about 0.2 degrees Celsius per decade since 1980. Analysts said the average surface temperature of the South China Sea surrounding Redang has been climbing steadily towards 30 degrees Celsius in recent decades, and could eventually exceed the ideal incubation temperature range of between 28 and 30 degrees Celsius for ensuring a balanced sex ratio. 

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After hatching, the researchers transfer the hatchlings to a small nursery before releasing them at night to reduce their exposure to predators.

For decades, the population of marine turtles has been in serious decline across Malaysia, often due to the harvesting of their eggs, overfishing, and lack of enforcement of conversationalist policies. Leatherbacks used to be a star attraction for visitors to Malaysia’s northern state of Terengganu, with tens of thousands of female turtles nesting on beaches there each year until the population collapsed in the late 80s.