Malaysian sea turtles endangered as male hatchlings experience heat

Redang Island, Malaysia Under a full moon, a ball-shaped creature emerged from the South China Sea onto the quiet beach of Redang Island in Malaysia.

Under the watchful eye of a team of volunteers, green sea turtles slowly move along the fine white sand to the top of the beach, digging into the sand with their flippers before laying their precious eggs.

Observers from the Chagar Hutang Turtle Sanctuary in the northeastern state of Terengganu sneak in to record the number of turtle eggs and measure the turtles nesting in the sand.

Redang Island is famous for its turtles. “We want to protect the treasures here,” 24-year-old reserve ranger Muhammad Hafizudin Mohd Sarpar told Al Jazeera later that evening.

But such scenes may soon be a thing of the past, as Malaysia’s already endangered sea turtles face new threats from rising temperatures caused by climate change. Scientists in the Southeast Asian nation say high temperatures are warming the sand, disrupting the balance of male and female hatchlings that turtles rely on to survive.

Observations at Chagar Lake Pond, one of the most important nesting sites in the country, show that very few male turtles have hatched from their nests in recent years. The situation is similar at other East Coast beaches.

Mohd Uzair Rusli, a turtle expert at Universiti Malaysia Terengganu (UMT), said that from 2019 to 2022, the number of male turtles hatched in many areas on the peninsula’s east coast was almost zero.

With global warming, this will result in males being unable to hatch.

The eggs laid by sea turtles incubate in the sand for up to 60 days and are extremely sensitive to temperature.

At temperatures of 29.2 degrees Celsius (84.6 degrees Fahrenheit), green turtle nests contain an equal proportion of males and females, but a one-degree change in temperature can completely change the sex of the hatchlings.

This narrow range is thought to be an evolutionary adaptation that balances the advantages of producing males and females, Uzair said.

He added that beach temperatures in Malaysia are not monitored because sea turtles nest in random locations even on the same beaches, and the UMT has relied on sea surface temperature reports for decades.

These turtles will grow up and return to the same beaches where they hatched to lay their eggs, but they already face huge challenges. On average, only one in 1,000 hatchlings survive the 15-year journey to adulthood. Uzair worries that as temperatures rise, Malaysian waters may one day not have enough males to mate with females.

“We predict that if we still don’t see males hatching, maybe in about 10 to 15 years, turtles may lay eggs but they won’t hatch,” he said.

Malaysia is home to four species of sea turtles, with thousands of them visiting the country’s beaches every year, especially in Terengganu state.

Their numbers have been declining for decades, largely due to human activity, from fishing to pollution and habitat loss, as well as people stealing their eggs to eat.

As sea turtle numbers decline, environmentalists are rushing to help Malaysia’s turtle population recover.

In 1993, the isolated 350m-long Chagar Lake Beach was selected by the authorities as a protected area and managed by UMT, with a volunteer program established a few years later.

Since then, the university has been recording the turtles’ arrival and relocating the nests away from predators, monitoring the lizards’ preference for turtle eggs as well as threats from humans.

Their efforts paid off. From a few hundred nests per year in the 1990s, by 2022, the number reached a record 2,180 nests.

But their success has been overshadowed by global warming and other man-made factors.

According to the National Oceanic and Atmospheric Administration (NOAA), daily sea surface temperatures in March reached a record high of 21.07 degrees Celsius (69.93 degrees Fahrenheit).

NOAA said last month was also the warmest March in 175 years of climate data and warned there is a 99% chance that 2024 will rank among the top five warmest years on record.

Oceans cover 70% of the earth and absorb 90% of the excess heat produced by the carbon dioxide and methane emissions from the burning of coal, oil and natural gas.

plastic

Plastic compounds the problem. Improperly managed waste floating in the ocean eventually washes ashore, absorbing more heat and releasing it into the sand.

Volunteers have been working hard to clear away the rubbish.

One morning in late March, students and university staff gathered at Chagar Pond to clean up the beach. In one morning, they collected enough garbage ropes, nets and plastic from the South China Sea to fill several small boats.

Jonas Goemans, a 22-year-old Belgian student, told Al Jazeera that we were not close to all the rubbish and that it was only a few hundred meters from the shoreline. The team put the rubbish into bags and loaded them into A larger ship for processing.

“It’s terrible, especially to find it in a place that’s supposed to be a shelter,” Gomans said.

A 2023 study from Florida State University found that large amounts of microplastics (plastic fragments less than 5 millimeters (0.2 inches) in length) could significantly increase the temperature of beach sand.

The study found that samples at a 30% concentration contained nearly six times the highest reported levels of black microplastics and were 0.58 degrees Celsius (33 degrees Fahrenheit) warmer than uncontaminated sand.

Some studies suggest cooling nests by shading them with sand, although doing this for hundreds or even thousands of nests would be difficult. Larvae nesting under trees may become entangled in tree roots and may become targets for invasive ants.

Inadequate artificial shading can also prevent rainfall from cooling hot beaches, while too much water that cannot evaporate quickly enough can lead to fungal infections in nests.

Nicholas Tolen, a researcher and doctoral student at UMT, says it takes a lot of effort to ensure that nests are managed at cooler temperatures to produce hatchlings.

extremely important role

Sea turtles have been around since the days of the dinosaurs and play a vital role in the world’s oceans and marine food chains.

For example, leatherback turtles control jellyfish populations, while green sea turtles feed on seagrass beds, stimulating the growth of these saltwater plants.

Among other things, seagrass helps clean surrounding waters, reduces coastal erosion and provides habitat for small fish and other marine species.

Even before the climate crisis, fewer sea turtles were landing in Malaysia, especially leatherback turtles, the world’s largest sea turtles and considered critically endangered.

Uzair said the last two leatherback turtle nests found in Terengganu state were recorded in 2017, and the eggs in both nests were found to be unfertilized. In 1953, there were approximately 10,000 nests, according to NOAA.

Only a few locations around Malaysia still see large numbers of turtles coming ashore, and the total number of landings is much lower than in previous generations.

Even in Chagar Lake, only green turtles land in large numbers every year, and a small number of hawksbill turtles land ashore. Green sea turtles are considered an endangered species, while hawksbill turtles are listed as critically endangered.

Hafizuddin said he could not imagine Malaysia without turtles.

A Redang local himself, he said tourism is the island’s main source of income, with tourists coming mainly to catch a glimpse of its marine reptiles.

They are like my brothers and sisters. Like my second home.When I became a ranger, I developed these feelings for them, especially when I learned that they were [in danger] Imminent extinction, he said.

If there weren’t turtles, tourists wouldn’t come. There won’t be any appeal.