Male hatchlings feel the heat and swim to extinction in Malaysia | Climate Crisis News

Redang Island, Malaysia – Under a full moon, bulbous creatures emerge from the South China Sea onto the secluded beaches of Malaysia’s Redang Island.

Watched closely by a team of volunteers, the green sea turtle slowly moves across the fine white sand to the top of the beach, using its flippers to dig into the sand before laying its precious eggs.

Lifeguards at the Chagar Hutan Sea Turtle Sanctuary in northeastern Terengganu state stalk around, recording and counting the number of sea turtle eggs nesting on the sand.

“Redan is famous for its turtles. We want to protect our treasure here,” Mohammed Hafizuddin Mohd Sarpar, 24, a ranger at the reserve, told NDMT a little later that evening. Ta.

But such scenes may soon be a thing of the past, as Malaysia’s already endangered sea turtles face new threats from rising temperatures due to climate change. Scientists in the Southeast Asian country say the heat is warming the sand and disrupting the balance of male and female hatchlings that turtles need to survive.

A ranger from the Chagar Hutan Turtle Sanctuary monitors the eggs laid by green sea turtles nesting on the shore, while university students and staff watch on. [Patrick Lee/NDMT]

Observations at Chagar Khutan, one of the most important nesting sites in the country, indicate that very few males have hatched from the nests in recent years. It’s a similar story at other beaches along the East Coast.

“From 2019 to 2022, the number of hatched male turtles is almost zero in many areas on the peninsula’s east coast,” said Mohd Uzair Lusli, a turtle expert at Universiti Malaysia Terengganu (UMT). Stated.

“Global warming will prevent males from hatching.”

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

At 29.2 degrees Celsius (84.6 degrees Fahrenheit), green sea turtle nests have an equal proportion of males and females, but a 1 degree change in temperature can shift the sex of hatchlings in one direction or the other. It can change completely.

Uzair said this narrow range is thought to be “an evolutionary adaptation that balances the advantages of producing both males and females.”

He said given that turtles nest in random locations even on the same coast, temperatures on Malaysian coasts are not monitored and the UMT relies on decades of sea surface temperature reporting. He added that there is.

Once fully grown, turtles returning to the same beaches where they were hatched to lay their eggs already face major challenges. On average, only one out of every 1,000 hatched turtles survives the 15-year journey to adulthood. Uzair worries that rising temperatures may one day reduce the number of males enough to mate with females in Malaysian waters.

“If we cannot see the male hatching yet, perhaps after 10 to 15 years, we expect the turtles may lay eggs but they will not hatch,” he said.

Malaysia is home to four species of sea turtles, and Terengganu’s beaches in particular once attracted thousands of marine reptiles each year.

Their numbers have declined in recent decades, primarily as a result of human activities, including fishing, pollution, habitat loss, and even humans stealing and eating their eggs.

As turtle numbers dwindle, environmentalists are racing to help Malaysia’s turtle population recover.

A group of men in shorts and T-shirts loading large racks of garbage bags onto a small boat near the beach. The sea is clear.
Debris is also a big problem for turtles, so cleaning is done regularly. [Patrick Lee/NDMT]

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

Since then, the university has continued to document the turtles’ arrival and how the monitor lizards relocate their nests from natural predators that favor their eggs, as well as human threats.

Their efforts paid off. In the 1990s, there were a few hundred nests each year, but in 2022 there were a record 2,180 nests.

But their success is being overshadowed by global warming and other human-induced factors.

March set a record daily sea surface temperature of 21.07 degrees Celsius (69.93 degrees Celsius), according to the National Oceanic and Atmospheric Administration (NOAA).

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

Oceans cover 70 percent of the Earth and absorb 90 percent of the excess heat produced by carbon dioxide and methane emissions produced by the combustion of coal, oil, and natural gas.

plastic

Plastic is making the problem worse. Improperly managed waste floating in the ocean ends up on shore, where it absorbs even more heat and releases it into the sand.

Volunteers are working to remove trash.

A group of people move a large amount of discarded fishing nets into a small boat. The net is green and gray and has knots.
Tangled chunks of nets washed ashore from the South China Sea are loaded onto large ships and disposed of on the mainland. [Patrick Lee/NDMT]

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

“We couldn’t get close to all of it, it was just a few hundred meters from the coastline,” said visiting Belgian student Jonas, as the team bagged the waste and loaded it onto a larger boat.・Gomans, 22, told NDMT. It will be disposed of on the mainland, about 50 kilometers (31 miles) away.

“It’s horrifying, especially when it’s found in what’s supposed to be a sanctuary,” Gormans said.

A 2023 study from US-based Florida State University found that the presence of large amounts of microplastics, which are pieces of plastic less than 5mm (0.2 inches) long, could cause the temperature of coastal sand to rise deadly. It turned out that there is.

The study found that samples with a 30 percent concentration of black microplastics (almost six times the highest amount reported) had temperatures 0.58 degrees Celsius (33 degrees Fahrenheit) warmer than sand that was not contaminated with plastic. found.

Some studies suggest shading the sand to cool the nesting sand, but this is difficult to do for hundreds or even thousands of individuals. Nesting under a tree runs the risk of the chicks getting entangled in the roots, which can make them a target for invading ants.

Improper artificial shade may also prevent rain from cooling hot beaches, but it can also cause fungal infections in the nest if excess water cannot evaporate quickly enough.

“It will take a huge effort to be able to manage nests to produce hatchlings at lower temperatures,” said UMT researcher and PhD student Nicholas Tholen. ” he said.

important role

Sea turtles have been around since the time of the dinosaurs and play an important role in the world’s oceans and marine food chains.

For example, leatherback turtles control jellyfish populations, and 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 life.

A turtle lays eggs on the beach and then crawls back to the sea. In front of the turtle is the sea.There are some rocks in the water and a cliff covered with trees in the background
A female green sea turtle returns to the sea after laying eggs at Chagar Hutan Beach [Patrick Lee/NDMT]

Even before the climate crisis, Malaysia was seeing fewer and fewer landings of turtles, especially the world’s largest turtle, the leatherback sea turtle, which is considered an endangered species.

Uzair said the last two leatherback nests found in Terengganu were recorded in 2017 and both eggs were found to be infertile. According to NOAA, there were about 10,000 nests in 1953.

There are still only a few places across Malaysia where turtle landings are seen in large numbers, and the total number of landings is much lower than in previous generations.

At Chagar Hutan, only a few hawksbill turtles land each year, and only green sea turtles land in large numbers. Green sea turtles are listed as endangered and hawksbill turtles are listed as endangered.

Hafizuddin says he can’t imagine Malaysia without turtles.

A local himself on Redang Island, he says tourism is the island’s main source of income, and tourists mainly come to catch a glimpse of the sea reptiles.

“They’re like my brothers. They’re like my second family. When I became a ranger, especially when I found out they were them, I felt this way towards them. I had a feeling. [in danger] It could go extinct,” he said.

“If there are no turtles, tourists won’t come. It loses its charm.”

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