Mystery as Giant Dead Turtle Discovered on Beach

A rare and endangered leatherback sea turtle has been found washed up on a beach, with wildlife officers unsure what caused its death.

The Australian Registry of Wildlife Health, a research program, at Taronga Zoo took in the turtle after it was discovered on March 5 on Whale Beach in the north of Sydney, Australia.

They will perform a necropsy on the creature to determine the cause of death, but due to the degree to which the body had decomposed, a spokesperson from the National Parks and Wildlife Service has said that the post mortem may take several weeks to complete, Australian ABC News reported.

Leatherback sea turtles, or Dermochelys coriacea, are the largest species of turtle in the world, growing up to nearly 6 feet long and weighing 1,100 pounds. They are listed as "vulnerable" worldwide by the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, but are categorized as "endangered" locally in the Northwest Atlantic Ocean, and "critically endangered" in the Southwest Atlantic Ocean, Southwest Indian Ocean, West Pacific Ocean and East Pacific Ocean subpopulations.

This death comes mere days after another leatherback turtle was saved from being entangled in a shark net off Australia's Central Coast on Friday. However, this turtle was subsequently microchipped while the Whale Beach turtle was not, meaning they are different turtles.

This isn't the first time that these beautiful creatures have been found dead near Sydney: the New South Wales National Parks and Wildlife Service said six leatherbacks washed up dead on the beaches of the Central coast in quick succession this time last year.

Leatherback turtle populations have been declining rapidly over the past few decades, with the National Oceanic and Atmospheric Administration (NOAA) estimating that the total number of turtles has dropped by 40 percent over the past three generations. Leatherback turtles are thought to live around 50 years in the wild, and reach sexual maturity between the ages of 9 to 20 years old.

Worldwide, between 26,000 to 43,000 females were thought to remain in the wild as of 2007, compared to the 115,000 females that were estimated in 1980.

Leatherbacks face a number of threats that are contributing to their declining numbers, including egg collection. Females often travel thousands of miles to breed and lay their eggs, digging a hole in the beach and laying around 80 eggs under the sand. Many of these infants don't even make it to the sea, being picked off by predators as they make their way down the beach. Eggs are often harvested to eat or for their alleged aphrodisiacal powers, reducing the already limited number of baby turtles that survive until adulthood.

Additionally, NOAA states that human development on the coast in traditional egg-laying coastal areas has reduced the amount of sand available for the turtles to bury their eggs, and artificial lighting on the beaches has made it harder for the hatchling turtles to find their way to the ocean.

Adult turtles are also frequent victims of deliberate hunting for their meat, bycatch in fisheries for other species, and of being struck and killed accidentally by vessels.

Across all species of turtles, plastic pollution in the sea is a major issue: turtles often eat plastic wrongly thinking it is food and are subsequently poisoned or so filled up with plastic that they cannot eat nutritious food.

Turtles also frequently become entangled in plastic strands from fishing gear: one 2017 study by researchers at the University of Exeter in the U.K. found that 91 percent of the turtles found entangled in fishing gear worldwide were dead. Some leatherbacks have been found dead with up to 11 pounds of plastic inside their stomachs.

Entanglement in shark nets is a particular problem off the coast of Australia, as many of the beaches have nets stretching across the bay to prevent sharks approaching beachgoers. One Australian government report found that between 2021 and 2022, 11 leatherback turtles were caught in the shark nets off the Central Coast alone.

"A shark net is as useless as a volleyball net out in your front yard trying to stop a magpie from swooping in magpie season during spring," Marine Wildlife Rescue Central Coast founder Cathy Gilmore told ABC News.

Once the cause of death has been identified, the Australian Museum wishes to obtain the turtle's skeleton for its collection.

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