Pig-nosed turtle numbers have plummeted dramatically in the past 30 years, according to new research published in the journal Biological Conservation.
A unique reptile, the pig-nosed turtle has become an international conservation icon due to its unusual evolutionary history, morphology, ecology and behaviour.
The sole survivor of a once widespread family of turtles called the Carettochelyidae, the pig-nosed turtle has a restricted global distribution, being only found in north Australia and New Guinea Island.
However, despite its uniqueness, this species is highly prized as food, and the demand for its eggs and meat in Papua New Guinea has led to the species being dramatically over-harvested by indigenous people. Both turtle and eggs are collected for trade or consumption by local villagers.
To find out what impact such harvesting may be having on the turtle, Professor Carla Eisemberg of the University of Canberra, Australia, surveyed the numbers of eggs and adult turtles nesting in the Kikori region of Papua New Guinea. The number of turtles and eggs passing through local markets were also studied, as well as the consumption of turtles in villages along rivers and the coast.
The data was compared with a similar study of the pig-nosed turtle that was carried out between 1980 and 1982 by Mark Rose, a scientist at Fauna and Flora International in Cambridge, UK.
The similarities of the two studies meant that Professor Eisemberg and her team were able to directly compare how the turtle has fared over the past 30 years, with the results showing more than a 50% decline in pig-nosed turtle populations in the study region since the 1980’s.
The researchers found that villagers harvested more than 95% of nests that were monitored during the study. They also discovered that female turtles have become smaller on average as bigger individuals have been removed from the wild population, while the overall life expectancy of the species has also fallen.
The team fear that the 50% population decline observed in the study area since the 1980s is likely to be widespread throughout Papua New Guinea, as the species is under similar pressures elsewhere in the country.
According to the scientists, conservation plans to save the turtle are urgently needed, and, even if implemented, it will take decades for the pig-nosed turtle to recover. However, the indigenous communities living alongside pig-nosed turtles often rely on protein from the reptile to survive, meaning that planning for its conservation is a delicate balancing act.
“We need to provide win-win outcomes to both local and conservation communities,” said Professor Eisemberg.
Find out more about the pig-nosed turtle.
Helen Roddis, ARKive Species Text Author