Context:

• It is not only humans who are blessed by the sacred waters of temple ponds across the northeast of India. These protected water bodies have now emerged as safe havens for many threatened species of freshwater turtles, including the Nilssonia nigricans or Black Softshell turtle, declared extinct in the wild by the IUCN Red list.

environmental DNA (eDNA):

• However, given their ritual nature, scientists do not have complete access to these ponds and hence have used the technique of extracting environmental DNA (eDNA) to confirm the presence of specific varieties.
• In addition to N. nigricans, tests at the Nagshankar temple pond in Assam have confirmed the presence of two more species — Nilssonia gangetica or Indian softshell turtle, classified as Vulnerable and the Chitra indica or South Asian narrow-headed softshell turtle, listed as Endangered by the IUCN.
• On the global use of eDNA technology, he gave the example of the Yangtze Giant softshell turtle (Rafetus swinhoei) found in China and Vietnam and said scientists are using the technology to find out at least one male turtle in the wild so that the species of most threatened freshwater turtle can be saved.