New eDNA tech locates animals in the wild in real-time

The Swinhoe’s softshell turtle has long captivated conservationists because of its rarity and uncertain future. This freshwater reptile, also called the Yangtze giant softshell turtle, has only two confirmed individuals left on the entire planet.

Scientists have been searching far and wide to locate more. The latest tool in their arsenal is environmental DNA (eDNA) technology, which has shown promise in previous studies on amphibians and fish by detecting genetic remnants left behind in water samples.

eDNA test for rare turtles

Swinhoe’s softshell turtle lives in large waterways, and releases traces of genetic material into the water through urine, feces, and sloughed skin. The challenge is enormous because these particles disperse quickly and degrade over time. 

Researchers needed a test that could identify minuscule DNA fragments right at the water’s edge. Tim McCormack, Program Director of the Asian Turtle Program of Indo-Myanmar Conservation (ATP-IMC), began investigating eDNA applications in 2013.

Sensitive and specific kit

Researchers have now launched a portable eDNA system that relies on quantitative polymerase chain reaction (qPCR), an established method for pinpointing species-specific DNA.

There had been previous success in laboratory settings, though the wait time for results was often long. Field teams wanted speed and accuracy in places with limited equipment. 

“Our early data showed the feasibility that eDNA testing could be used to detect this turtle species in its natural environment,” said Tim McCormack at the end of his initial trials.

Real-time field results

Traditional eDNA methods have required sending water samples to specialized laboratories, where the analysis might take weeks.

That gap proved frustrating for surveys aiming to verify the presence of a rare species. This new portable approach compresses the timeframe significantly. 

A 2014 review suggested that eDNA could reshape conservation efforts by making the detection of elusive species more efficient. With this test, the field team can sample water, filter it, and run the qPCR analysis onsite. 

“The portable eDNA test has allowed conservationists to be trained in and carry out the qPCR testing in real-time on the ground,” explained Dr. Minh Le, Head of Department of Natural Resources and Conservation at Vietnam’s Central Institute for Natural Resources and Environmental Studies (CRES), at the end of a demonstration project.

Why it matters

Swinhoe’s softshell turtle has persisted in pockets of Vietnam and China, yet little is known about these hidden populations.

One documented individual lives in Vietnam’s Dong Mo Lake, a 3,000-acre body of water that had confounded researchers in the past. Another resides in captivity in China. 

Attempts at breeding have faced setbacks, and a female turtle died in 2019. Without additional turtles, the future of this species looks bleak.

This new test is expected to guide survey teams in checking undervalued habitats, such as lesser-known lakes and reservoirs, with a level of speed not seen before.

Success of eDNA test on a turtle

Researchers recently validated the portable kit’s accuracy by detecting eDNA from a living turtle in a large waterbody near Hanoi. 

“This project proved that we could use eDNA to detect an extremely rare species in a very large lake, and demonstrates that portable eDNA testing can be applied as a conservation tool to help detect the rarest of the rare of species in a natural environment. This is truly groundbreaking for conservation research,” said Dr. Tracie Seimon, Director of the WCS Zoological Health Program’s Molecular Laboratory and lead author of the project’s paper.

The technology also lowers costs. Conservationists can pool multiple water filters before a single test, covering broader areas with fewer resources.

The results appear swiftly, which enables them to decide whether they should concentrate further effort in any positive location.

Future of eDNA tests for turtles

Teams in Vietnam plan to continue scanning far-off lakes and little-known reservoirs for signs of the Swinhoe’s softshell turtle.

“By finding other individuals, we may succeed in our overall goal, which is to prevent the species from going extinct,” said Thuy Hoang, Director of WCS Vietnam, at the end of a talk at CRES. Even the discovery of one more turtle could push conservation steps forward.

Field teams are hopeful that other institutions will adopt the same strategy for other endangered species, since eDNA detection works for many life forms. This might include cryptic fish, amphibians, or even mammals in tricky habitats.

Refining strategies

Some improvements may still be needed.

Scientists are testing the kit’s resilience in different water conditions and investigating how to preserve filter samples for extended trips.

They also see value in pairing the eDNA method with established survey practices, such as visual observations and local knowledge. 

Collaborations across borders continue because conservation initiatives are rarely confined to a single country’s waterways.

Local communities have shown interest, particularly when they learn that sampling is quick and non-invasive. There’s no need to catch or disturb an animal.

Once the presence of the target eDNA is confirmed, researchers can decide whether more involved steps, such as camera traps or small-scale capture attempts, are justified.

Hope on the horizon

Many face frustration and weariness from years of searching for this turtle. The portable eDNA test is bringing fresh optimism for turtle conservation.

The two known Swinhoe’s softshell turtles might soon be joined by relatives if this tool is successful in uncovering hidden pockets where they survive.

Though the timeline remains uncertain, conservationists believe that persistence and collaboration will improve the species’ outlook.

There is excitement about applying this simple, rapid, and targeted solution to other emergencies in wildlife protection.

The study is published in Environmental DNA.

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