Minnesota Aquatic Invasive Species Research Center (MAISRC)
New eDNA degradation results suggest high potential for false negative detections of Asian carp, other species
With the publication of a new paper this month, MAISRC researchers announced new discoveries about the decay rates of environmental DNA (eDNA) and what it means for the detection of aquatic invasive species.
eDNA – genetic material that is released by an organism into its environment – can be used to detect a species without physically capturing it, making it popular for researchers who are studying rare or hard-to-find species. In Minnesota, the process has been used as scientists work to establish the presence of Asian carp in the Mississippi River watershed.
Using common carp as a surrogate for Asian carp in the lab, MAISRC researchers discovered that eDNA degrades very quickly in lake water: approximately 90% of it was undetectable after 24 hours under most conditions. This finding means that the chances of a false negative eDNA result — failure to detect a species when it is present — are perhaps greater than previously thought.
The researchers also found that temperature and water chemistry, specifically the concentration of dissolved organic carbon, affected the persistence of eDNA. Using previously published data on eDNA distribution in lakes, these results indicate that eDNA would be expected to persist for almost two weeks in winter as opposed to a few days in summer.
“This discovery doesn’t change the fact that eDNA is still a good method for detecting AIS,” said Eichmiller. “But it does impact how we interpret the readings.”