Spot a Snot Otter with Just a Water Sample

Biodiversity Tracking Using Environmental DNA is Gaining Ground

If you want to protect rare species, or confirm the presence of an invasive species, first you have to find them. In the past few years, biologists have developed a powerful new tool– environmental DNA, also known as eDNA.

At THI we are always on the lookout for new technologies that can assist the work that we do, and this exciting approach opens new perspectives for the assessment of current biodiversity and in detecting trends in biodiversity from environmental samples.

In 2008 French and Italian scientists published research showing success in detecting invasive American bullfrogs simply by sampling pond water and looking for an exact genetic match to the frogs’ DNA.

According to a story on National Public Radio (NPR), sampling for eDNA has also been used to confirm the presence of rare species like Appalachia’s hellbender salamander, nicknamed the “snot otter,” because it grows to up to two feet long and is covered with slime.

Conservationists can extract DNA from the water and know if the elusive snot otter is in a particular stream without lifting a rock, and can even tell by increased amounts of eDNA the particular streams where the salamander may be breeding.

A common target of eDNA sampling is the invasive Asian carp. Water samples collected in summer 2011 in Maumee Bay, Michigan tested positive for the dreaded carp. The Asian carp has traveled rapidly toward the Great Lakes from the southern areas of the Mississippi River and officials fear the fish could devastate the Great Lakes fishery if they were to establish a breeding population in the lakes.

In May 2012 the U.S. Army Corps of Engineers reported the agency’s successes in decreasing eDNA processing time and costs when sampling for the presence of Asian carp, and wrote, “Although eDNA is a relatively new tool for aquatic vertebrate detection, we were excited by the potential that this technique has for sampling both rare and invasive species.”

Early testing has proven useful and cost effective in the fight to preserve biodiversity in our nation’s lakes and waterways. New tools for the toolbox are always needed as we fight to save the freshwater resources we all share.