A Monroe resident used a citizen scientist approach to find evidence of brook trout in Basin Pond and Marsh Stream. Her method can help track fish and plant species in Maine waters, which could benefit state agencies monitoring Maine’s environment.

Jennifer Smith-Mayo used eDNA — DNA found in the environment from animals and organisms — to test Basin Pond in Monroe for brook trout in December 2019. She was unsure what she would find when she collected samples late last fall, she said. She found evidence of the species at one of four sites sampled and it points to the possibility of the fish residing in the pond and connected stream.

Smith-Mayo, who has traveled the world recording video and taking photos for documentary films, is currently working on a Ph.D. in communications from the University of Maine. She said she wants to improve communication about scientific research to the public. She is participating in research projects as a graduate research assistant while pursuing her degree.

While working on climate change adaptation research about brook trout in Maine, Smith-Mayo became curious to see if the species lives in Marsh Stream. From there, she contacted UMaine eDNA Core Facility Manager Geneva York for help sampling and testing for the fish.

Testing for eDNA is commonly done in soils, sediments and water, York said. It is organic material from the source animal that is shed, like skin cells from a fish, and contains DNA. This type of testing works best for animals in water, because DNA is easiest to collect in water.

York’s lab specializes in testing eDNA for researchers and citizen scientist groups mostly around New England, she said. At least half of the lab’s work is for non-governmental entities.

As an eDNA specialist, she advised Smith-Mayo about the best places to sample around the pond where the fish were likely to be and instructed her to take samples just under the surface of the water using sterile bottles.

The samples were taken just under the water column in places with good flow, which means the DNA likely had come off the fish within a couple days of collection, she said.

Her lab can offer to break down the DNA test based on the depth of results a person wants, York said. Lab costs vary by the amount of service required. It cost Smith-Mayo around $200 to have her samples tested just to detect the presence of fish DNA, which Smith-Mayo said she thought was reasonable and accessible to the public.

Brook trout and Waldo County

Smith-Mayo said she found trout DNA at the pond’s outflow site into Marsh Stream, which Fisheries Resource Supervisor Jason Seiders of the Department of Inland Fisheries and Wildlife said is not surprising.

The department’s Belgrade Lakes region, which encompases Waldo County, is the only area in the state that does not have even one lake or pond with a wild brook trout population, but has healthy populations in its streams and rivers, he said. Marsh Stream is known for wild brook trout.

Maine is the last stronghold for brook trout, which used to be plentiful in waters all over New England and south into the Appalachian Mountains, he said. But warming waters, invasive species and other developments have dramatically decreased the range of the native fish species.

There used to be wild brook trout in Basin Pond, but a 1998 survey found that the pond has a strong presence of chain pickerel and perch and that it should be maintained for warm water fish.

Invasive species are species that move into an area where they were not previously, causing a change in the ecosystem of a body of water. An invasive native species is a species already native to an area, but not found throughout the area. An invasive exotic species is a species not native to an area, but introduced because of outside circumstances.

Species like pickerel and perch, known as native invasive species, can compete with brook trout and stress the species when introduced into a body of water where they were not previously present, he said. But brook trout can still survive in the presence of the two invasive species.

Brook trout thrive in cold waters that would numb the human hand, Seiders said. But Maine waters are warming because of climate change and the cutting of trees along rivers and lakes that keep water cool with their shade.

Seiders said severe droughts, like the one during this past summer, can have a big impact on how well the species thrives. If streams dry up, the fish have no way to move from a warm body of water to a cooler one.

But he said he has seen some colonies of brook trout rebound after a bad drought as long as the habitat is still there and conditions the next year are good.

Smith-Mayo is concerned this year’s drought had a severe impact on the trout detected by her lab tests. She worries that those fish did not survive through the summer. She intends to repeat the tests in 2021 to see if she can detect the fish again.

“But I don’t know about this year’s trout, I really don’t know … After this summer I really have to wonder how they made it,” she said.

A future for citizen scientist work

Protections for the fish vary from one body of water to another, because some lakes are stocked well with brook trout, mostly in northern areas of the state, and some lakes have very few fish. The department runs its own citizen scientist program, which gives fishermen log books that are returned to the department to record what species are caught in waters where they fish.

The department also encourages people to send it photos of fish species that they are unsure about or that might be invasive, he said. His office is limited to three biologists for 300 lakes and 4,500 miles of streams in several counties, Waldo being one of them.

Citizen scientist work can help state scientists decide which lakes to survey each year and can let them know if an invasive species has been introduced to a waterway where the department was unaware of its presence.

Seiders encourages people who are curious about a fish they catch to take a photo of it or, if it is dead, to take it to the respective region’s fisheries office. He expects the citizen science field to grow. “I definitely see these opportunities expanding in the future, for sure,” he said.