Scientists using DNA to help preserve elusive fish
Char prized by anglers, threatened by predators
PORTLAND, Maine — Scientists in Maine are using DNA to try to preserve the remaining populations of a fish that lives in 14 lakes and ponds in the state and nowhere else in the continental United States.
The scientists are turning their eye to the arctic char, a species of landlocked fish in Maine that has lived in the state for millennia and is prized by anglers. The char faces threats such as invasive predators and a warming climate. It is also notoriously elusive, making it difficult for researchers to track.
Michael Kinnison, a professor of evolutionary applications at the University of Maine, and other scientists are working with the state to make sure the fish keep surviving. Kinnison is working on a project to collect “environmental DNA” from the water bodies where the fish live.
The project involves collecting water samples from the lakes and ponds where the fish are known to live, and studying DNA that they and other organisms shed, Kinnison said. It’ll provide vital information scientists can use to keep char populations stable, he said.
It’s also a much less invasive and time-consuming way than older methods, such as using nets, Kinnison said.
“If your only tool to count a species is a gillnet, and there’s not many, do you make the tough choice to risk killing the individuals to find them?” he said. “It’s a way to get an idea of where organisms are located and do it in a way that presents really no harm.”
Arctic char live at the top of the world, including in northern Canada and Alaska. They’re known to seafood lovers because they’re farmed for use as food. But to find one in the lower 48 states, an angler can only go to one of a group of remote, rural ponds and lakes in Maine, some of which are barely accessible to humans.
The project to collect their DNA in Maine launched in 2017, and is expected to continue through this summer, said Brad Erdman, a University of Maine ecology graduate student who is working on it. A local chapter of Trout Unlimited, an environmental nonprofit, is working on the project using grant money provided by the organization’s Embrace-a-stream fund.
One of the biggest threats to the char is the presence of invasive rainbow smelt, a small fish that competes with the char for food and is suspected of eating char young. A yearslong project to eradicate the smelt from Big Reed Pond in northern Piscataquis County was meant to save the char population there.
Using environmental DNA can help make sure the smelt don’t gain a foothold in other bodies of water where the char live, said Francis Brautigam, the director of fisheries for the state wildlife department. The smelt have been illegally introduced in Bald Mountain Pond in northeast Somerset County, where char populations have dropped, he said.
“Our agency has been pretty responsive to ensuring those populations remain on our landscape,” Brautigam said.
Igor Sikorsky, a northern Maine camp owner and air taxi bush pilot, worked with the state on efforts to save the char population on
Big Reed Pond. He said the move toward using advanced tools such as environmental DNA is a smart one, because the fish are a unique part of the state’s natural landscape.
The fish like cold water, and they’re at the very southern end of their range in Maine.
“Who knows if this is the end, or if we are able to stabilize it,” Sikorsky said. “So far, so good is the best you can say.”
In this Oct. 26 photo, University of Maine graduate student Brad Erdman holds an arctic char, left, and a brook trout at Floods Pond near Otis, Maine. Scientists in Maine are in the middle of a project that uses DNA to help preserve the char.