Sci­en­tists hop­ing DNA in wa­ter helps pre­serve rare fish


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 charr, which is a species of land­locked fish in Maine that has lived in the state for mil­len­nia and is prized by an­glers. The charr face threats such as in­va­sive preda­tors and a warm­ing cli­mate. They are also no­to­ri­ously elu­sive, mak­ing them dif­fi­cult for re­searchers to track.

Michael Kin­ni­son, a pro­fes­sor of evo­lu­tion­ary ap­pli­ca­tions at 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 charr 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 charr 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 Em­braceA-Stream fund.

One of the big­gest threats to the charr is the pres­ence of in­va­sive rain­bow smelt, a species of small fish that com­petes with charr for food and are sus­pected of eat­ing charr’s young. The charr were the sub­ject of a years­long project to erad­i­cate the smelt from Big Reed Pond in north­ern Pis­cataquis County to save the charr’s pop­u­la­tion there. Maine Depart­ment of In­land Fish­eries and Wildlife con­firmed in June 2017 that the charr are spawn­ing in the pond again.

Us­ing en­vi­ron­men­tal DNA can help make sure the smelt don’t gain a foothold in other bod­ies of wa­ter where the charr 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 charr pop­u­la­tions have dropped, he said, and con­trol­ling the sit­u­a­tion is a pri­or­ity.

“Our agency has been pretty re­spon­sive to en­sur­ing those pop­u­la­tions re­main on our land­scape,” Brautigam said.

“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.”

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