NORRIDGEWOCK — Off a remote dirt road that can only be accessed by another remote dirt road, more than a dozen fifth-graders from the Cornville Regional Charter School gathered on the banks of the Sandy River, stepping in and out of the water as they transferred cups of water from a cooler into the river.

Inside the cups were fish, each one no bigger than a paperclip.

Aven Hutchins, 10, of Cornville, explained that the odds for survival were not very good for the salmon fry, which the children were releasing Thursday as part of a larger salmon stocking program coordinated by the Atlantic Salmon Federation. Jodie Mosher-Towle, a program coordinator for the salmon federation’s Fish Friends educational program, said 60 schools across the state currently participate.

For each school, students learn about the salmon as they raise them from eggs laid and fertilized in a hatchery. The Fish Friends program comes with a curriculum that walks the children through the life cycle of the salmon. The kids ultimately release small batches of fish into freshwater locations that have been permitted under a conservation plan of the state Department of Marine Resources.

In all, Hutchins said, only two of every 650 fry that hatch in Maine’s fresh waters are expected to survive.

Still, Hutchins had a pretty good feeling about the chances of this particular batch of 200 fry, which he and his classmates had raised from eggs in a classroom aquarium.

“Between five and 200″ of the 200 fry were likely to survive into adulthood, Hutchins said.

In reality, the odds are discouragingly small that a stocked salmon fry will grow to adulthood, make it out to the ocean and then return to spawn as a mature adult in the Sandy River, a tributary of the Kennebec River.

Over the past 13 years, more than 400,000 fry have been stocked in the Kennebec, including 2,000 fry and 600 smolts last year.

As other states consider backing off their conservation efforts, Maine has increasingly become a leader of the salmon restoration movement. Last month, President Barack Obama appointed Maine’s Department of Marine Resources commissioner Patrick Keliher as commissioner of the Council of the North Atlantic Salmon Conservation Organization, an international group that seeks to restore salmon.

One piece of that puzzle is the Fish Friends Program, which has been supported by the Maine Council of the Atlantic Salmon Federation for about 20 years in the state.

Mary Stuart, a volunteer with the school, said she has participated in the restocking effort since 1996.

She said she’s nowhere near giving up on Maine’s salmon.

“It took us a long time to decimate them,” she said. “It’s going to take a long time to bring them back.”

As evidence that each year brings with it a better chance of success, she pointed to the remnants of a dam just a couple of hundred yards up the Sandy River from where the children were unloading their cups of salmon fry.

“When I first released them here, the water was brown and turbid,” she said. “I would think, ‘why am I doing this?'”

The clear, fast-running water at the site now is just one small improvement in the larger picture, she said. She said marine biologists are continually improving their release methods and learning more about what factors matter most in ensuring a successful run.

Since the U.S. Atlantic Salmon Assessment Committee began tracking return rates in 2005, the number of adult salmon that have been documented making it home has never been greater than 64, a threshold set in 2011, which was a banner year for salmon returns all up and down the Maine coast.

Re-establishing historic salmon runs to the Gulf of Maine has been a major goal of conservationists for decades.

By the mid-1800s, dams and pollution had destroyed a run of Atlantic salmon that was once estimated to be about a half-million fish each year.

Maine’s runs dropped in the 1990s from about 8,000 fish a year to about 2,000.

The salmon population in the Gulf of Maine received a theoretical boost in 2000, when it was protected by the Endangered Species Act. Since then, campaigns to remove or modify dams throughout the state have also opened up increasing amounts of salmon freshwater habitat.

Over the years, conservationists have put more than 324 million juvenile salmon, most of them fry, into New England rivers.

In 2013 alone, they stocked about 6.5 million juvenile salmon, including 5.5 million in New England.

Yet the salmon continue to struggle, and salmon stocking programs up and down the coast have been under pressure to show results that would justify the continued expenditure of resources. The last two years have been particularly discouraging.

In the Kennebec, 2010 and 2012 tie for the worst on record, with only five fish making it back up the Kennebec. In practical terms, last year was just as bad, with eight returning salmon.

The larger picture is no more promising.

According to the U.S. Atlantic Salmon Assessment Committee, across all of the Atlantic seaboard, the run was 2,340 in 2009 and 1,651 in 2010. In 2011, there was a promising run of 4,178, but the hopeful expectations prompted by that were dashed over the last two years, which saw discouraging numbers of 941 and 611, respectively.

The largest salmon run in the state is in the Penobscot River, which has a five-year average of 1,481 fish but saw only 381 in 2013.

Generally, experts say the fish do fairly well while living in river systems for the first two years of their lives. It’s when they head out to the Atlantic Ocean that things go wrong. For some reason not yet fully understood, not enough salmon are making back from the ocean to return and spawn.

In 2012, a 45-year-old program that had stocked 100 million fry into the Connecticut River ended, mostly because the population was just not taking root.

Programs in Massachusetts and New Hampshire are also under review for possible termination.

The volunteers involved with the Cornville school education program of the salmon federation said the point is to nurture two populations of small fry and usher them into maturity. The first are the 200 tiny fish that disappeared into the river, their chances at adulthood slim.

The second, and perhaps more important, Mosher-Towle said, were the students who watched them grow from eggs to fish before carrying them to the water. Salmon need humans who care for them, and that is a population that also needs to be restocked, she said.

“The hope,” she said, “is for the kids to become stewards.”

Matt Hongoltz-Hetling — 861-9287 [email protected] Twitter: @hh_matt