As thousands of river herring begin their upstream migration this month, runners will do the same. Joggers on May 23 will pace the alewife run from the Passamaquoddy Reservation at Sipayik (Pleasant Point), 80 miles up the St. Croix River to Forest City in Washington County.

The St. Croix River, known as the Skutik River to the Indigenous people of northern Maine and southeastern Canada, was once a vital migratory highway for tens of millions of alewives, said Brian Altvater Sr.

The fish are born in lakes in the spring, then head toward the ocean by summer’s end. After three years, or up to five, they return upstream to spawn in lakes.

Altvater, a passionate runner for most of his life, is a founding member of the Schoodic Riverkeepers and the wellness coordinator for Wabanaki REACH, the nonprofit that hosts the race.

From whales to eagles to eels to people, alewives are known as the fish that feeds all (they make excellent lobster bait, too).

Altvater, who is Passamaquoddy, is inclined to wax poetic on the harbinger of spring that alewives must’ve been for his people.

“Just think of an incredibly cold winter — and you know, there’s no grocery stores or anything like that — so just think what a welcome sight the fish, the alewives coming up the river would be,” he said. “With the fiddleheads and other things cropping up, I mean, they must’ve been in heaven.”

For decades, Altvater has advocated restoration of the Skutik River to a thriving fish habitat. The Milltown dam, in Calais, was removed in 2023 and was the first of three blockades along the river isolating the alewives from the river’s headwaters.

An ongoing $58 million project, a partnership between federal, state and tribal governments as well as nonprofits and businesses, will improve the fishways on the Woodland and Grand Falls dams that remain above Calais.

Nearly half a million alewives traveled through the Grand Falls dam fish passage last year — a far cry from the millions that once fluttered upriver, but more than double the fish counted in 2022, before the Milltown dam was removed.

The Skutik River Alewife Run, which Altvater started in 2012, invites people to connect with the keystone species. Runners and walkers of all ages will gather at Split Rock in Sipayik at 5 a.m. later this month and start the 80-mile journey.

Along the way, runners will trade in and out as the event makes its way to Forest City, with a break on the Passamaquoddy Reservation at Motahkomikuk (Indian Township). Last year, the event had some 40 participants.

Participants run or walk as far as their legs will carry them, said Altvater, who described the race as a communal effort to make it to Forest City by early evening. The run is open to the public, and people can sign up on Wabanaki REACH’s website.

The fish will start to slowly make their way up streams later this month. Fish-seekers can observe the migration statewide, including at the Mill Brook Preserve along the Presumpscot River in Westbrook, at the Brunswick dam observation room on the Androscoggin River (Wednesday through Sunday, 1-6 p.m.) and at Damariscotta Mills in Nobleboro.

Reuben M. Schafir is a Report for America corps member who writes about Indigenous communities for the Portland Press Herald.