BENTON — For the first time since 2019, residents, vendors and visitors flocked to the Benton Alewife Festival on Saturday to celebrate the native fish’s resurgence in recent years.

The festival began in 2012, but was canceled for a few years due to the coronavirus pandemic. It celebrates the annual alewife migration, when the fish travel upstream for about a month in the spring to reach lakes and ponds to spawn.

“We’re hoping to continue bringing a greater awareness to the importance of the alewives and the Sebasticook River, and also to come together as a community,” said organizer Amy Gagnon earlier this week.

Festivalgoers congregated Saturday at the Benton Riverside Park by the town hall to browse stalls offering food, canned goods, wood carving demonstrations and information on local wildlife including alewives. People could then migrate down a walking path from the park to the Benton Falls Dam for a tour of the fish lift at the dam. Live music from bluegrass band The Oystermen provided the day’s soundtrack.

At Benton Falls, tens of people at a time lined the dam, leaning over the railings to catch a glimpse of the millions of fish passing over using a fish elevator.

It’s a recent marvel: for decades, alewives’ migration up the Sebasticook River was blocked. In 2008, the fish population at Benton Falls was estimated at just 400,000.

But the removal of the Edwards Dam on the Kennebec River in Augusta and the Fort Halifax Dam in Winslow, along with other restoration efforts, now allow the fish to travel up again. In 2022, there were an estimated 2.7 million fish counted at Benton Falls Dam, according to the Maine Department of Marine Resources.

Festivalgoers were eager to celebrate that fact on Saturday for the first time in years.

“It’s good to have these kinds of community events opening up again,” said Benton-based forest ranger Timothy Kjellman. Kjellman was on hand to represent the Maine Forest Service and teach local kids about fire safety and wildfire prevention.

A couple vendors had made an annual appearance at the festival before it was suspended, including wood carving instructor Steven Valleau, an artist-in-residence at the Wendell Gilley Museum in Southwest Harbor.

“I feel like now I’m back here, COVID is officially over,” Valleau joked. “It’s awesome.”

Also returning with a stall were representatives from the Sebasticook River Land Trust, on hand to explain to people headed down to the falls the importance of alewives to the area, and raise awareness about ongoing conservation efforts across the watershed.

Doug Wescott, a land trust board member, said that alewives are hugely important to the region’s watershed.

“There’s a big issue in a lot of lakes in Maine with phosphorus,” Wescott said.

Phosphorus is an essential nutrient for plant life but when there is too much of it in water it can speed up something called eutrophication, which causes a dense growth of algae and depletes oxygen levels.

Alewives, Wescott said, eat the algae produced by excess nutrients in the lake like phosphorus, effectively cleaning up the lake and mitigating the potential for an algal bloom.

The removal of the dams was a godsend to the Sebasticook River watershed, Wescott said. “They were interfering with natural processes … I don’t think anyone knew at the time how many alewives would come here.”

Since then, the Sebasticook has become one of the biggest alewife runs on the East Coast. Wescott said that the 5-mile section of the Sebasticook River in Benton and Winslow has become the area with the largest concentration of bald eagles on the East Coast.

“And it’s all because of the alewives,” he said.