Since the 1999 breach of its Edwards Dam, the Kennebec River has seen river herring runs more than two million fish strong, and many river-watchers hope that will foreshadow what can happen here. “The potential here is much bigger,” said Laura Rose Day, the executive director of the Penobscot River Restoration Trust, which says the river could eventually see runs of four million to six million river herring.

Image Credit... The New York Times

The ultimate success of the population will be contingent on what happens to them during their time in the ocean, which no one here can control. And they will also need access to the lakes where they like to spawn — some of which have small dams and human neighbors who might be resistant to river herring populations, which have an erroneous reputation for being invasive.

“You’ve got the dams out, which is a huge chunk of the issue — now we need to get access into the lakes,” said Karen Wilson, an assistant research professor at the University of Southern Maine. “People are working on that, but it’s going to take more money and more support from the public.”

And if river herring do rebound here, they could help the endangered Atlantic salmon do the same, because an abundance of river herring helps shield salmon from predators. In the late 1800s, fishermen commercially harvested 100,000 salmon from these waters, but no one is allowed to fish for them here anymore. The Trust said 372 Atlantic salmon had been counted at the dam this year; its removal could eventually help that number grow to 12,000.

“It’s exciting, the fact that salmon can potentially get back,” said Mathias Deming, 15, of Winthrop, Me., who was listening to tales from group of older anglers after Monday’s dam breach.

Chief Kirk Francis of the Penobscot Indian Nation, said some members of his tribe had made new fish spears in the hopes that they might soon be able to fish for salmon for the first time since 1985, resurrecting tribal practices.

“I think we’ll come back to a balance, where the river is doing well,” he said. “It’s historic when a lot of people have lived and died seeing its demise.”