Spring means animals of all kinds are looking for love — even fish. This month, thousands of silvery river herring are swimming from the ocean and up into Massachusetts’ tidal rivers to lay their eggs.
A diadromous fish, herring breed in freshwater and spend most of their lives in the ocean, where they make a tempting meal for striped bass and blue fish. Historically, herring were important food sources for Native Americans and early colonists. But much of herrings’ upstream pilgrimage, which is vital for maintaining populations, has been blocked by defunct dams left over from Massachusetts’ industrial past.
This year, herring in the Monatiquot River in Braintree will have an easier path to their spawning grounds for the first time in centuries. That’s because two dams that once powered rubber and cork factories — the Armstrong and Ames dams — were removed last summer. They were the final obstacles in a river restoration project decades in the making.
Herring can now travel from Hingham Bay into the Fore River, which becomes the Monatiquot, and snake along Route 3, swimming another few miles to reach the Great Pond Reservoir. The slow waters of the reservoir are a haven for egg laying. The spot has been out of reach since the first known version of a dam was built in this part of the river in the early 1700s.
“Everyone’s very excited with anticipation about fish passing through here this spring, really any day,” Brad Chase, biologist with the Division of Marine Fisheries, told GBH News in late April. Since that time, the DMF confirmed that herring have made it as far up as the Farm River, which feeds into the Blue Hills, just past the reservoir. Other species like shad, rainbow smelt and American eel are also expected to make the trek.
Chase said this particular herring run has been making a comeback since the 1980s, thanks to the passage of the 1972 Clean Water Act and improved water quality. In recent years, 5,000 to 10,000 herring have queued up at the base of the former dams.
“I really think if you look coast-wide, this has some of the highest potential among all restoration sites in coastal Massachusetts to increase diadromous fish populations,” Chase said.
The project rings in at $8.6 million, with a mix of private and public funding, including federal money from the National Oceanic and Atmospheric Administration, the U.S. Fish and Wildlife Service and funds from the American Rescue Plan Act.
In addition to the dam removal, the project also includes an impressive fishway constructed of concrete that diverts the herring around a particularly rocky section of the river, providing a smooth detour for part of their upstream jaunt. That spared energy is helpful, because once the herring exit the fishway, they still have to run the gauntlet of the river’s natural elevation rise.
And humans benefit from this project, too. The Armstrong dam was considered “high hazard” by the Massachusetts Department of Conservation and Recreation, meaning it carried risks to human life.
“You have a fairly large dam that if it were to fail, could cause quite a bit of damage. It’s in a highly developed, urbanized area,” said Chris Hirsch, dam removal manager for the Division of Ecological Restoration. This part of the Monatiquot is an oasis, but is sandwiched by two MBTA commuter rail lines, an RMV, multiple shopping centers and homes.
Old dams across Massachusetts
About 3,000 dams remain in the state. Hundreds are considered hazardous and many no longer serve a purpose. In January, Gov. Maura Healey’s administration announced half a million dollars would go to eight communities conducting preliminary studies for removals.
“Especially in the face of climate change — larger storm events, more frequent flooding — it’s really putting this infrastructure to its stress test,” Hirsch said.
With the dams gone, the natural flow of the Monatiquot River has returned in certain areas. Native grasses grow on the riverbank, sprouting from seeds that were submerged under the dam’s impounded water for two centuries. Braintree Mayor Erin Joyce said it’s a “beautiful” reminder of how removing old, forgotten dams can have ripple effects.
“Who knows what wildlife will be able to enjoy that space?” Joyce said.
Armstrong Dam Before and After
