Written By
Some fish live in two worlds, migrating back and forth between the marine environment and freshwater rivers, streams, lakes and ponds each year to complete their life cycles.
Blueback herring and alewife, known collectively as river herring, are just two of nearly a dozen migratory fish species native to the eastern United States that make these annual journeys between salt and fresh water. But river herring are good representatives for this school of others with similar needs and challenges. Like what?
As if swimming thousands of miles each year through ocean currents and past predators wasn’t hard enough, these fish have had to navigate water pollution, dams blocking migration, and overfishing.
Those stressors took a toll on river herring populations and on communities that benefited from these fish.
From massive runs to moratoriums
A few centuries ago, hundreds of millions of river herring surged up coastal rivers each spring � turning the water silver with their gleaming scales, according to historical accounts.
These massive runs supported ways of life. River herring are significant to many Native American Tribes both as sustenance and symbols of spring’s return. Colonial settlers in coastal communities also came to rely on these fish. According to the Rhode Island Department of Environmental Management, “herring were once collected in large dip nets by the barrel, and used for pickling, smoking, canning, and even fertilizer.�
As prey for many bigger fish, river herring fueled commercial fisheries in the 20th century and came to be prized by recreational fishers for bait.
But records suggest that as early as the 1700s, populations were starting to decline due to overharvest and construction of dams that blocked the fish migrations to crucial spawning areas.
Things got worse. Commercial harvest peaked in the late 1950s at nearly 75 million pounds and then began to plummet. A decade later, annual landings had halved. In the 1970s, they dipped below 10 million pounds.
Today, most Northeast states have moratoriums on harvesting river herring, and both blueback herring and alewife have been classified as Species of Greatest Conservation Need in states across their ranges.
Different strokes
While river herring up and down the Eastern Seaboard face a similar plight, different populations have unique challenges � and opportunities. A 2024 stock assessment by the Atlantic States Marine Fisheries Commission concluded that river herring are still depleted on a coastwide basis. But the report also noted reasons for hope. In the Gulf of Maine, the stocks are showing signs of improvement.
To enhance and restore populations with distinct needs, the U.S. Fish and Wildlife Service coordinates with partners in different parts of the region � the Gulf of Maine, southern New England and mid-Atlantic � to tailor the response for maximum impact. Depending on the situation, they could focus on removing barriers, providing fish passage fish passage
Fish passage is the ability of fish or other aquatic species to move freely throughout their life to find food, reproduce, and complete their natural migration cycles. Millions of barriers to fish passage across the country are fragmenting habitat and leading to species declines. The U.S. Fish and Wildlife Service's National Fish Passage Program is working to reconnect watersheds to benefit both wildlife and people.
Learn more about fish passage , restoring habitat, or prohibiting catch if populations are low.
Population monitoring, assessment and research are critical activities tied to these restoration efforts too. State and federal agencies also work together on hydropower relicensing to provide new or improved passage and passage protections.
This strategic approach has positive ripple effects. For example, removing obsolete dams and upgrading road-stream crossings reconnects waterways for many aquatic species and also benefits local communities by reducing flooding risks and safety hazards associated with aging infrastructure. Restoring habitat helps other species, improves water quality, and benefits the whole ecosystem. Reducing catch of river herring to boost their populations supports sustainable fisheries.
So, what makes a good project? Here is a snapshot of three successful projects that addressed needs in different parts of the species range:
Gulf of Maine
Status of the stock
The status of river herring in the Gulf of Maine has been changing for the better in recent years, due to both improved water quality and improved fish passage resulting from dam removals and installation of modern fish-passage infrastructure along with trap and transfer projects. Many of these projects have been supported by the Service in collaboration with federal and state agencies, Tribal partners, conservation organizations and local communities.
Project highlight: Reconnecting the China Lake outlet stream in Maine
Project partners: Maine Rivers, The Nature Conservancy, the Maine Department of Marine Resources, the USDA Natural Resources Conservation Service, and the Service
What they did: Between 2017 and 2021, the partners collaborated to remove or modify six dams on this tributary to the Sebasticook River, allowing river herring to migrate from the Kennebec River to China Lake for the first time in 220 years.
Results:
- Opening access to 4,000-acre China Lake increased alewife spawning habitat in the Sebasticook River watershed by 50%. The seven-mile outlet stream added 20% more blueback herring spawning habitat.
- More river herring means more harvested lobsters. Lobstermen bait their traps with these fish when other sources are scarce and expensive.
- The presence of alewives has also improved China Lake’s water quality, benefiting residents and recreationists, as well as those whose municipal water supply comes from the lake.
Read the full story: The little stream that could, and will again
Southern New England
Status of the stock
Alewife and river herring runs continue to fluctuate widely in southern New England, despite investments in fish passage and habitat improvement comparable to those in Maine. Fisheries remain closed in all three southern New England states: Massachusetts, Rhode Island and Connecticut. As in other areas, population monitoring, assessment and research are critical to progress � helping us understand how populations respond to passage, identify passage needs, and determine limiting factors.
Bycatch � when commercial fishing operations catch nontarget fish � is likely one factor. In its 2024 stock assessment, the Atlantic States Marine Fisheries Commission documented river herring bycatch in ocean fisheries in southern New England in the winter and early spring � the time of year when these fish are migrating back to freshwater. In response, the New England Fishery Management Council is considering measures to monitor and reduce bycatch off the coast, following successful initiatives that have been implemented in Maine.
Project highlight: Dam removals in the Taunton River watershed in Massachusetts
Project partners: City of Taunton, Massachusetts Division of Ecological Restoration and Division of Marine Fisheries, the National Oceanic and Atmospheric Administration, The Nature Conservancy, Acuity Management, and the Service
What they did: Between 2012 and 2018, partners removed three dams on the Mill River in the Taunton River watershed of Massachusetts � Hopewell Mills, Whittendon, and West Britannia � and installed a fishway on the Morey’s Bridge Dam, at the outlet of Lake Sabbatia.
Results:
- With the removal of the West Britannia Dam, the Mill River is now open from the Taunton River � the longest undammed coastal river in New England � to Lake Sabbatia. A fishway provides access to the lake and habitat farther upstream
- River herring and other fish can now access more than 30 miles of streams and 400 acres of lakes and ponds.
- Without aging dams blocking natural flow, the Mill River is more likely to stay within its banks and floodplains during rainstorms.
Read the full story: Of herring and humans
Mid-Atlantic
Status of the stock
River herring numbers in the mid-Atlantic have generally stayed the same, or increased slightly, since a benchmark assessment by the Atlantic States Marine Fisheries Commission in 2009 showed dramatic declines. Both commercial and recreational harvests of river herring have been banned in mid-Atlantic rivers from New Jersey to Virginia since 2012. Restoration efforts, many supported by the Service, have focused on removing dams, installing fish passage and stocking in some locations.
Project highlight: Dam removals on Maryland’s Patapsco River
Project partners: Maryland Department of Natural Resources, Maryland Biological Stream Survey, Maryland Geological Survey, U.S. Geological Survey, National Oceanic and Atmospheric Administration, the Friends of the Patapsco Valley State Park, the University of Maryland Baltimore County, American Rivers, the Smithsonian Environmental Research Center, and the Service
What they did: In 2018, partners removed the Bloede Dam on the Patapsco River, which drains to Chesapeake Bay, with support from the Disaster Relief Appropriations Act of 2013.
Results:
- The removal of the Bloede Dam addressed an immediate public safety need at Patapsco Valley State Park � the dam had been the site of numerous injuries and deaths over the years.
- The project also opened 65 miles of spawning habitat for blueback herring, alewife, American shad, and hickory shad.
In 2021, Maryland Department of Natural Resources documented herring upstream of the site of the Bloede Dam for the first time in more than a century.
Read the full story: Bloede Dam removal complete: Patapsco River surges back to life
Fish passage projects near you
These are just some of the projects undertaken in the region to enhance and restore aquatic habitats for people and wildlife.
Since 2009, the Service has worked with state and federal agencies, Tribes, conservation organizations and communities to remove 940 barriers to fish passage in the Northeast alone, restoring access to nearly 9,000 miles of river and stream habitat and 80,000 acres of lakes, ponds and wetlands.
Want to learn about fish-passage projects happening near you? Use our web mapper to .
