This article was originally published in the Narragansett Bay Watershed Counts 2016 Report
From time immemorial, when dams were the intellectual property of beavers, alewife and blueback herring (collectively known as river herring) made their way from the ocean into Narragansett Bay and up the Saugatucket River each spring to lay eggs in upstream ponds. These eggs then hatched, and the juvenile fish swam back to the ocean to grow into adults before returning to the same birthplace, yet again, to spawn.
But, human innovation during the Industrial Revolution brought dams to the rivers to capitalize on flowing water for power. An unintended consequence was that these dams also blocked the fish migration corridors. For some time now, fish ladders have been installed at dam sites to help river herring navigate over the dams, but the fish sometimes reject or are unable to navigate these structures.
When Bill McWha moved to Wakefield, Rhode Island, in 2010, he noticed that the dam on the Saugatucket River prevented river herring from completing their journey from the ocean to the upper reaches of the Saugatucket to spawn. Once past the dam, blueback herring prefer to spawn in moving waters, such as streams and rivers, while alewife favor calm waters, such as ponds and lakes. If the fish can make it past the Wakefield dam, they have access to 20 acres of spawning habitat in Wakefield Pond. Although the Rhode Island Department of Environmental Management installed a fish ladder, the river herring were not using it to get around the dam, which remained a barrier. The natural cycle of migration and spawning was broken.
The river herring were prevented from reaching ideal spawning habitats with lower water temperatures, better river substrate, and slower water flows. Instead, the logjam of fish had no option but to spawn in less-than-ideal conditions at the base of the dam before returning to the sea.
“I could see that the fish couldn’t get past the dam using the fish ladder,” said McWha. “You couldn’t leave all those fish there and have them spawn at the base of the dam because once the eggs hatched, there would be too many young river herring and not enough food. They would starve to death, they’d eat themselves out of house and home.”
River herring are listed as a “species of concern” by the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service, in part due to the spawning issue. The concern is great enough that fishing for river herring is prohibited in Rhode Island and Massachusetts to protect plummeting populations. These fish are a crucial food source for a variety of animals, from eagles and ospreys to seals and striped bass, as well as being an important species for saltwater anglers and the associated tourist economy.
Fortunately, McWha decided to take action on behalf of the river herring, the striper, and the striper fishermen. He enlisted friends to catch river herring with nets and lift them over the dam. In 2010, McWha’s volunteers transported nearly 20,000 fish.
This annual event became something of a community calling. Volunteers returned each year to physically carry the fish over the Wakefield dam. Then, last year, the Rhode Island Department of Environmental Management reconstructed the fish ladder, and McWha and the volunteers happily stepped back to watch the river herring navigate past the dam unassisted. According to McWha, “It’s working well and volunteer services are no longer needed at that location.” However, river herring at other locations along the Saugatucket River need the volunteers’ help.
Just this past April, on a sunny Saturday morning, McWha and his crew of volunteers, the Saugatucket River Herring Association, were hard at work at the base of another problematic dam, the Palisades Mill in Peace Dale, one of some 667 dams in Rhode Island alone.
Lifting fish at the Peace Dale location required a more complicated operation than at the Wakefield dam— and more volunteers. A team used a “crowder fence” to herd the fish upstream towards the fish ladder entrance. Volunteers stood ready with nets to scoop up the fish and pass them onto the “bucket brigade,” a chain of volunteers who hauled the nets above the dam and released the fish into the stream to continue their journey.
“A lot of these volunteers are avid [striped bass] fishermen,” said volunteer Bob Cavanagh. “They’re doing this because they know it’s going to help preserve the striper population as well.”
“I’ve been involved every year,” adds volunteer Gerade Crute, a striper (striped bass) fisherman. “It’s rewarding, I love it.”
As the determined fish near their destination at Indian Lake, they face one last man-made challenge: small waterfalls created by the damming of the lake. But, McWha and volunteers were there once again to help the fish. They installed another ladder to assist the river herring to swim past the waterfalls.
Once past the dam at Palisades Mill, 45 acres of habitat opens up in Peace Dale Pond. If the river herring can make it all the way to the headwaters of the Saugatucket at Indian Lake, over 200 acres of pristine spawning habitat are available.
“The more habitat the better,” said Jim Turek, a restoration ecologist for the National Oceanic and Atmospheric Administration. “And if it’s good quality habitat that’s even better.”
According to Turek, Indian Lake’s size, shallowness, and clean, well-circulated water, devoid of the out-of-control aquatic plants in the two downstream ponds, make it an ideal spawning ground for alewife. This environment is conducive to higher dissolved oxygen levels, which help the fish to thrive.
“It’s a great place for the newly hatched juvenile fish to live for anywhere from three to six months before they go out to sea,” said Turek.
The Saugatucket River is not the only river where herring need a lift. On the nearby Pawcatuck River, recent dam removals established a herring run for first time in over a century. That run was aided by adding fish trucked over from the Saugatucket River to the Pawcatuck’s headwaters at Worden’s Pond.
In Massachusetts, the Hopewell Mills Dam was removed in 2012 on the Mill River, part of the Taunton River watershed. The Massachusetts Division of Marine Fisheries installed an underwater camera just upstream from the former dam.
“Within hours, the camera recorded the arrival of river herring, the first to be documented since the dam was built in the early 1800s,” said Beth Lambert, Aquatic Habitat Restoration Program Manager at the Massachusetts Division of Ecological Restoration.
“Every river on the whole East Coast had herring coming in, but we cut them all off with mill dams,” McWha said. “Many of these mill dams are obsolete and can be removed so river herring can resume their annual journey.”
McWha and volunteers recognized the important connection for river herring between the saltwater of the ocean, the mixed waters in the Narragansett Bay estuary, and the freshwater of rivers and streams, and they worked together to overcome barriers to river herring. Their efforts can bolster the river herring population and, in turn, promote a healthy ecosystem.
Freshwater eels in search of a home
River herring aren’t the only fish impeded by dams. The mill dam on the Pettaquamscutt River (also known as the Narrow River) adjacent to the Gilbert Stuart Birthplace and Museum in Saunderstown, Rhode Island, features an eel ramp adjacent to a fish ladder.
“Eels at this stage are very, very small,” said Kimberly Sullivan, Aquatic Resource Education Coordinator at the RIDEM Division of Fish and Wildlife. “They cannot jump up a fish ladder like the river herring, but they will slither up the eel ramp to reach the pond.”
American eels, called glass eels when they are very small, join the river herring in their upstream journey each spring—but for a very different purpose. Instead of returning to their birthplace to spawn, these young eels are searching for a place to live.
The eels are born in the North Atlantic Ocean and ride ocean currents into rivers and streams on the East Coast. They live out their lives in freshwater ponds before returning to the sea to spawn and die.
The Narragansett Bay watershed’s environmental health depends in part upon a careful assessment of old mill dams coupled with ongoing efforts to restore habitat critical to those species that travel from ocean to estuary to river pathways to the place they recognize as home.