First Alewife Spotted on the Hutchinson River Since the 19th Century

For the first time since the 19^th century, an alewife was recorded this spring in the Hutchinson River in southern Westchester near the Bronx border. That sighting is helping to validate an effort by environmental groups and state and county agencies to design a fish passage project on the river to return alewives to their historic spawning habitats.

The alewife was seen in March just below the Pelham Lake Dam in Mount Vernon, the first dam on the river, by Gareth Hougham, president of the Hudson Valley Arts and Sciences, one of the partner groups looking to design a fish passage project at the dam.    

Fish passage projects such as removing dams or building fishways over or around dams have proved to be a successful means throughout the US for migratory fish to overcome barriers to spawning habitat. Near the Hutchinson River, fishways have increased river miles for migratory fish in the Bronx River to the south and in the Mianus River in Greenwich to the north. In addition, despite pollution from the impacts of urbanization, the Hutchinson River has an abundance of wading birds preying on fish in the river. While these positive signs led to proposing a fish passage project for the Hutchinson River, evidence of a remnant population of alewives attempting to swim upstream of the Pelham Lake Dam still was missing.

Despite the hurdle of a global pandemic, project partners were determined this spring to monitor the Hutchinson River below the Dam to confirm the presence of migratory fish. On March 26, Hougham took two fish traps and placed them in the river below the dam. On March 27, Hougham checked the traps and found (along with some carp) one female alewife. This alewife confirmed that the Pelham Lake Dam does indeed block fish passage and migratory spawning alewife are still present in the river.

In 2018, Hougham’s organization, HVAS, applied for and received a tributary restoration and resilience grant from the New York State Department of Environmental Conservation to study the feasibility of fish passage for alewife at the Pelham Lake Dam. In partnership with Westchester County and with guidance from Save the Sound, NYSDEC, Queens College, and the Wildlife Conservation Society, the project is underway, and a contractor to design the fishway is expected to be selected soon.  

The Hutchinson River begins in Scarsdale and flows 10 miles south through southern Westchester County and the northeastern Bronx, emptying into Eastchester Bay and western Long Island Sound. The river has suffered from years of human alteration. Today, the impact on the river can still be seen from mouth to headwaters. The river contains Combined Sewer Overflows and is bordered by concrete plants, scrap yards, parkways, an Amtrak line, Co-Op City (the largest housing project in the world), and the Pelham Bay Landfill, which was closed in the 1970s.

One of the major impacts to the health of the river is the existing dams. At the end of the 19^th century into the early 1900s the New Rochelle Water Company dammed the river in several locations to create a reservoir system for the surrounding area. Although these reservoirs are now obsolete, the dams still exist creating impassable barriers for fish such as alewife. Alewives spend most of their lives in the ocean and only enter local freshwater tributaries in the spring to spawn. Once they spawn the adults return to the ocean and the juveniles grow up in the river throughout the summer. In the fall, the juveniles head to the ocean and, once mature, return in 3-5 years to spawn in their natal river. They are considered to be an integral part of freshwater and marine food webs, including as food for striped bass, osprey, cod, and trout.

Estuary programs in New York State, including the Long Island Sound Study and the Peconic Estuary Partnership, and the NYSDEC Hudson River Fisheries Unit, are working with partners to prioritize and evaluate the removal or modification of impediments to fish passage. If a successful design at Pelham Lake Dam, which is in Willson’s Woods Park, leads to a fish passage project, it will be the first in Westchester County in the Long Island Sound watershed. The program manager for NYSDEC is Vicky O’Neill, a NEIWPCC environmental analyst who is also the Long Island Sound Study Habitat Restoration and Stewardship coordinator in New York.