On Sunday, April 11, 2010, staff from the Bronx River Alliance and Queens College netted a 255 mm male alewife on the Bronx River. The capture marks the second year in a row that this species of fish has been observed in the river since the species was reintroduced in four years ago.
“Finding alewife in the river again this spring is evidence of the reintroduction program’s success and a testament to the improvements made by ongoing restoration efforts along the Bronx River,” said Linda Cox, Bronx River Alliance Executive Director/NYC Parks Bronx River Administrator.
Like salmon, alewives (Alosa pseudoharengus) are anadromous fish, meaning they are born in fresh water, migrate to the ocean for their adult life and return to the place where they were born to spawn. Experts believe that alewives were once abundant in all tributaries entering Long Island Sound, including the Bronx River, but that dam construction starting in the 1600’s likely prevented their yearly migration back to the freshwater reaches of the river. In 2006, the U.S. National Marine Fisheries Service declared alewife and blueback herring, collectively known as river herring, as “species of concern.” Both are considered an important part of the energy and food chain in a healthy river ecosystem and are a critical part of the diet of birds, mammals, and large sport fish in streams, estuaries and the ocean.
In 2006 and 2007, the New York City Department of Parks & Recreation Natural Resources Group (NRG) and the Connecticut Department of Environmental Conservation reintroduced alewife into the river, in partnership with the Bronx Zoo, and in April 2009, the first alewife was netted as it migrated upstream to spawn. Under the direction of NRG, the Bronx River Alliance, and other partner organizations installed a trap in River Park near 180th St. in the Bronx on April 1, 2010, to determine the presence of alewife heading to spawn this year. Now that one has been caught, the trap will be removed, to minimize mortality to other returning fish.
The presence of alewives, together with the appearance of Jose the beaver in 2006, speaks to the remarkable ability of a heavily urbanized waterway to support a diversity of life. It also testifies to the resurgence in the overall health of the river that has occurred as a result of work by community members, local non-profits, and government agencies. The return of the alewife is an example of the positive benefits that occur when this partnership mobilizes.
“These alewives make an extraordinary journey from Nova Scotia, after which they pass combined sewer outfalls, garbage booms, active shoreline construction and a confined culvert on the Bronx River to reach the base of the 182nd St dam.” said Marit Larson, Deputy Director of Wetland and Riparian Restoration at NRG. “Our next step is to assure they have passage over this dam to enable them to reach suitable spawning habitat. NRG and the Bronx River Alliance are continuing to work with the Bronx Zoo, the New York Botanical Garden, with support from the National Oceanic and Atmospheric Administration, the National Fish and Wildlife Foundation, and the New York State Department of State, to plan the construction of fish ladders at all three dams in the Bronx. This will open the upper reaches of the river as spawning grounds for even more returning alewife.“
Photo by George Jackman.