The Bronx River was stocked with 250 alewives from the Peconic last week. Photo: Julie Larsen Maher/Wildlife Conservation Society

New York City residents may be flocking to the East End in the age of the coronavirus, but a select group of locals has moved en masse to New York City.

Alewives, that is.

The silvery herring make an annual early spring run from the waters of the northern Atlantic into the freshwater habitats of the Peconic River to breed. This year about 250 of the fish were netted by DEC fisheries staff and transported to the Bronx River, where they were released as part of an effort to restore the alewife in New York City’s only freshwater river.

This is the fifth year for the restocking of the Bronx River with the herring — but the first time fish from the Peconic made the journey. The project is a partnership of the New York State DEC, the New York City Parks Department, the Wildlife Conservation Society — which operates four New York City zoos and the New York Aquarium — and the Bronx River Alliance.

The annual alewife run brings more than 50,000 herring into Peconic Lake, said Byron Young, a retired NY State DEC fisheries biologist who has personally worked to help the alewives have a safe passage to their spawning grounds since the 1990s.

Man-made obstructions, such as dams and spillways, impede the migration of the small river herring to safe waters where they breed. Beginning in 1995, Young began working alongside Bob Conklin, a Riverhead Middle School science teacher, to help the alewives complete their annual journey, moving the fish over the dams and spillways to the 60-acre pond in the Peconic River every spring,

In 2000, an aluminum fish ladder was installed to help the migration. It had to be put in place and removed each season.

2012 0909 fishway
The fishway in Grangebel Park. Photo: Peter Blasl

A permanent fishway was completed in 2010 as part of a waterfront improvement project in Grangebel Park. Though Conklin did not live to see it completed, the fishway was dedicated to him on April 12, 2010, in honor of his passion for ensuring the safe passage of alewives to their spawning grounds. The project, a joint effort of Riverhead Town, the U.S. Environmental Protection Agency and the State DEC, received a national award from Coastal America in 2011.

“The run has improved significantly since we put the fishway in Grangebel,” Young said in an interview today. Marine scientists use underwater video cameras to track the annual “running of the fish” and estimate the total number, he said.

This time of year, you can find the retired fisheries expert at the Woodhull dam in the Peconic River, manually scooping up alewives and moving them over the dam. Young was on hand last Thursday morning when the Bronx-bound alewives were netted and placed in a tank on a truck for the trip to the Bronx.

“The return of the alewife herring to the Bronx River represents such an important milestone for the restoration of the Bronx River, and we are proud to be a part of this annual event,” Bronx River Alliance executive director Maggie Greenfield said.

The alewife is an important part of the river’s ecosystem. It is a major food source for bluefish and striped bass, schools of which will often follow the returning alewives for many miles up estuaries and rivers, according to the Bronx River Alliance. The alewife is also eaten by herons, ospreys, cormorants, and even bald eagles – and they’re healthier for them, too, since they return from the ocean with fewer toxins in their bodies than most freshwater fishes. They also feed eels, gulls, raccoons, crayfish, and turtles, and as the only known host for the freshwater mussel known as the “alewife floater,” the alewife may help reestablish this native population of filter feeders that will help clean the water.

Ranging from Newfoundland to South Carolina, the alewife is spawned in fresh or brackish water, after which both juveniles and adults return to the ocean, where they make their way up the coast. The adults repeat the journey the following spring, but the juveniles remain up north for about five years, then they return to the very waters in which they themselves were spawned in to begin a new round of their life cycle. A single alewife may do this for as many as seven or eight years in succession.

After the construction of the first mill dams in the Bronx River in the 1680s, the alewives disappeared from the river. The Bronx River Alliance is working to re-establish the spawning grounds and to build fish passages to enable the alewives to navigate their way past the dams to the fresh still waters upstream.

Safe passage for the alewives to their spawning grounds in the Peconic is not yet complete and still relies on intervention from dedicated naturalists like Young, who works to move the fish over the Woodhull dam.

Young said plans are now underway for a new fishway at Woodhull dam in the Peconic, to provide safe passage for alewives on the last leg of their journey to their spawning grounds..

Recreational harvesting of river herring is prohibited in marine waters south of the George Washington Bridge, according to the State DEC.

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Denise Civiletti
Denise is a veteran local reporter, editor, attorney and former Riverhead Town councilwoman. Her work has been recognized with numerous awards, including investigative reporting and writer of the year awards from the N.Y. Press Association. She is a founder, owner and co-publisher of this website.Email Denise.