NYC Parks, in partnership with the Bronx River Alliance, Bronx Zoo/Wildlife Conservation Society, and the New York State Department of Environmental Conservation (NYSDEC) today came together to stock the Bronx River with 250 alewife, a type of river herring.

“Despite the ongoing pandemic, we are thrilled to have been able to take part in this year’s “running of the fish,” an important part of our efforts to increase biodiversity and restore ecological value to the Bronx river,” said NYC Parks Commissioner Mitchell J. Silver, FAICP. “We are proud to work closely with the Bronx River Alliance, the Bronx Zoo/WCS, and the NYSDEC to make this year’s alewife restocking a reality.”

"After missing last year's fish release due to travel restrictions caused by the COVID-19 pandemic, we are so excited to work with our partners to introduce 250 river herring into the Bronx River. 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,” said Maggie Greenfield, Bronx River Alliance Executive Director.

NYSDEC Commissioner Basil Seggos said: “Whether it’s the recent stocking of 1.8 million trout in New York State waters or partnering with NYC Parks to stock alewife in the Bronx River, DEC is committed to achieving our fish production objectives and increase fish diversity across the state. DEC is pleased to work with NYC Parks and the Bronx Zoo/WCS to help re-establish species like alewife in the Bronx River.”

In its 5th year, the “running of the fish,” hopes to continue combatting the steady decline of alewife populations in the northeast. Pollution, overfishing, mismanagement of fisheries and impediments to migration have all played a role in reducing the population of alewife. Historically, the river herring “run” or migration upstream to spawn each April is a symbol that spring has arrived.

The restocking is part of an ongoing effort to re-establish a population of these native fish in one of the nation’s most urbanized waterways. This year, NYSDEC trapped and transported the fish from the Peconic River in Long Island to the Bronx River.

This year, scientists from WCS and the City University of New York (CUNY) will also be using new tools to monitor alewife in the Bronx River. Through measurement of environmental DNA (eDNA, molecules left behind in the water by fish) in water samples collected from the river, they will be able to track the presence of alewives through the spawning season. An underwater remote operated vehicle (ROV) is also used to corroborate the eDNA findings with visual surveys and environmental conditions.

“The partnership between the Bronx Zoo/WCS, NYC Parks, Bronx River Alliance, and the NY State DEC has been enormously beneficial to the restoration of the Bronx River,” said Merry Camhi, Director of WCS New York Seascape Program. “Through the use of these new tools, WCS and CUNY hope to increase our ability to monitor and gauge the success of this ongoing fish restoration project and apply the technology to discover relict runs of alewife in other rivers and streams in the region.”

River herring are anadromous fish; meaning they live in the ocean but spawn in freshwater. Alewife are river herring that are native to this region. These fish are an important food source for larger fish, birds and other wildlife in our ocean, estuaries and rivers. Restoring passage to the Bronx River will provide additional habitat and increase local biodiversity.

In 2015, NYC Parks constructed a fish ladder over the 182nd Dam to allow fish to migrate upstream to spawn. This ladder gives fish access to 12 acres of freshwater habitat that have been blocked for centuries and allows them to pass from river to ocean.