Herring are spawning in a tributary to New York's Hudson River for the first time in 85 years after a dam was removed from the tributary's mouth.

The spawning in the Wynants Kill tributary is seen as an environmental success, as NPR's Nathan Rott tells our Newscast unit. He says it was previously "closed off to fish by a 6-foot dam at the side of an old mill there." Nate explains:

"With the removal of the dam earlier this month, river herring and other ocean-going fish are making their way up the tributary to spawn. Those fish spend the bulk of their life at sea, but need smaller tributaries off of rivers like the Hudson to spawn and reproduce."

There are more than 1,500 dams affecting Hudson River tributaries and "there's a wider push to remove ones that no longer serve their intended purpose," Nate adds.

"Every dam should have an existential crisis," said John Waldman, a biology professor at Queens College, tells The Associated Press. "These are artifacts of the Industrial Revolution that are persisting and doing harm."

Riverkeeper, a watchdog organization aimed at protecting the Hudson River involved in the dam removal, describes Wynant's Kill as a "historic spawning run." They explain this is an effort to improve herring stocks which fallen for decades:

"Since the 1960s, river herring populations up and down the Atlantic Coast have significantly declined due to overharvest and the loss of spawning habitat. Federal and state biologists prioritize the restoration of this habitat as one of the best ways to encourage herring stocks to recover from current historic lows."

And herring are an "integral part of the aquatic food chain," as the Associated Press explains. "In the Atlantic, many species of fish, bird and mammal rely on herring as their primary food source," according to the wire service.

"Environmental improvement efforts like the removal of the Wynants Kill dam are critically important to maintaining a healthy Hudson River ecosystem," Mayor Patrick Madden said at a recent news conference, the Troy Record reports.

Riverkeeper's boat captain John Lipscomb sees this as one part of a broader Hudson River recovery:

"The construction of the Wynants Kill barrier almost 100 years ago cut off a tributary that was owned by the herring and other species. Now it's theirs again. That's how the Hudson River will recover. That's how the Hudson will be restored."

You can see the herring in action in this video from Riverkeeper:

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