Dolphins seen swimming in New York City's Bronx River

Sighting creates boon for efforts to protect and restore river in northern city borough

The East River between the Queens and Bronx boroughs in New York City. AFP

Environmental groups said on Thursday that they had seen dolphins frolicking in one of New York City's rivers.

"It’s true. Dolphins were spotted in the Bronx River this week," the New York City Parks Department exclaimed in a tweet.

"This is great news. It shows that the decades-long effort to restore the river as a healthy habitat is working.

"We believe these dolphins naturally found their way to the river in search of fish."

The Bronx River Alliance is an organisation of conservation groups working to restore and protect the river that streams through the centre of the northern-most New York City borough and flows into the East River.

The alliance wants to increase the river's well-being for the community and help to improve it as a natural habitat, making the sighting of dolphin pods welcome news.

The city's Parks Department said it regularly restocks the Bronx River with alewife and other fish so natural wildlife such as dolphins would not go without food.

The department advised New Yorkers to give dolphins space and not to disturb them.

The Gothamist said dolphins were also seen in the Greenpoint neighbourhood in northern Brooklyn, marking a potential trend.

The New Scientist magazine said dolphins were found in the East River in 2021.

"Cancelling my entire schedule tomorrow to go dolphin sighting in the district. Pull up," New York State Assembly member Kenny Burgos tweeted.