A pod of dolphins just outside New York harbor. Carsten Brandt/Getty

Our thanks to Oliver Milman, Mother Jones and the Climate Desk collaboration for this, and we hope the frolicking continues:

To New Yorkers’ Delight, Dolphins Return to the Bronx River

“We’ve come a long way.”

Dolphins have been spotted frolicking in New York City’s Bronx River, an encouraging sign of the improving health of a waterway that was for many years befouled as a sewer for industrial waste.

A pair of dolphins was seen gliding through the river’s waters on Monday, the New York City parks department confirmed, near a small park in the city’s Bronx borough. The Bronx river rises north of New York City and cuts through the Bronx before terminating in the East River, the estuary that separates the Bronx and Manhattan from the boroughs of Queens and Brooklyn.

“It’s true—dolphins were spotted in the Bronx River this week!,” the parks department gleefully tweeted. “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.”

Dolphins have not been seen in the river for several years, but there has been an increase in sightings of the marine mammals in the waters around New York as the industrial pollution that blighted the region has eased.

Scientists previously set up underwater microphones at aquatic locations around New York to listen for the distinctive clicking noises emitted by bottlenose dolphins and found that they are particularly active in the harbor that separates New York and New Jersey. A pair of dolphins were seen in the waters off Brooklyn last year, surprising onlookers…

Read the whole story here.