[SCROLL DOWN FOR UPDATES]
Gothamist reports the dolphin, first spotted Friday morning near Union Street in Brooklyn, appears to be tangled in an unidentified object.
Police and ambulances are at the scene.
A witness, Rebecca Rogers-Hawson, described, "It was probably injured or sick, I don't know why it would want to come in here."
NBC reports the animal is "bobbing up and down in the murky water, the spout in its head visible each time it pushed itself above the surface."
The Gowanus Canal, of course, is highly-polluted. The EPA estimates it will cost a staggering $500 million to clean up the Superfund site.
Update: NYPD spokesman Paul Browne said, "At [the Riverhead Foundation's] recommendation, we are waiting for the next high tide at 7:10 p.m. to see if the dolphin can free itself."
Update: The New York Daily News reports the dolphin has died.