A wayward dolphin which meandered into a polluted urban canal in New York, riveting onlookers as it splashed around in the filthy water, has died.
The deep-freeze weather did not seem to worry the dolphin as it swam in the Gowanus Canal, which runs 1.5 miles through a narrow industrial zone near some of Brooklyn's wealthiest neighbourhoods.
Marine experts had hoped high tide would help the dolphin leave the canal safely. But the dolphin was confirmed dead shortly before then, said the Riverhead Foundation for Marine Research and Preservation.
Earlier, with the dolphin swimming about and surfacing periodically, onlookers took photos using their phone photos, and a news helicopter hovered overhead.
The New York Police Department said the foundation's experts had planned to help the dolphin if it did not get out of the canal during high tide. The foundation, based in Riverhead, on eastern Long Island, specialises in cases involving whales, dolphins, seals and sea turtles.
The filthy canal was named a Superfund site in 2010, meaning the government can force polluters to pay for its restoration.
For more than a century before, coal yards, chemical factories and fuel refineries on the canal's banks discharged everything from tar to purple ink into the water, earning it the local nickname The Lavender Lake for its unnatural colour.
The dolphin, which appeared to be about 7ft long, probably entered the canal from the Atlantic Ocean through the Lower and Upper New York Bays and then the Gowanus Bay, which leads to the canal. It is about 20 miles from the canal to open ocean.
It is not the first sea creature to venture into New York City waters with fatal consequences. A dolphin was found dead last August near Long Island, south of the canal, while another washed up in June in the Hudson River near Manhattan's Chelsea Piers sports complex.
In 2007, a baby minke whale that briefly captivated the city wandered into the Gowanus Bay and swam aimlessly before dying. But two years later, a 20ft humpback whale took a tour of the city's waters before leaving New York Harbour safely.