A dolphin has died in a polluted New York canal, despite efforts to save it

The disorientated mammal was spotted yesterday in the shallow waters of Brooklyn's Gowanus Canal.

But it died later in the day.

Witnesses said the dolphin struggled with the canal's muddy floor.

Biologists had been monitoring the animal, in the hope it would swim out at high tide.

Local media say the dolphin will be examined to determine a cause of death.