NEW YORK (AP) — Marine experts say a dolphin seen shaking black gunk from its snout after wandering into a polluted canal in New York may well have been ill before it lost its way and died.

The wayward dolphin splashed around in the filthy waters of the Gowanus Canal before it died Friday. The canal is a Superfund site, where for years factories and fuel refineries operated. It runs through an industrial zone near some of Brooklyn's wealthiest neighborhoods.

Marine experts had planned to help the dolphin on Saturday morning if it didn't get out of the canal during high tide. They had decided to hold off intervening Friday because of the stress the dolphin might have experienced in being captured.

Experts plan to conduct a necropsy to determine why the dolphin died.