A rescue worker tries to keep this fin whale alive by dumping water on it after it beached itself yesterday in Breezy Point, Queens.

The 60-foot mammal finally floated off last night when the tide rose and was last seen spouting in Jamaica Bay. But its prognosis wasn’t good.

“The whale’s been sick for a long period of time,’’ said Kimberly Durham, of the Riverhead Foundation for Marine Research.