Attempts to free a humpback whale grounded on a sandbar in Moriches Bay were unsuccessful, according to the Riverhead Foundation for Marine Research and Preservation.

The whale was seen stuck in Hart Cove off East Moriches on Sunday. Riverhead Foundation biologists went out in boats to monitor the animal’s condition and create waves in an effort to move it. The effort, done with the support of the Southampton Town Bay Constable and the New York State Department of Environmental Conservation, was unsuccessful and the Riverhead Foundation is now consulting with NOAA Fisheries to determine the best course of action.

advertisement | advertise on newsday

Mike Busch, 50, of Brookhaven, said he saw the stranded whale early Monday morning.

“It’s not really moving, other than occasionally raising its fluke out of the water to scare the seagulls off its back,” Busch said.

The whale was seen swimming in the bay last week “exhibiting behaviors that are consistent with feeding,” the Riverhead Foundation said. While it is unusual to see humpback whales in Moriches Bay, it is common to see them off the south shore of Long Island.

The Riverhead Foundation warns that the size of the whale, which is estimated to be 25-feet long and between 15 to 20 tons, and its “current stressed condition” make it “very dangerous” and the public should not go near it. Federal law states that the public should safely observe wild marine animals from a distance of at least 150 feet away.