Robert Schoelkopf of the Marine Mammal Stranding Center in Brigantine said the whale on the beach in Ocean City appears to be an immature finback, The Press of Atlantic City reported. He said in photographs it appears to be 40 to 45 feet long, while a full-grown finback can reach 70 feet.
The whale rolling in the surf attracted a small crowd to Seventh Street Beach on Monday afternoon.
Ryan Day of Ocean City works on a party boat that does sports fishing trips off the Jersey Shore.
"I've never seen a dead whale before," Day said. "I've been on the water all my life, and this is neat to see. We see them all the time alive out there."
By late afternoon, the whale still had not beached. Schoelkopf said it would be difficult to tie it down and do a detailed examination until it came ashore.
He said a similar dead whale, spotted a week ago near Ambrose Light, had probably been carried by currents to Ocean City. Given the number of vessels entering and leaving New York Harbor, the whale may have been the victim of a ship strike, Schoelkopf said.
Finbacks, or fin whales, are an endangered species.