Sturgeon are an endangered species. In the fall, females lay eggs in the rivers of the Chesapeake Bay, and then migrate offshore, said Noelle Mathies, a marine biologist, who specializes in sturgeon research.

The adult Atlantic sturgeon that washed up on the beach was about 5 feet long. Its five rows of bony plates, called scutes, were still mostly intact, but its head was nearly detached.

“It’s rare to get a fresh one,” Mathies said.