SAN FRANCISCO — A whale that washed up dead on Ocean Beach on Monday had several fractures to its skull and other injuries to indicate it was hit by a ship, officials for The Marine Mammal Center said.

Scientists performed a necropsy — an animal autopsy — on the beach Tuesday and said blunt force trauma associated with its collision with a ship caused the death.

The whale is the ninth to be found dead this year in Bay Area waters, and the fourth that has been hit by a ship, officials said.

Dr. Padraig Duignan, the Chief Research Pathologist at the mammal center said scientists are “incredibly concerned” about the pattern.

The necropsy showed that several vertebrae on the 41-foot whale also were broken, and that it has suffered significant bleeding and bruising, officials said. The whale was female and also appeared to be a bit malnourished, with a layer of blubber that was thinner than normal, officials said.

The whales migrate from Alaska to Baja, California and back each year, the longest migration in the world, according to the mammal center.

“As gray whale migration season enters its final stages of the season, adult female gray whales and their calves with low body reserves are the last to migrate northward to their feeding grounds in the Arctic,” Duignan said in a statement. “These mother whales are worn out and running on empty, making them even more susceptible to negative human interactions, including ship strikes and entanglements.”

Two whales found dead along the waterfronts of San Mateo and Richmond found three days apart in April both were hit by ships, officials said. A ship also fatally hit a whale that washed up in Pacifica on April 16.

Officials at Golden Gate National Recreation Area were working on a plan to remove the whale’s body, officials said. Members of the public and their pets were advised to stay away.