A juvenile gray whale found washed ashore near the Alameda Creek Trail in Fremont's Coyote Hills Regional Park in September was apparently struck by a ship, according to necropsy results released by the Marine Mammal Center on Tuesday.
The 21-foot female whale was found on Sept. 24 with propeller strike injuries to its dorsal area. The injuries were consistent with reports of a ship hitting a whale in the Oakland outer harbor channel, center officials said.
But the injuries only penetrated the whale's outer blubber and did not cause any hemorrhaging or broken bones and may not have caused its death.
The whale was emaciated and had a spine abnormality that likely made it difficult for it to forage for food, according to the mammal center.
"Even if we are not able to determine a final cause of death, our research provides insights into the overall health of these animals and their ocean environment, including any human impacts that may play a role," Marine Mammal Center director of veterinary science Shawn Johnson said in a statement.
The whale was the eighth stranding the Marine Mammal Center has responded to this year. Of those, at least three appeared to have been hit by a ship and one died from entanglement with fishing gear.
To avoid whale deaths, the National Oceanic and Atmospheric Administration recommends that all vessels of 300 gross tons or larger in the area reduce their speed to a maximum of 10 knots per hour between May to November, when whales are gathering and feeding, according to the center.
In its 40-year history, the Marine Mammal Center has responded to a total of 67 stranded gray whales. They are one of the most commonly seen whales in California, migrating through coastal waters on an 11,000-mile journey between Alaska and Baja California.
Anyone who sees a sick or injured marine mammal has been asked to call the Marine Mammal Center at 415-389-SEAL.