A 28-foot juvenile male gray whale that washed up on a remote Angel Island beach likely died of malnutrition, according to the Marine Mammal Center.
Eight scientists from the mammal center, California Academy of Sciences and University of California at Davis went to Sand Springs Beach on the southeast portion of the island to perform a necropsy on the stranded whale carcass.
Early in the necropsy on Thursday, scientists discovered a significant lack of muscle tissue and blubber, a sign of atrophy. Scientists noted the animal also had a minimal amount of food in its stomach, an indication the whale had not eaten recently. Based on the lack of overall trauma to the animal, severe malnutrition is the suspected cause of death.
“Every whale stranding is an incredible opportunity to learn from these amazing animals and contribute to baseline data,” said Dr. Padraig Duignan, chief research pathologist at the mammal center. “This particular gray whale was likely in its first year of foraging on its own in the wild, and it’s unknown whether this juvenile was following a food source into San Francisco Bay prior to its death.”
Mammal center personnel collected tissue samples to contribute to various research studies and the California Academy of Sciences archived pelvic bones and a rib collection.
“The beach is very remote, so we will leave it to naturally decompose,” said Giancarlo Rulli, spokesman for the center. “It tends to break down very rapidly and provides a source of nutrition for bird and crabs along the shore.”
The center’s rescue department first received reports Wednesday morning from the U.S. Army Corps of Engineers of the dead cetacean floating in the current between Angel Island and Belvedere.
The center has previously responded to more than 70 gray whales in its 43-year history. In May 2007, the center and its partners responded to a mother and calf pair of humpback whales dubbed Delta and Dawn that entered San Francisco Bay. The whale pair swam up the Sacramento-San Joaquin River Delta before rescue crews were able to coax the animals back to the Pacific Ocean.
This is the first whale the center and its partners at the California Academy of Sciences have responded to this year. While “undetermined” is the most common cause of death of cetaceans reported by the center’s necropsy team, blunt force trauma from ship strikes, malnutrition, trauma and entanglements are other leading causes, officials said.