Gray whale on Angel Island with missing fluke suffered 'slow and painful' death

Marine Mammal Center scientists performed a necropsy on a juvenile gray whale on Angel Island on Friday, March 30. Marine Mammal Center scientists performed a necropsy on a juvenile gray whale on Angel Island on Friday, March 30. Photo: Giancarlo Rulli/The Marine Mammal Center Photo: Giancarlo Rulli/The Marine Mammal Center Image 1 of / 28 Caption Close Gray whale on Angel Island with missing fluke suffered 'slow and painful' death 1 / 28 Back to Gallery

Scientists suspect a gray whale on Angel Island suffered a "slow and painful" death after a necropsy Friday revealed injuries consistent with severe entanglement and orca trauma.

Upon examination, officials from the Marine Mammal Center in Sausalito determined the deceased whale to be a juvenile female. The Coast Guard spotted the 26-foot carcass floating in Richardson Bay early Wednesday and alerted the center, which tugged the carcass to Angel Island State Park with assistance from the Army Corps of Engineers.

Center scientists returned to the island Friday and discovered the animal's fluke was missing and completely severed, the organization said Tuesday in a press release. They found copper wiring strands wrapped in plastic embedded in the necrotic tail stump – "consistent with entanglement residue" – and numerous rake marks and rib fractures, likely due to an orca attack.

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The Center cited "severe entanglement" and "orca trauma" as the primary factors contributing to the young cetacean's death.

"This whale endured an extremely slow and painful decline due to multiple contributing factors," said Christine Fontaine, senior research assistant at the Marine Mammal Center, in a statement. "Although it's not known whether the animal contracted the entanglement prior to the suspected orca predation, the samples taken today provides baseline data so that we can try to better understand this animal's lifecycle."

Further analysis of the animal's blubber, organs, baleen and tissue will be conducted in the future.

The juvenile is the second whale the center has responded to this year. In March, the organization and the California Academy of Sciences responded to a deceased juvenile gray whale on Angel Island. The cause of death remains undetermined.

READ MORE: 28-foot-long dead gray whale washes up on Angel Island beach

The most common contributors to cetaceans deaths, according to the center, include blunt force from ship strikes, malnutrition and entanglements.

Gray whales frequent California's waters between the winter months of December and January, as well as April and May, as they migrate to and from their breeding grounds in Mexico.