April 6, 2026: Final Necropsy Results Show Chronic Diseases Contributed to Stranding
The entangled humpback whale that stranded near Yachats, Oregon, in November 2025 had several chronic diseases that likely contributed to the stranding. These are the results from the final necropsy report by the Oregon Veterinary Diagnostic Laboratory at the Gary R. Carlson, MD, College of Veterinary Medicine at Oregon State University.
“Significant chronic disease processes in multiple organ systems likely contributed to the stranding independent of entanglement,” the report said. The whale’s empty stomach and intestine also indicated that it likely had not eaten for weeks. That also left the whale with minimal fat stores, the necropsy found.
The laboratory’s examination of the male humpback whale found evidence of spinal cord disease likely caused by an infection, according to the report from Dr. Kurt Williams, director of the Laboratory and lead pathologist on the case. The whale’s intestine and colon had signs of severe widespread inflammatory disease, likely the result of intestinal parasites.
The whale, about 1 to 2 years old, also had evidence of chronic congestive heart failure as well as acute heart failure resulting from the stress related to the stranding. Responders would not have been aware of these underlying conditions when attempting a rescue.
“When I look at all the results in the context of what we know about the whale, there are many signs it was having problems long before the stranding,” he said. “My interpretation of events is that the animal’s pre-existing disease challenges contributed to the whale's entanglement and then to the live stranding.”
Williams reviewed the findings with marine mammal pathologists and scientists from around the world before finalizing the report. “We hope the findings from this case expand our understanding of whale diseases and spur future investigations to understand and improve the health of whales and the oceans around the globe,” the report said.
The Oregon Marine Mammal Stranding Network, coordinated by Oregon State University’s Marine Mammal Institute in Newport, Oregon, responded to the stranding in coordination with other partners. The Oregon program is part of the West Coast Marine Mammal Stranding Network and responds to strandings on the central and southern Oregon Coast.
November 19, 2025: Preliminary Necropsy Results
A large team from multiple organizations convened on Tuesday, November 18 to conduct a necropsy on the young humpback whale that stranded over the weekend.
The necropsy revealed the whale to be a male measuring 26 feet. The team collected many samples, which will undergo analysis at the Oregon State University Veterinary Diagnostic Lab. They noted some lesions. The whale had no stomach contents, and was in fair body condition at the time of necropsy.
The team is grateful to a local contractor that provided lighting and a small excavator. They are also thankful to the local community and bystanders for understanding the logistical and complex challenges that come with large whales onshore.
Oregon State University will release more details of the necropsy and the sample analysis as they become available.
On November 17, veterinarians from the West Coast Marine Mammal Stranding Network euthanized a young humpback whale stranded north of Yachats, Oregon, after an unsuccessful attempt to free it. The whale was entangled in gear when it first stranded on November 15. NOAA Fisheries attributed the gear to the 2023–2024 Oregon commercial Dungeness crab fishery.
Teams of trained responders from Portland and Seattle arrived November 16 and assessed the overall condition of the whale. They set up a rope and pulley system to try to free it from the beach at high tide the following morning. However, the attempt was unsuccessful.
While the whale remained alive, experts determined that euthanasia was the most humane option for this case. The prolonged period of time onshore had left the whale weak and unlikely to survive. Veterinarians euthanized the whale late afternoon on November 17. Responders will conduct a necropsy to assess the animal’s overall health and help determine why it stranded.
Why Attempts to Return Large Whales to the Ocean May Be Unsuccessful
A whale’s body is adapted to the buoyancy of water. Its own body weight causes immense pressure once it is stranded, which can lead to respiratory and circulatory collapse. Refloating stranded large whales is challenging, and there are limited options. Simply pulling a large whale back into the ocean is considered inhumane—it can dislocate the tail, cause paralysis, or even break the spinal cord. The rope and pulley system the Network members attempted is still difficult and not always successful. Another option, dredging a channel for a whale, has historically resulted in the whale drowning.
How to Help a Stranded Marine Mammal
Many people want to help stranded animals, but only trained responders should approach them. Even if a stranded animal is injured, attempting to touch or move them can be dangerous for you and the animal. We appreciate the many concerned onlookers who remained a safe distance from the whale, giving response teams room to work.
Responders conduct necropsies and collect samples to better understand the cause of death, which contributes to scientific research and future conservation efforts. Each stranding provides valuable data about the health of whale populations and the threats they face. To report a stranded or injured marine mammal, call (866) 767-6114.
We thank our partners in this effort:
- Pacific Marine Mammal Center
- SeaLife Response, Rehabilitation, & Research
- Cascadia Research Collective
- Oregon State Parks
- Oregon State Fish and Wildlife Department
- Oregon Coast Aquarium
- Oregon State Police
- Oregon State University’s Marine Mammal Institute
