HPAI H5N1 Confirmed in Northern Elephant Seals at Año Nuevo; Park Viewing Areas Closed as Coastal Surveillance Expands
Seven weaned northern elephant seal pups at Año Nuevo State Park tested positive for highly pathogenic avian influenza HPAI H5N1, prompting park viewing closures, expanded coastal surveillance and public warnings to avoid contact with seals and wild birds.
Key takeaways
- Seven weaned northern elephant seal pups at Año Nuevo tested positive for HPAI H5N1; initial reporting and testing were led by UC Davis and state park authorities (California Department of Parks and Recreation).
- Sick animals exhibited respiratory and neurological signs — weakness, tremors and seizures — and some pups died, according to field reports (UC Santa Cruz reporting via Mongabay).
- Samples were initially screened at UC Davis’ lab and confirmed as HPAI H5N1 by the USDA’s National Veterinary Services Laboratory; surveillance has expanded along the coast with ~30 more tests pending (RSOE EDIS).
- California State Parks closed public seal viewing areas and canceled guided elephant seal tours for the season while investigations continue (news release).
Outbreak timeline and testing
Feb. 19–20, 2026: Researchers monitoring the Año Nuevo Reserve observed unusual illness among elephant seals, including abnormal breathing and neurological signs such as weakness, tremors and seizures. Several pups were found dead or dying, prompting immediate sample collection.
Samples from sick and dead seals were sent to the California Animal Health and Food Safety Laboratory System at UC Davis for initial screening. Subsequent confirmatory testing by the USDA National Veterinary Services Laboratory (NVSL) identified the virus as highly pathogenic avian influenza H5N1. Tests on roughly 30 additional animals were reported as pending (RSOE EDIS).
Año Nuevo colony and surveillance partners
Año Nuevo State Park, inside the Monterey Bay National Marine Sanctuary north of Santa Cruz in San Mateo County, hosts about 5,000 northern elephant seals during the winter season; approximately 1,350 were on the beach when the event began. Long-term monitoring by UC Santa Cruz researchers — a six-decade record of individually identifiable seals — allowed teams to detect illness quickly (Mongabay / UC Santa Cruz reporting).
The scientific and response effort has been multiagency: UC Davis, UC Santa Cruz, NOAA Fisheries, the California Department of Fish and Wildlife and the West Coast Marine Mammal Stranding Network are coordinating monitoring, testing and response (The Marine Mammal Center).
Response measures and public warnings
California State Parks closed public access to seal viewing areas and canceled guided elephant seal tours beginning Feb. 23 as a precaution while the investigation continues (official news release).
Surveillance efforts have been expanded from Sonoma County down to San Luis Obispo County, with monitoring of nearby beaches in San Mateo and Santa Cruz counties. Officials reported that early detection likely limited spread; experts praised the rapid, coordinated surveillance that identified the cluster quickly (Mongabay).
“Exceptionally rapid detection” — Christine Johnson, UC Davis Institute for Pandemic Insights, on coordinated surveillance and early response.
Context — why this matters now
HPAI H5N1 has circulated globally since 2020 and has caused large die-offs among pinnipeds and sea lions in South America. Notable events include mass mortalities at Argentina’s Península Valdés and widespread sea lion deaths across South America in 2022–2024, motivating increased marine surveillance in North America (reporting).
By December 2025 the U.N. reported infections in hundreds of bird and mammal species worldwide — underscoring the pathogen’s reach. The Año Nuevo detections mark the first confirmed HPAI H5N1 cases in northern elephant seals and the first detection in any marine mammals in California (CIDRAP).
Public health and safety guidance
Risk to the general public is described as very low. There is no evidence of seal-to-human transmission from this event so far, but because HPAI can sometimes infect people, agencies urge caution (A Flu Diary / California DPH advice).
If you see a sick, injured or dead marine mammal in California, Oregon or Washington, call: NOAA Fisheries West Coast Region Stranding Hotline at (866) 767-6114. Do not touch or move sick wild animals, and keep pets away to help protect people, pets and wildlife (source).
Implications for Paso Robles, California
Economic impact: Paso Robles relies on tourism, including wine tourism and events. Although Año Nuevo is coastal, park closures and attention about avian flu in elephant seals could reduce regional visitation temporarily. Businesses that serve travelers — hotels, restaurants and tasting rooms — may see fewer day visitors; wineries should brief staff on safe wildlife contact protocols.
Political and fiscal consequences: Local leaders may press for transparency, timelines and precise accounting of surveillance and response expenditures to ensure efficient use of taxpayer dollars and minimize economic disruption (Parks news release).
Social and community effects: Residents who travel to the coast or keep pets may worry. Remind households to keep pets leashed and away from carcasses or sick animals; veterinary clinics should coordinate with county public health for guidance (guidance).
Practical applications for residents and businesses:
- Travel planning: Avoid detours to closed viewing areas; follow state park advisories (news release).
- Pet care: Keep pets away from beaches with marine wildlife; report suspicious animals to authorities (A Flu Diary).
- Local agencies: Coordinate with state and federal partners to issue timely local alerts and protect tourism without compromising safety (report).
- Business preparedness: Wineries and venues should plan flexible cancellation or rescheduling policies and reassure guests that risk is low when precautions are followed.
Sources and further reading
- Mongabay: Avian flu strikes California’s northern elephant seals; area quarantined
- California Department of Parks and Recreation news release
- UC Davis Veterinary Medicine: First cases of avian influenza detected in California’s northern elephant seals
- CIDRAP: California records avian flu in northern elephant seals
- The Marine Mammal Center announcement
- DVM360 coverage
- RSOE EDIS incident details
- A Flu Diary: California DPH advice to public after elephant seals test positive
- Stocktonia reporting on bird flu and California elephant seals
- Smithsonian Magazine coverage
Health & safety reminder: Do not touch or move sick wild animals; keep pets away. Report sick, injured or dead marine mammals to the NOAA Fisheries West Coast Region Stranding Hotline at (866) 767-6114.
