Bird Flu Outbreak Closes Elephant Seal Tours at Año Nuevo State Park
A highly pathogenic avian influenza (HPAI) H5N1 outbreak has been confirmed in northern elephant seal pups at Año Nuevo State Park in California, prompting the closure of the park’s popular seal-watching area and the cancellation of tours. The outbreak marks the first confirmed detection of the virus in a marine mammal population in the state, according to wildlife experts.
The initial detection came after researchers observed flu-like symptoms in seven weaned pups between and , coinciding with an increase in sick and dead seals within the park. Laboratory tests subsequently confirmed the presence of the H5N1 virus in those seven pups, with results pending on samples from another 30 animals, as of .
“This is exceptionally rapid detection of an outbreak in free-ranging marine mammals,” said Christine Johnson, director of the Institute for Pandemic Insights at the University of California, Davis Weill School of Veterinary Medicine. “We have most likely identified the very first cases here because of coordinated teams that have been on high alert with active surveillance for this disease for some time.”
The outbreak occurs against a backdrop of a global spread of HPAI H5N1, which began in 2020. The virus has resulted in the deaths of millions of domesticated birds and has been detected in wildlife across every continent, including numerous species of wild birds and several mammals. Recent outbreaks have impacted marine mammal populations elsewhere, including thousands of sea lions in Chile and Peru, thousands of elephant seals in Argentina, and hundreds of seals in New England.
While the virus is currently considered a low risk to humans, officials are advising the public to avoid approaching seals and to keep pets away from the animals. The closure of the Año Nuevo State Park viewing area and the cancellation of tours – including 22 school tours – are precautionary measures intended to limit potential spread and protect both the seals and visitors. Full refunds are being offered for cancelled reservations through Reserve California.
“Out of an abundance of caution, access is being paused to give wildlife space and allow for ongoing monitoring,” stated Jordan Burgess, Deputy District Superintendent for California State Parks. “We definitely are not panicking about human exposure at this time, but rather ensuring the health of the seals and the public.”
Año Nuevo State Park, located approximately 90 minutes south of San Francisco, is a critical breeding ground for northern elephant seals. Thousands of the animals gather there each winter to mate and give birth, attracting both tourists and wildlife enthusiasts. The park is home to one of the largest mainland breeding colonies of northern elephant seals in the world.
Researchers from the University of California, Santa Cruz, and UC Davis are collaborating with state and federal wildlife agencies, as well as The West Coast Marine Mammal Stranding Network, to monitor the situation and track the progression of the virus within the seal colony. Officials expressed cautious optimism that the majority of adult female seals had already begun their routine migrations before the outbreak began, potentially limiting the scope of the impact.
The rapid detection of the outbreak is attributed to proactive surveillance efforts. Veterinarians, public health officials, and wildlife agencies have been tracking HPAI H5N1 since its emergence in 1996, recognizing its potential to jump species and cause widespread illness. The current situation highlights the ongoing threat posed by the virus and the importance of continued monitoring of wildlife populations.
The confirmed cases at Año Nuevo State Park represent a significant development in the ongoing global avian influenza crisis, raising concerns about the potential for further spread among marine mammal populations and the need for continued vigilance and coordinated response efforts.