By: Julia Valencia

Opinion Editor 

An outbreak of the bird flu in Northern California has killed at least 30 elephant seal pups as of late February, with numbers continuing to climb. The disease broke out at Año Nuevo State Park in San Mateo County, where at least seven pups have tested positive for the virus, formally known as H5N1.

Though people can see them at the state park year-round, from mid-December to early March, thousands of elephant seals congregate on the beach, where they breed and give birth to pups. By mid-March, most adult elephant seals have departed, but the young seals will stay through April. The disease affects the seals’ brain function, manifesting as body tremors, seizures, and weakness, leading to rapid health decline and eventually death. In late 2023, H5N1 made its way into Argentina’s elephant seal population, killing over 17,000 pups and more than 50,000 adult females on an island off South Georgia. The seals killed in the Southern Hemisphere are very similar to those infected in California, leading to a large cause for concern. 

Roxanne Beltran, an ecologist at the University of California, Santa Cruz, is spearheading a long-term monitoring project on the seals. She shared that there are some hopeful signs in the colony, one of them being that “we haven’t seen an exponential uptick in mortalities,” and that the majority of the seals seem healthy. She also explained that when researchers first discovered the virus, most female adult seals had left the beach for the season, so only about 1,350 seals remained. Beltran said, “I think we’re really nervous about the trajectory of this outbreak, which, of course, we can’t predict.” This is the first report of the disease in northern seals, which breed along the Pacific coasts of the United States and Mexico. In the 19th century, elephant seals were nearly hunted to extinction, and the flu outbreak could pose a significant threat to the seals’ population once again. 

Over the past few years, a more aggressive form of H5N1 has affected a larger group of animals, including foxes, cows, cats, bears, and an unusually large array of birds. In the U.S. the virus has affected over 1,000 herds of cattle ranging across 19 states. Since 2024, there have been 70 reported cases of the bird flu in people, with most coming from dairy farm workers. 

Though the current risk to the public is low, Año Nuevo State Park closed certain beaches and suspended guided tours for the rest of the season. Officials are warning Californians to stay away from the seals, regardless of how they appear. They are also recommending that dog owners keep dogs away from beaches, or at the very least, use a leash. Researchers remain hopeful that they will find a way to counteract the virus in the elephant seals and keep their populations strong. 

(Sources: California State Parks, NY Times, SF Chronicle)