What started with pelicans is now killing sea lions
Along Peru's coastal shores, a silent catastrophe has been unfolding since November 2022, as the H5N1 avian influenza virus — long a threat to bird populations — has crossed into the realm of marine mammals, killing over 63,000 birds and 716 sea lions across seven protected natural areas. What began as a regional outbreak has spread across an entire continent, touching Ecuador, Bolivia, Chile, Paraguay, Argentina, and Uruguay, reminding us that in nature, boundaries between species and nations are far more permeable than we imagine. Peru's crews, dressed in protective suits, continue their grim work of collecting and burying the dead, bearing witness to a viral force that does not distinguish between the air and the sea.
- H5N1, already responsible for over 200 million bird deaths worldwide since 2021, has made an alarming leap — sea lions along Peru's central coast are now dying in the hundreds, a species crossing that scientists describe as deeply unusual.
- The speed of the die-off is as unsettling as its scale: sea lions that appeared healthy weeks ago are now washing up dead on beaches that fall within Peru's most protected natural reserves.
- With a sea lion population of roughly 110,000 animals concentrated near Ica and the Paracas reserve, Peru faces the prospect of losing a significant portion of a species it has long sheltered — and there is no vaccine, no treatment, only removal of the dead.
- The virus has fanned out across South America, detected in six additional countries, with Chile also reporting sea lion deaths, raising fears that the marine mammal die-off is not Peru's burden alone.
- Crews in hazmat gear continue working the beaches daily, burying carcasses in the sand while wildlife officials watch the numbers rise and wait for signs that the outbreak may be nearing its peak.
Since mid-January, workers in protective suits have been walking Peru's central coast beaches, collecting the bodies of sea lions and digging graves for them in the sand. The toll so far: 716 sea lions dead across seven protected natural areas, with the count still rising.
The outbreak began with birds. Peru recorded its first H5N1 case in November 2022 in the country's north, and the virus moved with startling speed. By February, it had killed 63,000 birds — the great majority of them pelicans that nest and feed along the Peruvian coast. Then, in January, the sea lions began dying too. Roberto Gutierrez of Peru's National Service of Natural Protected Areas called the sea lion deaths unusual. Veterinarian Javier Jara was more direct: what had been a bird problem had become a marine mammal problem. The virus had crossed from one species to another.
Peru's sea lion population stood at around 110,000 animals in 2020, concentrated near the Ica region and the Paracas nature reserve. In a matter of weeks, more than 700 were dead. There is no vaccine for sea lions, no treatment available — only the ongoing labor of removing bodies and hoping the outbreak peaks before the losses grow worse.
The crisis extends well beyond Peru's borders. H5N1 has now been detected across South America — in Ecuador, Bolivia, Chile, Paraguay, Argentina, and Uruguay — and Chile has also reported sea lion deaths. Globally, the virus has killed or forced the culling of more than 200 million birds since 2021. Brazil, the world's largest poultry exporter, has so far been spared, but the virus continues its continental march. What makes Peru's situation distinct is not just the numbers, but the speed: animals that were alive and healthy weeks ago are now washing up dead on shores that were, not long ago, among the most protected in the country.
Peru is burying its dead by the hundreds. Not people—sea lions. Since mid-January, crews in protective suits have been collecting carcasses from beaches along the central coast, digging graves in the sand for animals that died of bird flu. So far, 716 sea lions have washed up dead across seven protected natural areas. The count keeps climbing.
It started with birds. In November, Peru recorded its first case of H5N1 in the northern part of the country. The virus moved fast. By February, it had killed 63,000 birds, the vast majority of them pelicans that nest and feed in Peru's coastal waters. The pelicans died first, their bodies accumulating on shores and in protected reserves. Then, in January, something unexpected happened: the sea lions began to die too.
Roberto Gutierrez, who oversees surveillance for Peru's National Service of Natural Protected Areas, described the sea lion deaths as unusual. The timing was strange. The scale was strange. A veterinarian named Javier Jara, working with Peru's National Forestry and Wildlife Service, put it plainly: what had started as a bird problem last year was now killing marine mammals. The virus had crossed from one species to another, from air to sea.
Peru's sea lion population numbered around 110,000 animals in 2020, concentrated mainly along the coast in the Ica region and around the Paracas nature reserve. That's the baseline. That's what was there before. Now, in a matter of weeks, more than 700 of them were dead, and the crews in their plastic suits and masks were still collecting bodies.
The outbreak is not contained to Peru. Since the start of 2021, H5N1 has killed more than 200 million birds worldwide, according to the World Organization for Animal Health—some from the disease itself, others culled in attempts to stop its spread. In South America alone, the virus has been detected in Ecuador, Bolivia, Chile, Paraguay, Argentina, and Uruguay. Chile, like Peru, has now recorded H5N1 in a sea lion. Brazil, the world's largest poultry exporter, remains unaffected so far, but the virus is moving through the continent.
What makes Peru's situation distinct is the scale of the marine mammal die-off and the speed with which it happened. The sea lions were not sick for months before dying. They appeared suddenly, in large numbers, dead on beaches that had been safe weeks before. The crews kept working, kept burying them. The virus kept spreading. There is no vaccine for sea lions. There is no treatment. There is only the work of removing the bodies and hoping the outbreak peaks soon.
Citas Notables
We have recorded since mid-January the unusual death of many sea lions, so far we have about 716 dead sea lions in seven protected natural areas of the coast.— Roberto Gutierrez, head of surveillance, National Service of Natural Protected Areas
What we remember initially started with pelicans last year is now affecting these marine mammals.— Javier Jara, veterinarian, Peru's National Forestry and Wildlife Service
La Conversación del Hearth Otra perspectiva de la historia
Why did the sea lions die so suddenly? Was there a trigger?
The virus was already in the water, in the birds they eat. Once H5N1 got into the pelican population, it was only a matter of time before the sea lions caught it through their food chain. The birds died first; the sea lions followed.
Is 716 sea lions a catastrophic number for Peru's population?
It depends on the total. Peru had about 110,000 sea lions in 2020. So we're talking less than one percent so far. But the die-off is still happening. We don't know where it stops.
Why is this spreading so fast across South America?
H5N1 doesn't respect borders. It moves with migrating birds, with ocean currents, with the animals that eat infected prey. Once it's in one country, it's in the region.
What happens if it reaches Brazil?
Brazil is the world's largest poultry exporter. If H5N1 gets into their commercial flocks, it's not just a wildlife story anymore. It becomes an economic crisis.
Are the crews burying the sea lions trying to prevent further spread?
Partly. But there's also no other option. You can't leave hundreds of dead animals on public beaches. The burial is containment and cleanup at once.
What's the worst-case scenario here?
The virus keeps jumping to new species. The sea lion population crashes. It spreads to commercial farms. And we're still in the early stages of understanding how H5N1 behaves in marine mammals.